PREGLED NAUČNIH I STRUČNIH REZULTATA INSTITUTA IMS U 2012. GODINI
Institut za ispitivanje materijala a.d.
Beograd, decembar 2012. PREGLED NAUČNIH I STRUČNIH REZULTATA INSTITUTA IMS U 2010. GODINI
Izdavač Institut IMS a.d. Beograd, Bulevar vojvode Mišića 43 [email protected] www.institutims.rs
Za izdavača Dr Vencislav Grabulov
Urednici Dr Vencislav Grabulov Dr Aleksandra Mitrović Goran Petrović
Obrada podataka Ljiljana Dmitrović
Štampa Razvojno-istraživački centar grafičkog inženjerstva Tehnološko-metalurški fakultet, Beograd, Karnegijeva 4
Tiraž 250 primeraka Na kraju ove, 2012. godine, Institut IMS predstavlja rezultate rada u nauci, kao i stručnog angažovanja na značajnijim projektima. Rezultati naučno- istraživačkog rada su razvrstani prema klasifikaciji resornog ministarstva.
Tokom godine, Institut za ispitivanje materijala je ostvario ozbiljne naučne i poslovne uspehe. U okviru tekućeg ciklusa naučnih projekata za period 2011- 2014. godina, 22 istraživača Instituta IMS uključeni su u realizaciju sedam projekata iz tehnološkog razvoja, jedan integralni projekat i četiri projekta iz programa osnovnih istraživanja. Ono čime se Institut IMS može ponositi je 14 mladih istraživača upisanih na doktorske studije, čije školovanje finansiramo iz sopstvenih sredstava. Rezultati istraživačkog rada su u skladu sa dosadašnjim trendom rasta broja publikacija u međunarodnim časopisima i učešća istraživača na vodećim međunarodnim skupovima. Institut IMS je organizator tri naučno-stručna skupa, od kojih dva međunarodnog značaja.
Odabrane stručne reference su, kao i svake godine, impresivne. Uz sve probleme sa kojima je suočena domaća privreda, a posebno građevinska industrija, Institut IMS je uspeo da obezbedi učešće u najznačajnijim projektima u zemlji i regionu. U skladu sa višedecenijskom tradicijom i ugledom, kao i širokim spektrom usluga koje pružamo, bili smo angažovani na projektovanju, ispitivanjima i istraživanjima građevinskih objekata, materijala i proizvoda, primeni tehnologija građenja i sistema prednaprezanja.
Među važnijim objektima na kojima smo bili angažovani u 2012. godini pominjemo mostove Zemun-Borča, Gazela, novi Žeželjev most u Novom Sadu, most preko Ade, zaštićeno graditeljsko nasleđe kao što je Pećka patrijaršija ili Viminacijum, putne objekte na obilaznici oko Beograda i duž autoputeva i magistralnih i regionalnih puteva u Srbiji, u Rafineriji nafte Pančevo, MK Mountain Resort na Kopaoniku, hidro i termo-elektrane u regionu, posebno revitalizacija HE Đerdap 1, mini hidro-elektrane, naselja Stepa Stepanović i dr Ivan Ribar, vetroparkove, kompleks IKEA, gasovod „Južni tok“, silos cementare u Kaknju, realizovan pilot-objekat u okviru revitalizacije IMS tehnologije građenja u Osijeku.
Urednici
Pregled naučnih i stručnih rezultata u 2012. godini 1 SADRŽAJ
REZULTATI NAUČNO-ISTRAŽIVAČKOG RADA ...... 5 1. Monografija (M12) ...... 5 1. RADOVI U TEMATSKIM ZBORNICIMA MEĐUNARODNOG ZNAČAJA (M14)...... 8 2. RADOVI OBJAVLJENI U NAUČNIM ČASOPISIMA MEĐUNARODNOG ZNAČAJA (M20) ...... 9 Rad u vodećem međunarodnom časopisu M21 ...... 9 Rad u istaknutom međunarodnom časopisu M22 ...... 11 Rad u međunarodnom časopisu M23 ...... 13 3. ZBORNICI MEĐUNARODNIH NAUČNIH SKUPOVA (M30) ...... 24 Saopštenje sa međunarodnog skupa štampano u celini (M33) ...... 24 Saopštenje sa međunarodnog skupa (M34) ...... 57 4. ČASOPISI NACIONALNOG ZNAČAJA (M50) ...... 65 Rad u časopisu nacionalnog značaja (M51) ...... 65 Rad u časopisu nacionalnog značaja (M52) ...... 70 Rad u naučnom časopisu (M53) ...... 72 5. ZBORNICI SKUPOVA NACIONALNOG ZNAČAJA (M60) ...... 75 Predavanje po pozivu na skupu nacionalnog značaja štampano u celini (M61) ...... 75 Saopštenje sa skupa nacionalnog značaja štampano u celini (M63) ...... 76 Saopštenje sa skupa nacionalnog značaja (M65) ...... 89 6. DOKTORSKE DISERTACIJE I MAGISTARSKI RADOVI (M70) ...... 91 Odbranjena doktorska disertacija (M71) ...... 91 7. PATENTI, AUTORSKE IZLOŽBE (M90) ...... 93 2 Institut za ispitivanje materijala a.d. Beograd
Realizovani patent, arhitektonsko, građevinsko ili urbanističko autorsko delo (M92) ...... 93 8. ORGANIZACIJA NAUČNO-STRUČNIH SKUPOVA ...... 94 Međunarodni naučno-stručni skupovi ...... 94 Domaći naučno-stručni skup sa međunarodnim učešćem ...... 96 9. NAGRADE I PRIZNANJA ...... 97 10. NAUČNI PROJEKTI FINANSIRANI OD STRANE MINISTARSTVA PROSVETE I NAUKE ...... 99 ODABRANE STRUČNE REFERENCE ...... 104 CENTAR ZA MATERIJALE ...... 104 CENTAR ZA METALE I ENERGETIKU ...... 110 CENTAR ZA PUTEVE I GEOTEHNIKU ...... 115 CENTAR ZA KONSTRUKCIJE I PREDNAPREZANJE ...... 119 SERTIFIKACIONO TELO ...... 128 Pregled naučnih i stručnih rezultata u 2012. godini 3
REZULTATI NAUČNO- ISTRAŽIVAČKOG RADA
4 Institut za ispitivanje materijala a.d. Beograd Pregled naučnih i stručnih rezultata u 2012. godini 5
REZULTATI NAUČNO- ISTRAŽIVAČKOG RADA 1. MONOGRAFIJA (M12)
A. Terzić, Lj. Pavlović, V. Mitić
DETERMINATION OF APARENT POROSITY LEVEL OF REFRACTORY CONCRETE USING ULTRASONIC PULSE VELOCITY TECHNIQUE AND IMAGE ANALYSIS Mechanical Properties and Performance of Engineering Ceramics and Composites VI: Ceramic Engineering and Science, Vol. 32, John Wiley & Sons, Inc., Hoboken, NJ, USA, 2011, 151–161. Aim of this paper is to establish the correlation between sintering process, porosity and important thermo-mechanical property of refractory concrete, i.e. creep. Creep deformation was investigated according to standard laboratory procedure alied at three temperatures: 1200, 1300 and 1400ºC. Corundum and bauxite based refractory concretes were investigated. The concretes are varying in chemical and mineralogical composition. Both loss of strength and degradation of material occur when refractory concrete is subjected to increased temperature and compressive static load. Measuring of thermo-mechanical properties can indicate and monitor the changes within microstructure. Variation of refractory concrete microstructure, as a consequence of sintering process, during exposure to constant compressive load and constant elevated temperature during certain time-intervals was investigated using scanning electron microscope and Image Pro Plus program for image analysis. Obtained results of the investigation proved that creep can be useful method when type of refractory concrete is to be chosen for an alication. Keywords: creep, concrete, image analysis, pore size distribution, microstructure 6 Institut za ispitivanje materijala a.d. Beograd
I. Atanasovska, R. Mitrović, D. Momčilović
EXPLICIT PARAMETRIC METHOD FOR OPTIMAL SPUR GEAR TOOTH PROFILE DEFINITION Advanced Materials Research Vol. 633, Trans Tech Publications, Switzerland. DOI:10.4028, 87–102 The gear tooth profile has an immense effect on the main operating parameters of gear pairs (load capacity, working life, efficiency, vibrations, etc). In current engineering research and practice, there is a strong need to develop methods for tooth profile optimization. In this paper a new method for selecting the optimal tooth profile parameters of spur gears is described. This method has been named the Explicit Parametric Method (EPM). The addendum modification coefficient, radius of root curvature, and pressure angle of the basic rack for cylindrical gears, have been identified as the main tooth profile parameters of spur gears. Therefore, the EPM selects the optimal values for these three tooth profile parameters. Special attention has been paid to develop a method of adjustment for the particular working conditions and explicit optimization requirements. The EPM for optimal tooth profile parameters of gears uses contact nonlinear Finite Element Analysis (FEA) for calculation of deformations and stresses of gear pairs, in addition to explicit comparative diagrams for optimal tooth profile parameter selection. Keywords: spur gears, optimization, Explicit Parametric Method (EPM), finite element analysis
Z. Kovačević,Z. Karastojković, V. Aleksić
ON-SITE METALLOGRAFY & REPLICA METHOD FOR INSPECTION CONNECTING ROD MATERIAL AND CRACKS DETECTION Toyotarity Production Factors, Chapter 3, Dnipropetrovsk, 2011, 41–56. Testing of materials properties is usually a discipline for the quality assurance during manufacturing processes. In condition monitoring, certification or upgrading of existing plants and in failure analysis similar benefits from non destructive testing of materials properties can be achieved. Another benefit from the Non Destructive Metallography (NDM) is that the test can be made on-site. Pregled naučnih i stručnih rezultata u 2012. godini 7
NDM is a well established and proven tool to help determine the integrity of generator and hydro turbine components during their life-cycle in power plant environments. On-site metallography of components makes it possible to evaluate a material's microstructure. It allows microstructural analysis of large components that are difficult to move or not permitted to be destructively tested, enabling rapid evaluation of the material. Here are monitored the microstructural changes and crack detection in St 35 connecting rod steel after aroximately 15 years in service. The paper includes a short description the replica method as a technique for microstructural examination of components by using nondestructive testing method. 8 Institut za ispitivanje materijala a.d. Beograd
1. RADOVI U TEMATSKIM ZBORNICIMA MEĐUNARODNOG ZNAČAJA (M14)
M. Vasić, Z. Radojević, Ž. Grbavčić
METHODS OF DETERMINATION FOR EFFECTIVE DIFFUSION COEFFICIENT DURING CONVECTIVE DRYING OF CLAY PRODUCTS Clay minerals in nature – their characterization, modification and alication, InTech, Hrvatska, 295–312. The purpose of this chapter is to calculate the effective diffusion coefficient based on experimentally recorded drying curves for several masonry clays obtained from different masonry clay units manufacturers. Calculation methods and computer programs, specially designed for this purpose are developed. First calculation method is based on the mathematical calculation of the second Fick's law and Cranck diffusion equation. Second one is based on the analytical solution of the Efremov differential diffusion equation with a boundary condition in the form of the flux. In both calculation methods, two program variations are designed to compute the effective diffusion coefficient. Four models (A1, A2, B1 and B2) for predicting the drying behaviour are obtained as the result of cited program calculation. The results presented in this paper show that the values of the effective diffusion coefficient determined by the designed computer programs have similar values to those available in the literature for the same coefficient for different clays. Based on the mathematically determined prognostic value of the effective diffusion coefficient, it was concluded that, whatever the initial mineralogical composition of the clay, there is 90% agreement of the calculated prognostic drying curves with the experimentally recorded ones. When a shrinkage correction of the masonry products is introduced into the calculation step, this agreement is even better. Pregled naučnih i stručnih rezultata u 2012. godini 9
2. RADOVI OBJAVLJENI U NAUČNIM ČASOPISIMA MEĐUNARODNOG ZNAČAJA (M20)
RAD U VODEĆEM MEĐUNARODNOM ČASOPISU M21
K. Janković, D. Nikolić, D. Bojović
CONCRETE PAVING BLOCKS AND FLAGS MADE WITH CRUSHED BRICK AS AGGREGATE Construction and Building Materials, 2012, No. 28, 559–663. Demolition of old buildings in urban cores has produced a large amount of waste material. Since they are mostly masonry structures the largest part of the waste material is ceramic waste. Besides that, ceramic waste is obtained as a byproduct in the ceramic industry. All of this initiated a research for the alication of concrete with recycled brick as aggregate. In this paper, the possibility of using crushed bricks in the production of concrete elements for the pedestrian zone is shown. The alication of recycled brick as aggregate, produces concrete of less density and strength, and of increased absorption. All of this also has an effect on the quality of concrete flags and paving blocks. Based on the results obtained by testing the resistance to frost of concrete it was assumed that it is possible to get the products comply with European standards. The results show that replacing up to a 32.5% of natural aggregate with crushed brick aggregate produces concrete blocks, and up to 65% of it produces concrete paving flags which meet the requirements of European standards.
M. Arsenović, Z. Radojević, S. Stanković
REMOVAL OF TOXIC METALS FROM INDUSTRIAL SLUDGE BY FIXING IN BRICK STRUCTURE Construction and Building materials, Vol. 37 (2012), 7–14. http://dx.DOI.org/10.1016/j.conbuildmat.2012.07.002 10 Institut za ispitivanje materijala a.d. Beograd
The aim of this study was to test utilization possibilities of industrial sludge in masonry industry, as well as risk of toxic elements leaching potential. Sludge is generated in a hot-dip galvanizing process after waste water neutralization. This waste is considered to be hazardous due to the presence of toxic elements, which can be fixed within heavy clay matrix after thermal treatment. Relatively large amounts of toxic metals were found in used raw materials, but their leachability reduces to a negligible level after firing at 1020 _C. The results show that sludge can be used to produce eco-friendly bricks Pregled naučnih i stručnih rezultata u 2012. godini 11
RAD U ISTAKNUTOM MEĐUNARODNOM ČASOPISU M22
A. Prstić, Z. Aćimović-Pavlović, A. Terzić, Lj. Pavlović, S. Grujić
DEVELOPMENT OF NEW CORDIERITE-BASED REFRACTORY COATINGS FOR CASTING ALICATIONS International Journal of Alied Ceramic Technology (2012), 1–11. In this study, new refractory coatings based on synthesized cordierite for the casting alications were developed. The investigation included starting raw materials characterization, synthesis of the cordierite, design of the refractory coating as final product and its alication testing. The obtained results pointed out that coating suspension sediment stability was crucial quality parameter. Design and optimization of the coatings composition, with controlled rheological properties included, were achieved by alication of different coating components, namely different suspension agents and by alteration of the coating production procedure. Cordierite, used as filler, was obtained by means of synthesis in the solid state reaction on the basis of talc, kaolin and alumina. The investigation showed that the alication of these particular types of water/alcohol based coatings has positive influence on surface quality, structural and mechanical properties of the castings of aluminum alloys obtained by casting into sand molds by means of evaporable models method; i.e. evaporate pattern casting process. Keywords: refractory coating, cordierite, synthesis, sand casting, evaporate pattern casting process.
D. Momčilovic, Z. Odanović, R. Mitrović, I. Atanasovska, T. Vuherer
FAILURE ANALYSIS OF HYDRAULIC TURBINE SHAFT Engineering Failure Analysis, 2012, Vol. 20, March 2012, 54–66. This paper describes the analysis of major failure of 28 MW horizontal hydro turbine shaft. The analysis of load carrying capacity of critical radius and fractography analysis are presented. Special emphasize is on metallurgical failure analysis of in-service crack initiation. The analysis of stresses is obtained 12 Institut za ispitivanje materijala a.d. Beograd by the finite element method and the developed model and load conditions are described. Finite element analysis is performed for case of normal service and start-up regime. Based on the failure analysis and numerical calculations, it could be concluded that the seal box design led to constant flow of river water in zone of critical radius which resulted as occurrence of corrosion fatigue cracks and major failure of turbine shaft. Suggestions for problem solution for the turbine shaft are also presented. Keywords: Failure analysis, Shafts, Cracks, Corrosion fatigue
Pregled naučnih i stručnih rezultata u 2012. godini 13
RAD U MEĐUNARODNOM ČASOPISU M23
M. Ćosić, Z. Aćimović-Pavlović, A. Terzić, B. Nedeljković, Lj. Pavlović
PROCESS PARAMETERS INFLUENCE ON MICROSTRUCTURAL PROPERTIES OF HYPEREUTECTIC AL-18WT% SI ALLOYS OBTAINED BY RHEOCASTING PROCESS Metalurgia International, 2012, Vol. XVII, no. 3, 88–93. Hypereutectic Al-18wt%Si alloy was obtained by conventional and rheocasting -1. Samples of rheocasted alloy were obtained at two stirring speeds 1000 and 1500 rpm. Tests showed that two major changes of microstructural properties of rheocasting alloy, in comparison with conventional alloy, are change of dendrite morphology into nondendrite -Al and Si). Both changes of primary particles were monitored in area near the stirrer and at a small distance from the -Al particles decreased with stirring speed increment, while roundness of particles increased with stirring speed increment. Stirring speed change led to different degree of primary Si particles agglomeration. At stirring speed 1000 rpm, Si particles are uniformly distributed, while at speed 1500 rpm, a tendency to form clusters is more expressed. Test results were discussed on basis of utilizing fragmentation- agglomeration mechanism of primary phase evolution in a semi-solid melt, which may contribute to explanation of semi-solid structure development. Keywords: aluminum silicon alloy, primary silicon, microstructure, rheocasting, mechanical stirring.
A. Prstić, Z. Aćimović-Pavlović, M. Đurić, A. Terzić, Lj. Pavlović
SYNTHESIS, CHARACTERIZATION AND ALICATION OF THE FILLER BASED ON CORUNDUM FOR OBTAINING THE CERAMIC COATS IN FOUNDRY Metalurgia International, 2012, Vol. XVII, no. 3, 88–93. 14 Institut za ispitivanje materijala a.d. Beograd
In this work, a possibility to develop new ceramic coats based corundum for casting alications has been examined. Optimization of coating composition with controlled rheological properties was attained by alying different coating components, and by alteration of coating production procedure. As filler, corundum powder with particle size of 20x10-6 m and 40x10-6 m was used. The corundum sample was tested by the following methods: X-ray diffraction analysis and with polarized microscope. The shape and grain size were analyzed by the program package OZARIA 2.5. It was shown that alication of this type of water-alcohol-based coating had a positive influence on surface quality, structural and mechanical properties of the castings of Fe-C and Al alloys obtained by casting into sand molds, according to the method of expandable patterns (EPC process). Keywords: sand casting, expandable patterns casting process, refractory coating, corundum.
A. Terzić, Z. Radojević, Lj. Miličić, Lj. Pavlović, Z. Aćimović
LEACHING OF THE POTENTIALLY TOXIC POLLUTANTS FROM COMPOSITES BASED ON WASTE RAW MATERIAL Chemical Industry & Chemical Engineering Quarterly, 2012, Vol. 18: no 3, 373−383. The disposal of the fly ash generated in coal based power-plants may pose a significant risk to the environment due to the possible leaching of hazardous pollutants, such as toxic metals. Also, there is a risk of leaching even when fly ash is built-in the construction composites. Fly ashes from various landfills were alied in several composite samples (mortar, concrete and brick) without any physical or thermal pre-treatment. The leachability of the potentially toxic pollutants from the fly ash based products was investigated. The leaching behavior and potential environmental impact of the 11 potentially hazardous elements was tracked: Pb, Cd, Zn, Cu, Ni, Cr, Hg, As, Ba, Sb and Se. A detailed study of physico-chemical characteristics of the fly ash, with accent on trace elements and the chemical composition investigation is included. Physico/chemical properties of fly ash were investigated by means of X-ray fluorescence, differential thermal analysis and X-ray diffraction methods. Scanning electron microscope was used in microstructural analysis. The results show that most of the elements are more easily leachable from the fly ash in Pregled naučnih i stručnih rezultata u 2012. godini 15 comparison with the fly ash based composites. The leaching of investigated pollutants is within allowed range thus investigated fly ashes can be reused in construction materials production. Keywords: fly ash, construction materials, leaching test, toxic pollutants, possible reuse.
I. Belić, Z. Acimovic-Pavlovic, A. Terzić
THE POSSIBILITY OF SUBSTITUTION OF WEAR RESISTANT LOW CHROMIUM WHITE IRON RESISTANT WITH BASALT MELT Metalurgia International, 2012, Vol. XVII, no. 5, 104–107. In this study the testing results of the possibility of substituting mill lining plates for ore milling made of low chromium white iron that is resistant to wear with plates made of basalt melt are presented. Plates made of chromium white iron with 10% Cr and plates made of basalt from the ore of Kopaonik – Serbia are both produced by the sand mould casting method. The microstructure characteristics and properties of metal and basalt plates have been tested depending on the parameters of the melting and casting process, the cooling regime and the crystallization of castings. Testing of the alication of basalt plates in exploitation in industrial conditions has proved to have good results. Keywords: low chromium white iron, basalt melt, resistance to wear, image analysis, high temperature material, microstructure.
A. Prstić, Z. Aćimović-Pavlović, Lj. Andrić, J. Stojanović, A. Terzić
ZIRCON-BASED COATING FOR THE ALICATIONS IN LOST FOAM CASTING PROCESS Chemical Industry and Chemical Engineering Quarterly, 2012. In this work, a possibility to develop a new zircon-based refractory coating for casting alications was investigated. Optimization of the coating composition with controlled rheological properties was attained by alication of different coating components, particularly by alication of a new suspension agent and by alteration of coating production procedure. Zircon powder with particle size of 25x10-6 m was used as filler. The zircon sample was investigated by means of 16 Institut za ispitivanje materijala a.d. Beograd the following methods: X-ray diffraction analysis, diffraction thermal analysis and polarized microscope. The shape and grain size were analyzed by means of the PC program package OZARIA 2.5. It was shown that alication of this type of water-alcohol-based coating had a positive influence on surface quality, structural and mechanical properties of the castings of cast iron obtained by pouring into sand molds by means of the expandable patterns method (Lost Foam casting process). Keywords: sand casting, Lost Foam casting process, refractory coating, zircon.
A. Terzić, Lj. Pavlović, Z. Radojević, Lj. Miličić
EVALUATION OF CONCRETES WITH STANDARD AND RECYCLED RAW MATERIALS FOR HIGH TEMPERATURE ALICATION Revista Romana de Materiale / Romanian Journal of Materials, 2012, Vol. 42: no 2, 143–154. Concrete undergoing thermal treatment before and during life-service can be alied as building material for thermal insulation in high-temperature plants. When such concretes are designed with secondary raw materials they show satisfying performances. Sintering and microstructural changes occur within concrete with increasing temperature. Change progression can be monitored by measuring compressive strength and porosity with destructive and non- destructive tests (ultrasonic pulse velocity technique, image analysis). Experiment has been performed on standard, corundum concrete and recycled, bauxite concrete. Samples were thermally treated from 110 to 1500ºC. Destructive tests were used in compressive strength and porosity investigation. Non-destructive tests were performed in order to compare results. Creep testing was conducted to prove sintering process. Results showed that recycled concrete has equal properties as standard concrete. Keywords: ultrasonic pulse velocity, sintering, high-temperature concrete, image analysis, recycling. Pregled naučnih i stručnih rezultata u 2012. godini 17
S. Dević, M. Logar, M. Cocić
MINERALOGICAL CHARACTER OF LOESS FRAGMENTS FROM CLAY USED IN BRICK INDUSTRY Interceram - International Ceramic Review, 2012, 60, 184–185. Serbia is a rich clay deposits that are used as raw material for the brick industry. Deposits of brick clay are created in different environments [1-2]. Thus, we distinguish between alluvial-marsh, alluvial silty-loess, alluvial-lake, the coastal marine, alluvial loess deposits and other. Loess fragments often occur in the clays used in brick manufacture. Adequate preparation of such clay to increase its range of brick products. The paper describes the mineralogical character loess fragments based on the results obtained by examining the loess of the two clay alluvial loess deposits in Vojvodina. Some of the clay deposits formed in the alluvial loess environment (Čelarevo, Zrenjanin, Kovin, Golubinci, Ub).
R. Mitrović, D. Momčilović , O. Erić, I. Atanasovska, N. Hut
STUDY ON IMPACT PROPERTIES OF CREEP-RESISTANT STEEL THERMALLY SIMULATED HEAT AFFECTED ZONE Thermal Science, 2012, Vol. 16, No. 2, 513–525. The steam pipe line (SPL) and steam line material, along with its welded joints, subject to damage that accumulates during operation in coal power plants. As a result of thermal fatigue, dilatation of SPL at an operating temperature may lead to cracks initiation at the critical zones within heat affected zone (HAZ) of steam pipe line welded joints. By registration of thermal cycle during welding and subsequent HAZ simulation is possible to obtain target microstructure. For the simulation is chosen heat resisting steel, 12H1MF (designation 13CrMo44 according to DIN standard). From the viewpoint of mechanical properties, special attention is on impact toughness mostly because very small number of available references. After simulation of single run and multi run welding test on instrumented Charpy pendulum. Metallographic and fractographic analysis is also performed, on simulated 12H1MF steel from service and new, unused steel. The results and correlation between microstructure and impact toughness is discussed, too. 18 Institut za ispitivanje materijala a.d. Beograd
Keywords: heat resisting steel, heat affected zone, instrumented Charpy test, impact toughness
D. Jevtić,M. Knežević, D. Bojović
ALICATION OF NEURAL NETWORKS IN DETERMINATION OF COMPRESSIVE STRENGTH OF CONCRETE Romanian Journal of Materials, 2012,Vol. 42, No.1, 16–22. This paper presents the optimization of concrete mixtures composition related to a physical property and the process of production of trial mix design by using the multi-layered feed-forward neural networks. This optimization was conducted because there is no clear method of designing concrete mixture composition and for the purpose of shortening procedure of the trial mix design of concrete. Mix design depend on many variables and deterministic models cannot give good results. The goal of the research was to make a model of a neural network, on the set of available data from 288 trial mix, which would, with highest accuracy, predict the compressive strength of concrete at the age of 28 days. In order to attain as high accuracy of obtained results as possible, three levels of input data to the neural networks were considered. On each of the alied groups of input data, the neural networks with 1 and 2 hidden layers were formed. On the basis of the adopted neural network, an algorithm for usage of the network in actual situations was made, alied on an actual model.
Z. Odanović, M. Đurđević, P. Krstić, M. Arsić, B. Katavić
SOME ALICATIONS OF THE IMAGE ANALYSIS IN THE METAL MATERIAL SCIENCE Acta Physica Polonica A, Selected peer reviewed papers from the International Congress on Advances in Alied Physics and Materials Science - APMAS 2011, Antalys 2011, Vol. 121, No. 1, 2012, 111–113. In different areas of science such as medicine, biology and engineering the Image analysis (IA) is widely used. Quantitative measuring by the IA has also found alication in metal materials science, especially in metallographic microstructure analysis. The measuring of the linear and area dimensions of the microconstituents in the metal material structure performed by the image Pregled naučnih i stručnih rezultata u 2012. godini 19 analysis is presented in the paper. The effects of the heat treatment temperature on the brittle phase content in the structure of the heat resistant Ni-Cr-Co-W alloy were analysed. Investigation of the influence of the alloying elements content in the Al alloys for automotive alication, on dendrite arm spacing in the cast structure are also presented. Obtained results of the quantitative measured dimensions have shown direct impact of the process parameters on the analysed metals microstructure characteristics. All tests were performed by the light optical microscope with automatic image analyser. Presented experimental results are based of a large number of measurements. A statistical analysis was performed and a high correlation of the results was obtained. For the each of the presented investigations and analyzed phenomenon, a statistical mathematical model is suggested with the boundary conditions defined by the investigated intervals of variables. Keywords: image analysis, quantitative measurement, microstructure.
A. Terzić, Lj. Pavlović, N. Obradović, V. Pavlović, J. Stojanović, Lj. Miličić, Z. Radojević, M. Ristić
SYNTHESIS AND SINTERING OF HIGH-TEMPERATURE COMPOSITES BASED ON MECHANICALLY ACTIVATED FLY ASH Science of Sintering, 2012, Vol. 44, no. 2 135–146. Amount of fly ash which is and yet to be generated in the coming years highlights the necessity of developing new methods of the recycling where this waste can be reused in significant quantity. A new possibility for fly ash utilization is in high-temperature alication (thermal insulators or/and refractory material products). As such, fly ash has to adequately answer the mechanical and thermal stability criteria. One of the ways of achieving it is by alying mechanical activation procedure on fly ash. In present study, fly ashes from two different power plants were mechanically activated in a planetary ball mill. Mechanically treated fly ashes were cemented with two different binders: standard Portland cement and high-aluminates cement. Physico-chemical analysis and investigation of mineralogical components of composites are emphasized, due to the changes occurred in fly ash during mechanical activation and sintering of composites. Macro-performance of the composites was correlated to the microstructure of fly ash studied by means of XRD and SEM analysis. Thermal stability of crystalline phases was investigated with 20 Institut za ispitivanje materijala a.d. Beograd
DTA. Highlight was placed on determination of relationship between mechanically activated fly ash and obtained composites microstructure on one side and behavior of sintered composites on the other side. Keywords: Fly ash, Mechanical activation, Sintering, High-temperature performance, Recycling.
A. Mitrović, M. Zdujić
MECHANOCHEMICAL TREATMENT OF SERBIAN KAOLIN CLAY TO OBTAIN HIGH RECTIVE POZZOLANA J.Serb.Chem.Soc.,2012. Mechanochemical treatment of Serbian kaolin clay was carried out in a planetary ball mill using two different milling media, hardened steel or zirconia vials and balls. The samples obtained with various milling times were characterized by the particle size laser diffraction (PSLD), X-ray diffraction (XRD), differential scanning calorimetry/thermogravimetry (DTA/TGA) and Fourier-transform infrared (FTIR) analyses. Mechanochemical treatment induced amorphization of the kaolinite phase accompanied by dehydroxylation. It was found that for the given milling parameters, amorphization mainly took place in the milling period up to 15 min, and was completed after about 30 min of milling for both milling media used. The pozzolanic activities were determined by the Chapelle method. Milling in the hardened steel milling medium had no significant influence on pozzolanic activity, even though there was accumulated iron contamination. For both milling media, pozzolanic activity of 0.79 was obtained for the samples milled for 15 min and it remained almost unchanged with prolonged milling. The determined pozzolanic activity values are close to these of commercial metakaolinite or metakaolinite obtained by the heat treatment (calcination) of the same clay, therefore, indicating possibility for obtaining high reactive pozzolana by mechanochemical treatment. Keywords: Kaolin clay, Kaolinite, Metakaolinite, Mechanochemical treatment, Pozzolana. Pregled naučnih i stručnih rezultata u 2012. godini 21
M. Đurđević, Z.Odanović, Z. Hennadiy
DETECTION OF DENDRITE COHERENCY TEMPERATURE OF ALUMINUM ALLOYS USING SINGLE THERMOCOUPLE TECHNIQUE Praktische Metallographie-Practical Metallography, 2012, Vol. 49, No. 2, 86– 98. The Dendrite Coherency Point (DCP) temperature refers to the state of a solidifying alloy at which a coherent dendrite network is established during the formation of grains. There are three main aroaches for detection of DCP: (i) the thermal analysis method, (ii) mechanical (or rheological) technique and (iii) physical method based on the thermal diffusivity measurement technique. There are two basic variants of the thermal analysis method. In the late 1980’s Bäckerud developed a method that utilizes two thermocouples. The DCP is determined by identifying the point of minimum temperature difference at the – TC). Recently, has been revealed that utilization of the first derivative curve (dT/dt) plotted versus temperature also allows for analysis of the α-Al Dendrite Nucleation and Growth characteristics and consequently determination of the DCT. This paper will illustrate that the dendrite coherency temperature could be identified by the 1st derivative curve (the one- thermocouple method) with the same accuracy as well as by using two thermocouples technique. Keywords: dendrite coherency temperature (DCT), thermal analysis, aluminum alloys.
Z. Slović, Lj. Nedeljković, K. Raić, Z. Odanović
RELATIONSHIP BETWEEN THE COMMON OPTICAL BASICITY MODELS AND THE SULPHIDE CAPACITIES OF CAO-AL2O3-SIO2- MGO SLAG Kovove Mater, 2012, 50, 185–192. The correlations between the sulphide capacity and the optical basicity models available in literature are reviewed. The relationship between sulphide capacity and the optical basicity was investigated on plant data collected from the BOF plant in the temperature range of 1565–1650◦C. The goal of this work was to 22 Institut za ispitivanje materijala a.d. Beograd compare results given by alying common acceptable Young’s, Sosinsky- Sommerville’s, Tsao-Katayama’s and Taniguchi’s optical basicity as well as the KTH model for calculating the sulphide capacities. The present paper is focused on the thermodynamic aspect of sulphur refining CaO-Al2O3-SiO2-MgO ladle slag during LF ladle treatment. Thirty one heats were employed in the present study in real production conditions of low carbon steels. Keywords: steels, thermodynamics, analytical methods, optical basicity, sulphide capacity.
J. Đurđević, H. Sokolowski, Z. Odanović
DETERMINATION OF DENDRITE COHERENCY POINT CHARACTERISTICS USING FIRST DERIVATIVE CURVE VERSUS TEMPERATURE J. Therm Anal Calorim, 2012, Vol. 109, No. 2, 875–882. The dendrite coherency point (DCP) temperature refers to the state of a solidifying alloy at which a coherent dendrite network is established during the formation of grains. Several relatively complex methods for detection of the DCP temperature have been developed. There are four main DCP temperature testing aroaches: (i) the rheological technique, (ii) thermal analysis of the minimum temperature difference between two cooling curves, (iii) thermal analysis of the second derivative of one cooling curve, and (iv) the thermal diffusivity measurement technique. This paper follows up the proposed thermal analysis of one center cooling curve for the determination of the DCP characteristics such as: temperature, time, instantaneous solidification rate, and fraction solid. The first derivative of the cooling curve is plotted versus the temperature and time and the thermal characteristics of all metallurgical reactions, including the DCP are determined with the same accuracy achieved using the two thermocouple technique developed by Ba¨ckerud et al. [4, 5]. Statistical analysis of the DCP temperature using the one versus two thermocouple techniques shows R2 equal to 0.99. This research revealed that utilization of dT/dt versus the temperature curve methodology also allows for analysis of the a-Al dendrite nucleation and growth characteristics and consequent determination of the grain size. On-going work on this new methodology for characterization of other solidification events will be presented in subsequent papers. Pregled naučnih i stručnih rezultata u 2012. godini 23
Keywords: Aluminum alloys, Cooling curve, Dendrite coherency point.
M. Đurđević, G. Huber, Z. Odanović
SYNERGY BETWEEN THERMAL ANALYSIS AND SIMULATION J. Therm Anal Calorim, 2012. DOI 10.1007/s10973-012-2389-0 Available databases presently used by commercial simulation software packages for the aluminum casting industry are usually armed with material properties for only a few selected standard alloys. In the case of other alloys with different chemical compositions and refinement or modification treatment, thermal analysis could be an invaluable tool to gain necessary properties. The aim of this article is to demonstrate the potential alication of the cooling curve analysis in the existing simulation software by improving its accuracy. Keywords: Simulation, Thermal analysis, Aluminum alloys. 24 Institut za ispitivanje materijala a.d. Beograd
3. ZBORNICI MEĐUNARODNIH NAUČNIH SKUPOVA (M30)
SAOPŠTENJE SA MEĐUNARODNOG SKUPA ŠTAMPANO U CELINI (M33)
D. Berisavljević, N. Šušić, S. Ćorić
SETTLEMENTS OF SHALLOW FOUNDATIONS BASED ON FLAT DILATOMETER TEST RESULTS Scientific conference on planning, design, construction and building renewal INDIS 2012, Novi Sad, 2012. The Flat dilatometer is in commercial use since 1980. Experience gained worldwide indicates that dilatometer tests allow to gain more realistic deformation characteristics of the foundation soil. Paper presents example calculation of shallow foundation settlement based on deformation parameters obtained by flat dilatometer (DMT). Кeywords: dilatometer, constrained modulus, settlements.
M. Arsenović, Z. Radojević, A. Terzić, N. Mijatović, Lj. Miličić
SINTERING OF PRODUCTS BASED ON FLY ASH 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012, 1655–1662. The purpose of this study was to test utilization possibilities of fly ash as raw material for building products. Research was done on raw and fired samples made of landfill fly ash by dry pressing process. The samples were subjected to ceramic-technological tests, and analytical techniques are also used: SEM, XRD, DTA/TGA, XRF, AAS. Raw and fired material contains toxic metals, but the leachability of metals after firing reduces to a negligible level. Compressive strength increases significantly with firing temperature. Keywords: Fly ash, Building products, Toxic metals. Pregled naučnih i stručnih rezultata u 2012. godini 25
A. Terzić, Z. Radojević, Lj. Miličić, M. Arsenović, Lj. Pavlović
UTILIZATION POTENTIAL OF SERBIAN FLY ASH 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012, 1735–1742. Fly-ash has global utilization potential. Due to the fly-ash quantity generated and its hazardousness, a new aroach for this disclosed problem became necessity. Comparative characterization of physico-chemical and microstructural properties of the fly ash was performed. Grain-size distribution of the landfilled fly ash was correlated with other characteristics. Investigated fly ash showed thermal stability which is essence for high-temperature alication. Negligible level of organic impurities and toxic leachable elements and high pozzolanic reactivity improve ash utilization potential. Properties improvement by mechanical-activation was suggested. Keywords: Fly ash, microstructure, characteristics, utilization potential.
Lj. Pavlović, A. Terzić, Z. Aćimović-Pavlović
BUILDING CERAMICS BASED ON SLAG FROM METAL MAGNESIUM PRODUCTION 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012, 1141–1145. Alication possibilities of slag from metallurgical process of magnesium production in the plant „Bela Stena“ Baljevac, as an initial component in building ceramics composite materials are presented in this paper. The slag which is by-product from magnesium production belongs to the four components system Cao-MgO-Al2O3-SiO2. The results of investigation of magnesium production slag alication in the composite materials used for production building ceramics are very important because of its economical as well as ecological aspects. Keywords: Secondary raw materials, slag, composite materials, building ceramics. 26 Institut za ispitivanje materijala a.d. Beograd
A. Prstić, Z. Aćimović-Pavlović, A. Terzić, Lj. Pavlović, Z. Tanasković
THE ALICATION OF BASALT IN CIVIL ENGINEERING 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012, 1153–1158. This paper describes the alication of basalt ores from the mountain of Kopaonik – Serbia for manufacturing different casting materials for civil engineering. Plates made of basalt production by the sand mould casting method. The microstructure characteristics and properties of basalt plates have been tested depending on the parameters of the melting and casting process, the cooling regime and the crystallization of castings. The results of the alication of basalt on frit glaze composition for faience ceramic, described too. Testing was conducted in the aim of finding a correlation for specific characteristics of coating glazes based on basalt, ceramic base, the aearance. Keywords: Basalt, glazes, civil engineering.
A. Prstić, Z. Aćimović-Pavlović, M. Đuričić, A. Terzić, Lj. Pavlović
THE POSSIBILITY OF DIFFERENT FILLERS ALICATION IN COMPOSITION OF REFRACTORY COATINGS 9th Scientific / Research Symposium Metallic and Nonmetallic Materials – production – properties – alication, Zenica, BiH, 2012, 279–285. Results of investigation of ceramic powders alication possibilities in production of coatings for sand molds and cores, as well as the coatings used with other casting methods with alication of meltable and evaporable patterns are presented in this paper. Several coatings compositions were defined. Alication of ceramic fillers (talc, zircon, chromite, corundum) was discussed. In order to attain cost-effective castings production by the Lost foam casting method, it is necessary to obtain the balance in the following system: evaporable polymeric pattern liquid metal - ceramic coating – sand mold during metal inflow, polymeric pattern decomposition and evaporation, castings formation and solidification. Usage of ceramic powders for production of coatings and their alication in the Lost foam casting process decisively depends on the coating rheological properties, i.e. on the suspension sediment stability. Casting process technological parameters significantly influence the structure and the castings Pregled naučnih i stručnih rezultata u 2012. godini 27 properties. Different coating compositions were examined, as well as component preparation and activation methods aimed at attaining homogeneous coating suspension, reduction of coating components precipitation and a coating density reduction. A special attention was paid to detection and analysis of prospective faults, such as porosity, surface non-coverage, coating take-off from the pattern surface or dried coating layer cracking. The aim of the investigation was to establish the correlation between the quality of the castings obtained by different casting methods and the properties of the ceramic coatings alied, i.e. the properties of ceramic fillers. Keywords: ceramic coating, talc, zircon, corundum, chromite, Lost foam process, casting.
A. Terzić, Lj. Pavlović, Lj. Miličić, Z. Radojević
CONSTRUCTION MATERIALS FOR HIGH TEMPERATURE ALICATION BASED ON FLY ASH GTZ 2012 Tuzla: 2nd International Scientific Meeting: State and Trends of Civil Engineering and 2nd Conference Geo-Expo 2012, Tuzla, BiH, 103–110. In this investigation, fly ashes from two different power-plants were subjected to mechano-activation treatment in a planetary ball mill. Mechano-treated fly ashes were mixed with binder. Two different binders were used: standard Portland cement and high-aluminate cement. The investigated fly ash-cement composites were designed to show satisfying performance when submitted to high temperature conditions. Chemical composition analysis and detailed investigation of mineralogical components of cement-fly ash composites are emphasized, due to the fly ash dependence of its origin. Macro-performance of the composites was correlated to the microstructure of fly ash studied by means of XRD and SEM analysis. Thermal stability of crystalline phases was investigated with DTA. Highlight was placed on determination of relationship between fly ash mechano-activation and microstructure on one side and fly ash based products refractory characteristics on other side. Investigated fly ash- cement composites proved to be good thermo-insulators and material for lining for constructive elements of high-temperature furnaces. Keywords: fly ash, cement, high-temperature performance, realication. 28 Institut za ispitivanje materijala a.d. Beograd
A. Terzić, Lj. Pavlović, Lj. Miličić, Z. Radojević, Z. Aćimović Pavlović
SUSTAINABLE SOLUTIONS FOR MANAGING ENVIRONMENTALLY HAZARDOUS WASTE MATERIALS: REALICATION OF FLY ASH 2nd International Symposium on Environmental and Material Flow Management „EMFM 2012“, Zenica, BiH, 167–172. The disposal of the fly ash may pose a significant risk to the environment due to the possible leaching of hazardous pollutants. The only sustainable economic solution for the pollution-prevention of the environment is the reuse of fly ash in building materials. Some of building composites, in which fly ash is combined with refractory components can withstand high temperatures. In this investigation testing composites were based on fly ash mixed with high- aluminate cement. Investigated fly ashes were previously subjected to mechano- activation. The leaching behavior and potential environmental impact of hazardous elements were analyzed. Mineral phase analysis by means of XRD was accented due to the fly ash high dependence on its origin. Crystalline phases were investigated by means of DTA. Scanning electron microscopy was used in microstructure analysis. The leachability of toxic elements was within allowed range, thus investigated fly ashes can be replicated in building materials. Investigated fly ash-cement composites proved to have high physico- mechanical performances, but also good thermo-insulation characteristics. The overall results showed that alication of the fly ash in building composites is sustainable solution for managing this environmentally hazardous waste material. Keywords: fly ash, thermo-insulation, toxic elements, realication, building composites.
A. Prstić, Z. Aćimović-Pavlović, M. Đuričić, A. Terzić, Lj. Pavlović, Z. Tanasković
LININGS BASED CHROMITE FOR ALICATION IN FOUNDRY ModTech 2012, 16th International Conference - New face of TMCR Modern Technologies, Quality and Innovation, Sinaia, Romania, 813–817. Pregled naučnih i stručnih rezultata u 2012. godini 29
In this work, a possibility to develop new chromite-based refractory linings for casting alications has been examined. Lining composition optimization with the controlled reologic properties was achieved by alying different lining components and by alteration of lining production procedure. As filler, chromite was used. The chromite sample was tested by the following methods: X-ray diffraction analysis, diffraction thermal analysis and SEM. The shape and grain size were analyzed by the program package OZARIA 2.5. It was shown that alication of this type of water-alcohol-based lining had a positive influence on surface quality, structural and mechanical properties of the castings of Fe-C alloys obtained by casting into sand molds, according to the method of expandable patterns (Lost foam casting process). Keywords: refractory linings, chromite, sand casting, Lost foam casting process, quality of casting.
M. Ćosić, Z. Aćimović-Pavlović, A. Terzić, M. Dojčinović, Lj. Pavlović
THE POSSIBILITY OF OBTAINING COMPOSITE AL18WT%SI/SIC BY COMPOCASTING PROCESS ModTech 2012, 16th International Conference - New face of TMCR Modern Technologies, Quality and Innovation, Sinaia, Romania, 249–253. The aim of this study was to investigate the influence of various process parameters on the microstructure of composite materials based on alloys Al18Wt%Si with the addition of 10Wt%SiC. The effect of stirring speed (1000 and 1500 rpm), stirring time 15 min and casting temperature 565 oC on the structural and mechanical properties are discussed. It was found that alying the stirring speed of 1500 rpm in semisolid state the best distribution of SiC particles in the matrix was achieved, which gave satisfying mechanical properties. In order to evaluate the quality of obtained composites and their possible alication in the practice, tests were carried out under conditions of cavitation. Cavitation damage to the composite samples was determined using modified vibratory cavitation equipment. Mass loss and surface analysis of composite samples during the experiment were used as an indicator the level of cavitation damage. The results showed very good cavitation resistance which gives the possibility of using these materials in condition where cavitation resistance is needed. 30 Institut za ispitivanje materijala a.d. Beograd
Keywords: Al–Si alloys, composite, composasting process, cavitation resistance.
T. Spasojević-Šantić, M. Arsenović, A. Terzić, Z. Radojević
COMPARATIVE ANALYSIS OF FLY ASH MANAGEMENT IN EUROPE AND SERBIA: ASPECTS AND REGULATIONS Fourth International Congress on Legal-Economic and Ecological Aspects of the Environmental Management in the Chemical, Petrochemical and Oil Industry – CHYMICUS IV, Tara, Serbia, 2012, 1–6. This paper presents a comparative analysis of the fly ash management in Europe and Serbia, as well as its alication the building materials production, with special reference to the existing legislation. The draft development remediation plan is also given, with regard to non conformity with generated and used amount of fly ash and slag. Aim of this paper is to point out the importance of ash used as a replacement for the traditionally building materials, without compromising product quality, while keeping in mind the economic aspect (reducing the amounts of waste ash in landfills), and the aspect of environmental protection.
T. Spasojević-Šantić, G. Dražić, Z. Radojević
PHYTOREMEDIATION OF SOILS CONTAMINATED WITH HEAVY METALS XX International Scientific and Professional Meeting „Ecological Truth“, Eco- Ist'12, Zaječar, Serbia, 2012, 299–305. Heavy metals are among the most widespread pollutants of soil and wider environment. Attention is directed to their toxicity, behavior in the soil and entering the food chain through plants. Phytoremediation is the use of biotechnology, which includes plants for the extraction, sequestration and/or detoxification of pollutants that are present in the soil. Plant species and genotypes are significantly differ in the ability distribution of heavy metals. Therefore, in this paper points is on the different options of phytoremediation, with special emphasis on plant species that are the basis of previous studies Pregled naučnih i stručnih rezultata u 2012. godini 31 have shown good results. Still finding species and genotypes and/or creating them using biotechnological processes can significantly improve the alication of plants in the remediation of contaminated soil with heavy metals. Keywords: phytoremediation, heavy metals, hyperaccumulators, biomass.
D. Perović, T. Spasojević-Šantić
BIOREMEDIATION AND INDOOR AIR QUALITY XX International Scientific and Professional Meeting „Ecological Truth", Eco- Ist'12, Zaječar, Serbia, 2012, 315–320. A large number of analyses of the quality of indoor air indicated that it is very polluted, even dozens of times from the air in the environment, so it aears so- called "sick building syndrome". Bioremediation is biotechnological method to purify the air and to reduce the pollution of indoor air. The aim of study is to highlight the importance of bioremediation of indoor air, with green walls alication and a mixture of microorganisms, in order to improve health and enhance the quality of both residential and working environments. Keywords: bioremediation, microorganisms, green wall, air quality.
A. Abdulrafiu, T. Spasojević-Šantić, B. Eshchanov
THE NIGERIA MINING SECTOR: AN OVERVIEW OF ECONOMIC IMPLICATIONS, ENVIRONMENTAL DEGRADATION AND IMPACT ON CLIMATE CHANGE 34th International Geological Congress (34th IGC), Australia, 2012. This paper examines the role of mining sector in Nigeria economy, environmental degradation and impact on climate change and prescribes a series of recommendations for improving economic and environmental performance in the era of climate change mitigation. Mining sector in Nigeria has over the years, played an important strategic role in the economy. The main factors that come into play are the fiscal contributions and foreign exchange it generates, its role in attracting external investment to the country and its importance for employment. However, because of the fact that mining activities involves mass clearing of forest cover and soil excavation, resulting into vulnerability of most 32 Institut za ispitivanje materijala a.d. Beograd communities in major solid mineral states to impacts of climate change. Structured and non-structured interview were used on a sample of 130 respondents from the study area (80 miners and 30 residents) and 20 respondents from government departments. Field observation was used as well to gather information from the study areas the results showed that there was intensive environmental degradation due to uncontrolled mining in these areas. Thus pose great danger to mitigation and adaptation measures. It is concluded that marked environmental improvements can only be achieved if: (1) assistance is provided to the environmental compliance monitoring agency (NESREA) (2) a nationwide sensitization is continuously conducted (3) the artisanal miners are being organized and (4) report of the 2020 National technical working group on minerals & metals development is well implemented.
S. Dević, M. Cocić
MINERALOGICAL CHARACTERIZATION SUORT IN MATERIAL ALICATION IN CONSTRUCTION AND CERAMICS INDUSTRY 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012, 73 – 77. The aim of this paper is presenting how mineraligical characterization suorts the process of detrmination of nature and quality of some materials that are used also in construction and ceramics industry.The suort is based on results in clay, zeolitic tuff, and slag research. Methodes used in research process are DTA, Midroscopy method in reflected and refracted light, and Electron microscopic method. Depending on sort of materials, different research method are used for mineralogical characterization of materials.
S. Dević, M. Cocić
MIKROSCOPIC DEMONSTRATION EROSION MAGCHROMIC REFRACTORY BRICKS FROM CASTING LADLES BY THE ACTION SLAG XIV YuCorr International Conference „Exchanging experiences in the fields of corrosion, materials and enviromental protection“, 2012, Tara, Srbija. Pregled naučnih i stručnih rezultata u 2012. godini 33
The issue that is treated in this paper refers to the explanation and presentation of erosion magchromic refractory bricks from casting ladle for steel. Erosion magchromic refractory bricks formed by the action of slag was investigated using microscopic methods. Micro-photography are the result of microscopic examination maghromic refractory bricks, using refracted light. They clearly show the erosion of refractory bricks. At the micro-photography shows a gradual penetration of slag in the refractory bricks, its destructive effects and ultimately the destruction of the structure of refractory bricks.
S. Dević, M. Cocić, M. Logar, S. Erić
USING THE ELECTRONIC MICROSCOPE IN THE IDENTIFICATION MINERALS AS A FUNCTION OF MINERAL SULEMENT PREMIX MIXTURES FOR ANIMAL FEED 44 IOC, 44th International October Conference on Mining and Metallurgy, 1-3, Bor, Serbia, 2012, 55-58. The aim of this study was that the alication of electron microscopy confirmed the nature of minerals contained in the premix - mixtures of animal feeds. Mineral identified in the role of mineral sulement premix is clinoptilolite from the group of zeolite. Are used for identification and other available methods such as XRD and DTA, and the results of alication of electron microscopy confirmed the identification of minerals. Electronic microphotography and chemical analysis of selected sites clearly showed the presence of primary minerals clinoptilolite, and less presence of calcite, quartz. After annealing the sample premix and the loss of the organic composition of the premix are expressed characteristic features mineral clinoptilolite. These beautifuly developed forms are shown on the electronic microphotography in this paper.
M. Cocić, M. Logar, M. Pošarac, B. Matović, T. Volkov - Husović, S. Dević, N. Vušović
THERMAL SHOCK PROPERTIES OF GLASS CERAMICS SYNTHESIZED FROM A GLASS FRIT 44 IOC, 44th International October Conference on Mining and Metallurgy, 1-3, Bor, Serbia, 2012, 33-38. 34 Institut za ispitivanje materijala a.d. Beograd
In this study we investigated the behavior of glass ceramics synthesized from a glass frit FFW (final flotation waste) thermal shock testing, in order to discuss the possibility of alication for the production of new material from the group of ceramics (glass ceramic). Thermal shock of the samples was measured using standard laboratory procedure, water quench test. Level of surface deterioration before and during quenching was monitored by image analysis. Ultrasonic measurements were used as nondestructive quantification of thermal shock damage in specimens. Dynamic Young modulus of elasticity and strength degradation were calculated using measured values of ultrasonic velocities obtained by ultrasonic measurements. It was found that materials exhibited good thermal shock resistance, and could be good candidate for alication where this behaviour is required.
K. Đoković, N. Šušić
ESTIMATE LATERAL FORCE FOR LANDSLIDE STABILIZATION BY PILES USING THE ITO – MATSUI’S METHOD 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012, 1985-1990. Estimation of the lateral force is an important factor for the stability analysis,when stabilizing landslide by piles. A reliable method for calculation of the lateral force acting along the piles in a row, when soil between the piles is in plastic equilibrium, is the Ito-Matsui method. The lateral force is determined by this method as the soil impact acting differently on either side of the pile. The results achieved by this method are in this paper. Keywords: Piles, lateral force, landslides, remedial works.
K. Đoković, N. Šušić
DEFINING THE CONDITIONS OF COMPACTION AND BUILDING IN OF CLAYEY SOILS IN CORE OF EARTHFILL DAMS 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012, 1991-1997. Pregled naučnih i stručnih rezultata u 2012. godini 35
Defining the conditions of embedding clay material, compaction and optimum conditions, when making earthfill dams depends directly on the geomechanical properties of the material. Difficulties in the compaction of clayey material are closely related to the size of the consistency index, where there is a dependency relationship of natural water content, plastic limit and liquid limits. This paper analyzes embedding clay materials (CH, CL and CI) obtained based on the results of laboratory tests conducted on samples of clay core earthfill dams : Rovni, Selova, Prvonek and Barje. Keywords: Earthfill dam, compaction, building in.
G. Hadži-Niković, B. Abolmasov, K. Đoković
INTRODUCING LIQUEFACTION POTENTIAL ON SEISMIC HAYARDS MAPS Third International Conference: Seismic Engineering and Engineerings Seismology, Divčibare, 2012, 41-48. For the preparation of hazard maps it is necessary to determine a parameter that allows assessing the liquefaction susceptibility of soil. Because liquefaction hazard maps typically illustrate the hazard of large areas, they are based on surficial geologic maps. Due to based on geologic maps, the liquefaction hazard maps need to assess the degree of liquefaction hazard posed by each geologic unit. There are qualitative geological criteria that assess the liquefaction susceptibility of soil, but not liquefaction manifestations on the surface like: sand boils, ground cracking or lateral spreading. A parameter that permits the assessment of liquefactions performance on the surface, for each geologic unit, is a liquefaction potential index, LPI. Computed from penetration tests and field data and incorporated into a geographic information system (GIS), liquefaction potential index, enhances assessment of liquefaction hazard on the hazard maps. Keywords: liquefaction potential index, liquefaction surface manifestations, seismic hazard maps. 36 Institut za ispitivanje materijala a.d. Beograd
N. Šušić, D. Rakić, K. Đoković, D. Berisavljević
EVACUATION OF WASTE WATERS FROM LANDFILL “SARIĆA OSOJE” – UŽICE 2nd International Symposium on Environmental and Material Flow Management „EMFM 2012“, University of Zenica, Zenica, BIH, 2012, 71-76. The Sarića Osoje landfill of the Užice municipal solid waste is located 3 km NE of the town in a stream valley section 550 metres long. Drain water from the landfill mixing with the stream flows across the town into the Đetinja River. The landfill, in which high groundwater level had been observed, was closed and the tailings since disposed into another, regional landfill. Aware of the threat from groundwater in the old landfill, its drainage has been recommended. Keywords: landfill, geotechnical properties, stability, screen drains .
D. Berisavljević, N. Šušić, Ć. Laslo, K. Đoković
NUMERICAL ANALYSIS OF AXIALY LOADED PILE 2nd International Scientific Meeting: State and Trends of Civil Engineering GTZ 2012 and 2nd Conference GEO-EXPO 2012, Vol.1, Faculty of Mining, Geology and Civil Engineering, University of Tuzla and Geotechnical Society in Bosnia and Herzegovina, Tuzla, BIH, 2012, 517-524. This paper presents a numerical analysis of the pile that was tested using static load test at the construction site of the residential & business complex Stepa Stepanovic in Belgrade. The back analysis of the static load test was performed with the software package Plaxis where the load-displacement curve obtained was matched with the curve obtained during static load testing. In this way it was possible to determine the specific soil parameters required to describe the elastic-perfectly plastic (MC) model. The shaft friction as a function of settlement is evaluated thus obtaining critical settlement values required to develop full mobilization of shaft friction for each layer. All the results are in accordance with literature data. Keywords: Static load test, finite element method, back analysis, shaft friction, critical settlement. Pregled naučnih i stručnih rezultata u 2012. godini 37
N. Šušić, D. Berisavljević, G. Hadži-Niković
EVALUATING SUSCEPTIBILITY OF HETEROGENEOUS TERRAIN TO CYCLIC LIQUEFACTION Third International Conference: Seismic Engineering and Engineerings, Divčibare, 2012, 77-84. Liquefaction is a common earthquake hazard related to ground shaking that accompanies earthquakes, typically magnitude 5.0 or greater. The term liquefaction refers to the physical change that occurs when certain soils are shaken and transformed from solid ground capable of suorting a structure to a quicksand-like liquid with a greatly reduced ability to bear the weight of a building. The paper presents definitions of flow and cyclic liquefaction and procedures for complete assessment of the cyclic liquefaction potential (Robertson, 2010), that means evaluating: susceptibility to cyclic liquefaction, triggering of cyclic liquefaction and post-earthquake deformations. It is also estimated susceptibility of sedimentary deposits to liquefaction for terrain that is composed on saturated cohesive and cohesionless sediments of different deposit age. Keywords: susceptibility to cyclic liquefaction, cohesion and cohesionless saturated soils.
G. Hadži-Niković, N. Šušić, D. Berisavljević
SEISMIC DAMS AND EMBANKMENTS SLOPE STABILITY Third International Conference: Seismic Engineering and Engineering Seismology, Divčibare, 2012, 251-258. Earhquakes produce dynamic loading of slopes, which can reduce the shear strength of soil and lead to instability. In addition, to the complex and comprehensive, often complex and expensive dynamic analyses of the slopes, there are simpler procedures with screening analysis, which can be carried out in order to determine if detailed dynamic analyses are needed in particular case. The paper presents the basic principles of pseudostatic screening stability analyses (Duncan, 2005). In this sense, the quantities: peak ground accelerations, shear strength and shear strength reduction factor, safety factor and tolerable displacement are discussed. It also deals with the postearthquake 38 Institut za ispitivanje materijala a.d. Beograd stability analyses. It stands the shear strength loss during the earthquake and redistribution pore water pressure after earthquake and the impact of their change in postearthquake slope stability. Keywords: pseudostatic screening analyses, undrained shear strength, peak accelaeration, loss of shear strength, redistribution pore water pressure, postearthquake stability analyses.
Ž. Flajs, N. Milovanović, V. Mladenović, Z. Savić
BEHAVIOR OF REINFORCEMENT CONCRETE COLUMN UNDER STATIC LOAD TESTING 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012, 95-102. In order to determine the capacity of reinforced concrete column 110kV electricity network carried out the static load testing and testing until fracture. Testing was conducted on a sample that is built into the high-power network system for more than 30 years. The current high-power network is currently out of use, with the plan to carry out higher loads. Test results were used to determine the column capacity, and ability to accept new designed loads. Keywords: Static load testing, testing until fracture, reinforcement concrete column.
N. Milovanović, Ž. Flajs, B. Ivanković, V. Mladenović
CONDITION SURVEY AND REQUIREMENT TESTS PRIOR TO THE RECONSTRUCTION OF A STRUCTURAL BUILDING 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012, 1287-1294. The aim of the visual inspection and condition survey is to identify defects and deficiencies in structures, and therefore to analyse the condition of the structural building before reconstruction. Condition survey program also includes the subsequent determination of compressive strength of concrete and soil mechanics analysis. Testing load program on the structural building is a very Pregled naučnih i stručnih rezultata u 2012. godini 39 important part of executive works in order to determine compliance with the project when documentation is not available. Keywords: Condition survey, structure condition assessment, testing of structures.
J. Bleiziffer, A. Balagija, T. Landeka, N. Milovanović
CONDITION SURVEY OF CONCRETE STRUCTURES AT PIVA H The 8th Central European Congress On Concrete Engineering – Durability Of Concrete Structures, Plitvice, Croatia, 2012, 197-204. After more than thirty years of exploitation, testing and condition assessment of civil structures was conducted within the project of reconstruction and modernization. Performed works included twelve structures of H: dam body with galleries and shafts inside, stilling basin, intake structure with valve chambers, headrace tunnels, powerhouse and transformer premises, draft tubes, lower surge tank, tailrace tunnel, grouting galleries and 220 kV switchyard. It pertained to assessment of condition of all structures and equipment. Specialist services, rendered by climbers and divers were used and dewatering and cleaning of stilling basin was done to perform the inspections and the tests in areas hard to reach. Keywords: hydropower plant, concrete structures, concrete arch dam, condition survey, testing.
M. Vasić, Z. Radojević
DETERMINATION OF THE OPTIMAL DRYING CONDITION DURING DRYING OF GREEN MASONRY PRODUCTS Modtech International Conference, 2012, Sinaia, Romania. Explanation of the drying process is reduced to the establishment of a series theoretical and empirical drying models. Complex processes of simultaneous mass and energy transfer, which are often non-stationary and the distinct nature and properties of the drying material, complicate even more the description of the drying process. The aim of this study is to find a way to short drying time, to find optimal drying conditions, and to preserve good physical and mechanical 40 Institut za ispitivanje materijala a.d. Beograd characteristics of green masonry products. In order to establish optimal, especially “fast drying” process, it is necessary at the beginning of drying to slowly heat the products while relative humidity within the dryer is kept high. Experimental research was performed in the laboratory recirculation dryer. On the base of laboratory optimization tests, drying process of masonry products in industrial conditions was proposed and optimized. Keywords: optimization, drying, fast drying, masonry product.
G. Petrović, N. Milovanović
PILOT BUILDING AS PART OF REVITALIZATION OF IMS BUILDING TEHNOLOGY IN OSIJEK Scientific conference on planning, design, construction and building renewal INDIS 2012, Novi Sad, 2012. 408-417. This paper presents the alication of the IMS Building Technology in the pilot- building in Osijek, Croatia. Numerous important technical improvements of the system have been implemented. Key differences in comparison to previously used technology include the alication of prestressed tendons system, innovations of elements and joints, production in flexible moulds, innovations of the assembly equipment. Pilot-building was designed according to European Norms. At this moment, IMS structural elements are being produced, and the building itself is under construction. Prefabricated three-layer reinforced concrete façade panels are also featured in the building. Keywords: industrialization of building, IMS Building Technology, prestressing, prefabrication.
D. Nikolić, K. Janković, G. Ćirović
TWO-LAYER RC BEAMS WITH PARTIAL USE OF UHPC 2nd International Scientific Meeting: State and Trends of Civil Engineering – GTZ 2012, No. 1, Faculty of Mining, Geology and Civil Engineering, University of Tuzla, BiH, 2012, 251-258. Ultra high performance concrete (UHPC) as a modern generation of cement composites with extremely high compressive strength, has been subject of many Pregled naučnih i stručnih rezultata u 2012. godini 41 research and shows a very promising future in engineering alications. The use of UHPC in construction is limited by high unit cost. In terms of cost- performance ratio, UHPC can be alied in a part of structure under high compressive stress. This Paper summarizes set of equations for flexural capacity of hybrid two-layer concrete rectangular section beams with UHPC on the compressive side and high strength concrete on tensile side. Two-layer concrete beams can be analyzed using conventional methods for concrete elements. Compatibility conditions between layers is based on the shear deformations equality on the layers border in a section with maximal depth of the compression zone. Experimental examination of mechanical properties of high and ultra high performance concrete is necessary to obtain stress-strain relationship of composites.
K. Janković
SEISMIC BEHAVIOR OF HIGH PERFORMANCE FIBER REINFORCED CONCRETE Third International Conference „Seismic Engineering and Engineering Seismology“, Assosication of Civil Engineers of Serbia, Divčibare, 2012, 289- 294. Evaluation of high performance fiber reinforced concrete is given in this paper. Its properties under load are shown. This type of concrete is ductile, so it found alication in structural elements for earthquake-resistant structures.
G. Ćirović, S. Mitrović, D. Nikolić
OPTIMIZATION OF SHAPE OF ENERGY – SAVING BUILDINGS – PROBLEM FORMULATION 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012, 1777-1784. While buildings and development provide countless benefits to society, they also have significant environmental and health impacts. Building owners, designers and builders face a unique challenge to meet demands for new and renovated facilities that are accessible, secure, healthy, and productive while minimizing their impact on the environment. The object of this work is to 42 Institut za ispitivanje materijala a.d. Beograd determine the optimum dimensions of the shape of a building of volume V and height h, as well as the minimum yearly heating costs. Constraints of optimization problem are also defined.
K. Janković, Lj. Miličić, D. Nikolić, D. Bojović, Lj. Lončar
INVESTIGATION OF THE MORTAR AND CENCRETE RESISTANCE FOR AGRICULTURAL STRUCTURES 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012, 147-152 Concrete in the agricultural structures is exposed to aggressive influence. Resistance on corrosion caused by carbamide, lactic and acetic acid was presented in this paper. The chemical resistance of mortar and concrete was tested according to the Koch-Steinegger method. As a condition for resistance in aggressive solution means that flexural strength of mortar prisms no less than 70% of referent prisms cured in water it can be concluded that combination of cement and additive presented in this investigation is not satisfied for agricultural structures.
A. Mitrović, D. Nikolić, Lj. Miličić
CONTRIBUTION TO THE SUSTAINABLE CEMENT PRODUCTION BY USE OF METAKAOLIN OR AMORPHOUS KAOLIN 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012 1117-1123. Metakaolin (MK) was obtained by thermal treatment and amorphous kaolin (AK) by mechanochemical treatment of the same kaolin clay from Aranđelovac basin. They are used for the partial replacement of cement in composite Portland-cemet. The compressive strength of the cement (CEM II), with addition of 5 – 35 % by mass of MK, AK and commercial metakaolin (CMK) after 2, 7 and 28 days of curing, were compared with the strength of Portland cement (CEM I) used as reference cement. The strengths greater than the reference cement, after 7 and 28 days, were obtained with addition up to 20% of MK or with 5% of AK. Pregled naučnih i stručnih rezultata u 2012. godini 43
Keywords: Metakaolin, amorphous kaolin, composite Portland-cement.
D. Nikolić, K. Janković, A. Mitrović, D. Bojović
MECHANICAL PROPERTIES OF ULTRA NIGH PERFORMANCE CONCRETE AT ELEVATED TEMPERATURES 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012, 1125-1132. This paper presents the effect of thermal curing on mechanical properties of ultra high performance steel fiber reinforced concrete (UHPSFRC). Compressive and flexural strength were measured on two series of concrete with different mineral admixtures. The samples were exposed to different curing regimes (standard water curing, steam curing on 95°C and autoclaving at 8bar and 20bar). The compressive strength varied between 165MPa and 215MPa for the steam cured and autoclaved specimens and between 135 and 150 MPa for the hadn’t been heat treated samples after 28 days. Furthermore, this paper presents SEM micrographs of C-S-H phase formed after steam curing and autoclaving. Keywords: Ultra high performance concrete, steel fiber, steam curing, autoclaving.
G. Petrović, V. Petrović
SKADARLIJA AND THE OLD BREWERY – URBAN RECONSTRUCTION CASE STUDY New Urbanity: Cities vs. Global Challenges, Belgrade, 2012, 382-389. Skadarlija is a famous ‘bohemian’ street in Belgrade city centre. Once a lively romantic quarter, it is slowly turning into a fake scenery for elderly tourist groups. Several years ago, an international real estate company bought the adjacent old brewery complex, and the largest part of Skadarlija street frontage with it. This paper gives an analysis of present spatial and social conditions, prepared to serve as a basis for further work on urban reconstruction of the whole location. The aim of this analysis was to recognize and clearly define new values and contemporary social relations, as well as to point out different 44 Institut za ispitivanje materijala a.d. Beograd possible design aroaches to this task. As none of this has been implemented, this is also a sad story about a deserted premium location, empty shops and restaurants, building heritage and historical artefacts left to decay and disintegration – basically, a story of the end of romantic bohemian lifestyle.
B. Ivović, I. Delić-Nikolić, L. Kurešević
UZROCI PROPADANJA I MOGUĆNOSTI ZAŠTITE GROBNICE ILIJE MILOSAVLJEVIĆA KOLARCA U BEOGRADU 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012, 1177-1185. Spomen grobnica Iliji Milosavljeviću Kolarcu 1789-1878 trgovcu i velikom narodnom dobrotvoru je izgrađena od tamno sivog do mrko crnog kamena. U pitanju je veoma kompaktna, homogena i sitnozrna magmatska intruzivna stena-gabro. Veći deo poliranog kamena, koji se nalazi na površini spomenika je u stanju korozije i intenzivne degradacije. Poznato je da se predmetni kamen odlikuje izuzetno dobrim fizičko mehaničkim osobinama i svojstvima postojanosti. Zato je njegova intenzivna destrukcija veoma neuobičajena. Jedan od glavnih razloga za njegovo ubrzano propadanje je najverovatnije nestručna prethodna restauracija i konzervacija.
D. Rakić, N. Šušić, M. Ljubojev
ANALYSIS OF FOUNDATION SETTLEMENT FROM PROGRESSIVE MOISTENING OF SILTY CLAY Mining Enginerering - Rudarski radovi, Mining and metallurgy institute Bor, No 1/2012, 2012, 1-10. Examples of visible damage (cracks on the face walls) on the shallow founded older buildings in Belgrade are not rare. Usually, this is a consequence of unequal settlement resulting from unexpected moistening of soil under foundations. Moistening usually occurs locally and in such conditions differential settlement is inevitable. This paper presents research results, which indicate that besides the size of the zone of moisture change in soil in horizontal direction and calculated settlement values, total change of the volume of soil under foundations should be analyzed. Pregled naučnih i stručnih rezultata u 2012. godini 45
Keywords: soil moistening, settlement, static penetration, volume change.
D. Berisavljević, N. Šušić
GEOTECHNICAL FIELD INVESTIGATIONS FOR THE NEW BRIDGE OVER DANUBE AT BESKA 5th International Conference Science and Higher Education in Funcion of Sustainable Development SED 2012, Uzice, 2012, 3-7. Bridge over the Danube river at Beška is one of the most important infrastructural objects in Serbia. In 2009 field investigations have been carried out in order to determine the spatial position of slip surfaces and the depth of the existing diaphragm on the right bank in the area of the old bridge over Danube at Beska. A great contribution on the results had excavation of five exploratory shafts. Data obtained from them are essential for rational landslide remediation. The new bridge was opened for traffic in october 2011. Keywords: slip surface, diaphragm, geotechnical field investigations, exploration shaft.
V. Grabulov, A. Vukosavljević, Z. Odanović, M. Arsić
INVESTIGATION OF REPAIR WELDING TECHNOLOGY FOR DISSIMILAR STEEL JOINTS ON A HYDRO POWER PLANT TURBINE PARTS 8th European Conference - Eurojoin 8, European Federation for Welding, Joining and Cutting & Croatian Welding Society, Pula, Croatia, 2012, 393-404. After 40 years of service а revitalization of turbines in hydro power plant „Djerdap“ on Danube River in Serbia has been performed. New welding technology had to be developed for different components on hydroelectric rotor and turbine, including dissimilar welded joints. Performed investigations are presented in this paper. Special care had been devoted to design of welding technology, defining process parameters and selection of electrodes. The parent metals, alied in this investigation, were structural C-Mn steel (GOST St 3) and stainless steel X10 Cr Ni Mo Ti 18-10. For the repair welding a SMAW (111) welding process is selected and two basic austenite covered electrodes were 46 Institut za ispitivanje materijala a.d. Beograd analyzed. The first one was electrode of 18-8-6 class, E 18 8MnB22 (EN 1600). The second electrode was ЭA-395/9 according GOST 9466-750 (ISO E16.25.6B2). A series of trial welds with different welding heat input and preheating temperatures were used in this investigation. Tensile tests, impact energy tests, bend tests and hardness of welded joint cross-section measurements were performed on trial joints. Sensibility tests for hot, cold and lamellar cracks occurrence as ”Fisco”,”CTS”, ”Y” and Z-window tests were alied for chosen electrodes at different welding conditions. Special attention was alied to the sensitivity to lamellar cracks forming, due to the fact that the strengthening parts were perpendicularly welded to turbine structural material, as strengthening ribs. Based on the analysis of the results, optimal welding technology was chosen. Keywords: dissimilar steel joints, repair welding technology, austenite electrode, weldabillity assessment, hot cracks, cold cracks, lamellar tearing.
M. Arsić, S. Bošnjak, Z. Odanović, V. Grabulov, B. Vistać
INFLUENCE OF PLASTICITY REDUCTION ON STRENGTH AND FRACTURE OF TURBINE RUNNER COVER IN HYDRO POWER PLANT DJERDAP 1 First International Conference on Damage Mechanics - ICDM, Belgrade, Serbia, 2012, 57-60. Vertical Kaplan turbines, with 200 MW of nominal output power, manufactured in Russia, are built into six hydro-electric generating units of hydro power plant „Đerdap 1”. In this paper results of experimental examinations of four specimens taken from the runner cover which is made of cast steel 20GSL are presented. These results indicated that values of yield strength, tensile strength and impact energy for all specimens met the demands of the standard, while two specimens had significantly lower values of elongation (A5 = 8% and 9%). Taking into account that values A5 i Z are not universal and the fact that it is impossible to estimate whether fracture mechanism will be implemented in material the runner cover was made of, analytical and numerical calculations of stress state and experimental examinations of fracture mechanics parameters have been carried out. Obtained results of fatigue crack growth rate da/dN indicated that internal deformations of circular or elliptical shape (flaws Pregled naučnih i stručnih rezultata u 2012. godini 47 detected by ultrasonic testing), of initial size up to 6 mm, enable 29 year long reliable operation of the runner cover. Keywords: hydro turbine, runner cover, plasticity, life.
R. Rakin, B. Međo, M. Arsić, Ž. Šarkoćević, V. Grabulov, A. Sedmak
DAMAGE AND FAILURE ASSESSMENT OF PIPES WITH LOCAL THIN AREAS First International Conference on Damage Mechanics - ICDM, Belgrade, Serbia, 2012, 281-284. The subject of this study is alication of local aroach to ductile fracture in order to estimate the integrity of pipes with local thin areas (e.g. corrosion defects). Majority of the procedures for determining the load carrying capacity of such structures are based on limit loads, i.e., plastic collapse criteria. However, they can also fail by ductile fracture mechanism, which is modelled in this work using the complete Gurson model - CGM. This model is alied to predict the damage development in the pipes with simulated corrosion defects (machined notches with different sizes). The failure criterion is considered fulfilled when damage parameter reaches its critical value in the bottom of a notch. Bearing in mind that one of the main problems in alication of local aroach to fracture is the mesh sensitivity, a study has been conducted to determine the dependence of maximum pressure on the size and formulation of the finite elements in the defect area. Keywords: pipes with local thin areas, complete Gurson model, failure criterion, mesh dependence.
M. Rakin, M. Arsić, Ž. Šarkoćević, B. Međo, N. Tomović, A. Sedmak
DAMAGED WELDED PIPES FOR OIL AND GAS RIGS EXPOSED TO INTERNAL PRESSURE - FAILURE ESTIMATION 19th European Conference on Fracture - ECF 19, Fracture Mechanics for Durability Reliability and Safety, European Structural Integrity Society – ESIS, Kazan, Russia, 2012, 1-7. 48 Institut za ispitivanje materijala a.d. Beograd
The paper deals with the integrity assessment of API J55 steel casing pipes for drilling rigs, manufactured by high frequency contact welding procedure. The influence of corrosion defects on the pipeline load carrying capacity is determined through pressure test of a pipe with corrosion damages simulated by machining the circular holes. Finite element analysis of the damaged pipe subjected to internal pressure is used for determining the stress/strain conditions in the damaged area of the pipe. Also, numerical model was used for establishing the load carrying capacity of the pipe with different damage levels (i.e. defect depth and length). Several expressions from the literature are used for estimation of the maximum pressure in the damaged section of the pipe, and the solutions are compared with the predictions of finite element models and experimental results. Keywords: Casing pipe, Surface defect, Maximum pressure, Finite element analysis.
M. Arsić, S. Bošnjak, M. Rakin, N. Gnjatović, Z. Savić
RELIABILITY ASSESSMENT OF WELDED JOINTS AT PARTS OF VITAL STRUCTURES OF BUCKET - WHEEL EXCAVATORS BASED ON HYPERGEOMETRIC DISTRIBUTION OF DEFECTS XX International Conference on Material handling, constructions and logistics - MHCL ’12, Belgrade, Serbia, 2012, 155-160. In order to reduce costs of tests that need to be carried out on structural welded joints and losses in the production due to excavator standstill, a new method for reliability assessment of welded joints during exploitation of bucket-wheel excavators has been developed. In this paper a part of non-destructive testing results for the butt welded joints at bucket-wheel, discharge and counter-weight boom structure is presented, prior to the repair of the heavily damaged bucket- wheel excavator Sch Rs 1760x32/5. It has been in operational mode for 17 years prior to the collapse, in other words it has been subjected to 2.125.000 cycles of variable loading. For the calculation of probability that x welded joints would be selected out of overall Q, which comprise n welded joints with defects, hypergeometric distribution has been used, while the reliability assessment for welded jointed structures of bucket-wheel excavators has been performed on the basis of defect analysis and probability of the growth of Pregled naučnih i stručnih rezultata u 2012. godini 49 fatigue cracks in welded joints. Through the use of this method testing costs have been reduced by 70 %. Keywords: bucket-wheel excavator, welded structure, experimental tests, single selection method, reliabilit.
M. Arsić, S. Bošnjak, B. Međo, M. Burzić, B. Vistać, Z. Savić
INFLUENCE OF LOADING REGIMES AND OPERATIONAL ENVIRONMENT ON FATIGUE STATE OF COMPONENTS OF TURBINE AND HYDROMECHANICAL EQUIPMENT AT HYDROPOWER International Conference Power Plants 2012, Zlatibor, Serbia, 2012, 1-10. Horizontal Kaplan turbines, were installed in 10 generating sets units at „DJERDAP 2“. After 163.411 hours of operation, the fracture of the hydro- electric generating set A6 turbine shaft in the area of high stress concentration occurred, at the transition radius between the flange and the runner hub. In this paper the results of the analytical calculation regarding the strength of the turbine shaft are presented and influence of the corrosive environment, as well as tests regarding the fatigue. Tensile tests under constant amplitude loading were carried out on smooth specimens in order to determine fatigue properties of the base material, as well as bending tests on notched specimens in order to determine fracture mechanics parameters, or correlation between the crack growth rate da/dN and the stress intensity factor ΔK. It has been established that stress values were higher than allowable values, which led to the occurence of many cracks due to fatigue corrosion. One of those cracks caused the fracture. Keywords: turbine shaft, stress concentration, corrosion, fatigue, crack.
J. Bernetić, M. Marčetić, G. Kosec, T. Vuherer Z. Burzić, D. Jaković, M. Rimac
BALLISTIC INVESTIGATION BY W – CARBIDE AMMO ON THE ARMOUR PROTECTION STEEL – PROTAC 500 5th International Scientific conference on defensive technologies „Oteh“, Belgrade, Serbia, 2012, 1–6. 50 Institut za ispitivanje materijala a.d. Beograd
The ballistics testing results according to VPAM APR 2007 are represented in this work. Ballistic testing was done using .308 Win 7.62 x 51 FMJ/FB/WC ammunition. Two different cartridges from the producer Nammo AP 8 and Ruag SWISS P AP were used. Both types of ammunition have tungsten carbide core. Damage – craters, done by the projectiles, were cut and analyzed over the transverse section by optical and scanning electron microscope. The EDS analyses of the characteristic areas were also done.
A. Prstić, Z. Aćimović-Pavlović, A. Terzić, Lj. Pavlović
SYNTHESIS OF NEW TYPE OF CORDIERITE COATINGS Physical Chemistry 2012: 11th International Conference on Fundamental and Alied Aspects of Physical Chemistry, Vol. 1, Belgrade, Serbia, 2012, 435-437. New refractory coatings based on synthesized cordierite for the casting alications were investigated. The investigation included synthesis of the cordierite and design of the refractory coating as final product. Design and optimization of the coating composition, with controlled rheological properties included, were achieved by alication of different coating components, namely different suspension agents and by alteration of the coating production procedure. Cordierite, used as filler, was obtained by means of synthesis in the solid state reaction on the basis of talc, kaolin and alumina. The investigation showed that the alication of these particular types of coatings has positive influence on surface quality, structural and mechanical properties of the castings of aluminum alloys. Keywords: refractory coating, cordierite, synthesis.
A. Terzić, Lj. Pavlović, J. Stojanović, Z. Radojević
REFRACTORY COMPOSITES BASED ON WASTE MATERIAL: XRD INVESTIGATION OF PHASE CHANGES WITH TEMPERATURE 44th International October Conference on Mining and Metallurgy, Tehnicki fakultet Bor, Institut za rudarstvo i metalurgiju, Bor, Serbia, 2012, 259-264. Refractory composites based on waste material were investigated. Two composite mixes were prepared as follows: (1) 70 % of standard Portland Pregled naučnih i stručnih rezultata u 2012. godini 51 cement and 30 % of fly ash originating from coal combustion; (2) 70 % of high- aluminate cement and 30 % of fly ash. Fly ash was previously mechano- activated. The phase changes of the composites influenced by increasing temperature were investigated by means of XRD. The addition of fly ash decreased sintering temperature, but excellent composite thermal resistance maintained unchanged. XRD showed that crystallinity of composites improved with increasing temperature. The formation of rankinite, gehlenite, anorthite and cristobalite in contributed to thermal stability of composites. Keywords: XRD, fly ash, thermal behavior, cement, recycling.
D. Jevtić, A. Mitrović, D. Zakić, B. Ilić
THE INFLUENCE OF METAKAOLIN AS PARTIAL REPLACEMENT OF CEMENT ON MORTAR AND CONCRETE PROPERTIES 19. Slovenski kolokvij o betonih: Doseganje Posebnih Lastnosti Betonov z Uporabo Odpadnih Materialov, Ljubljana, 2012, 41-50. This paper deals with the properties of mineral materials which may be used as partial replacement of cement and their influence on properties of cementitious composite materials – mortar and concrete. The use of by-products like fly ash, granulated blast furnace slag, silica fume, rice husk ash and metakaolin in cement based composites has recently gained significant importance due to the growing requirements in the fields of environmental protection and sustainable construction. Some of the research results obtained during testing of composite materials made with commercial metakaolin, but also with domestic metakaolin types made in Serbia, are presented and discussed. These results indicate that the addition of metakaolin generally contributes to higher compressive strength, reduction of shrinkage and improvement of freeze-thaw resistance of cementitious composites. Keywords: cement, mortar, concrete, mineral materials, metakaolin, cement replacement, research, sustainable construction. 52 Institut za ispitivanje materijala a.d. Beograd
Z. Radojević, M. Arsenović, A. Terzić, N. Vuković
INVESTIGATION OF THE NATURE AND CAUSE OF DEFECTS ON VISIBLE SURFACE OF CERAMIC TILES EMBEDDED ON FAÇADE OF A FACILITY Scientific conference on planning, design, construction and building renewal INDIS 2012, Novi Sad, 2012. Results of the investigation and specific testing on the visible surface of ceramic tiles are presented in this paper. The investigation was conducted with the goal to determine the nature and cause of defects aearing on the glazed tiles. Glazed ceramic tiles, sizing 120 x 60 cm, were previously embedded on façade of the „Banja Komerc” facility in Aranđelovac. Influenced by atmosphere, certain defects aeared on visible surface of glazed ceramic tiles. Defects were shaped as dark-brown dots surrounded by yellow halo. Investigation was conducted on the tiles which were previously embedded on the façade, as well as on the ceramic tiles from the package, which were not embedded nor installed in any other way. With an aim to obtain answer on the question of defects origin, investigation has been conducted in accordance with standard SRPS ISO 10545: determination of dimensions and surface quality; determination of moisture expansion; determination of chemical resistance; and determination of resistance to stains. Also, microstructural analyses were conducted by means of optical microscope and scanning electron microscope (SEM) coupled with energy dispersive spectrometer (EDS) device. Analysis of the obtained results highlighted possibility of defects cause being carbon and iron as impurity, both present in raw material used for glaze production. Keywords: ceramic tiles, glaze, defects, impurities, microstructural analysis.
V. Aleksić, Z. Kovačević
TESTING OF UER RING OF GUIDING AARATUS DURING REVITALIZATION OF A6 AGGREGATE AT HE DJERDAP 1 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012, 1255-1261. In present paper, rejection of the uer ring of the guiding aaratus (URGA) during revitalization of the A6 aggregates at HE Djerdap 1 has been presented. Pregled naučnih i stručnih rezultata u 2012. godini 53
Rejection was conducted after 37 years of exploitation based on the decisions made after testing, both NDT and DT, and unsuccessful recovery using various welding technologies.
V. Aleksić, Lj. Milović, Z. Kovačević
THE FAILURES OF A SUORTING STRUCTURE OF A COAL- RELOADING BRIDGE AND METHODOLOGICAL AROACH TO RECOVERY OF THE DAMAGES The 7th International Symposium „KOD 2012“, Balatonfüred, Hungary, 2012, 105-108. In present paper, methodological aroach to the analysis of the failures and recovery of the damages has been presented on an example of fracture and damage of a structure of the reloading bridge. The aroach presented can be alied to various types of similar structures, and its alication in preventive maintenance would contribute to extension of exploitation life of the reloading bridges.
Z. Kovačević, Z. Karastojković, V. Aleksić, Z. Janušević
MICROSTRUCTURE ANALYSIS AND CRACK DETECTION IN TURBINE BLADES AFTER PROLONGED EXPOSURE IN PLANT The 7th International Symposium „KOD 2012“, Balatonfüred, Hungary, 2012, 507-510. Turbine blades are one of the most important machine parts in every power generator. Corrosion and/or erosion attack on blades are also available in moisture atmosphere, because the wet water vapour is an usual working media in low pressure turbine. After long time in service, the initial structure is changed. Some pores were metallographically detected and their aggregation combined with probable coagulation around non-metallic inclusions is observed. Those pores can lead to the crack formation. Serious problems may arise due to these non-metallic inclusions since they are surrounded by a number of individual pores or even characteristic “clouds” of pores are formed around inclusions. From the aspect of blade vibrations, the crack will be expected only at some positions. This kind of crack usually is initiated at the 54 Institut za ispitivanje materijala a.d. Beograd blade surface. In another case, when an aggregation process of pores occurs, the coagulation and coarsening of pores may provoke the crack initiation not on the surface, but in the bulk of the blade material. Metallographic investigations were performed using light microscope.
J. Ćirilović, N. Vajdić, G. Mladenović, C. Queiroz
DEVELOPMENT OF A PREDICTION MODEL FOR THE UNIT COST OF ROAD REHABILITATION AND RECONSTRUCTION 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012, 2319-2326. Cost estimations with a satisfactory level of accuracy at the planning stage of road network rehabilitation and reconstruction are perceived as one of the most influential factors to the success of such programs. In order to ensure stable financing during the realization of the project it is important to estimate the costs as accurately as possible in early stages, when minimum project information is available. In this paper an effort is made to develop a cost prediction model using limited project information which is alicable to a wide range of projects in different countries. Keywords: Cost estimations, road rehabilitation and reconstruction projects.
J. Ćirilović, N. Vajdić, G. Mladenović, C. Queiroz
DEVELOPMENT OF PREDICTION MODELS FOR THE COST OF ROAD WORKS USING MULTIVARIATE REGRESSION ANALYSIS EPAM, Malmo, Sweden, 2012. The average unit costs of road works vary substantially between countries, and even between projects in the same country, due to a number of factors. In this paper an effort is made to develop prediction models for the unit costs of road works that could be alied for a wide range of conditions in different countries. A specialized dataset is used, which was generated under a World Bank study for a sample of road works contracts from 14 countries in Europe and Central Asia (ECA). The data sample covers 200 completed or on-going road works contracts signed between the years 2000 and 2010. The database classifies road Pregled naučnih i stručnih rezultata u 2012. godini 55 work activities into the following categories, commonly found in the contracts included in the study: rehabilitation/reconstruction, new construction, asphalt pavement overlays and periodic maintenance. A multivariate regression analysis is used to evaluate the determinants of the cost per km of the above road works. The dependent variable is the actual cost per km of the specific road work. The explanatory variables that are tested in the model include variables related to oil prices, variables that are country specific, a variable indicating the climate conditions and variables that are project specific. The important factors that contribute significantly to the regression equations are highlighted. The variables included in the analyses were chosen in view of their potential explanatory power. The resulting regression equations are expected to be useful in the strategic analysis of road networks, including the optimization of road maintenance and rehabilitation where specific project data is very limited.
J. Ćirilović, N. Vajdić, G. Mladenović, C. Queiroz
PREDICTION MODEL FOR THE COST OF ROADREHABILITATION AND RECONSTRUCTION WORK Second International Conference on Road and Rail Infrastructure, Croatia, 2012, 389-395. Maintenance of existing road network represents a challenge for public road authorities who seek a balance between available budgets and the need for maintaining level of service at a satisfactory level on existing road sections. For this reason, prediction of cost for road rehabilitation and reconstruction works represents one of key inputs for the objective analysis of projects and available budgets and optimization of road maintenance alternatives. However, the average unit costs of road rehabilitation and reconstruction vary substantially between countries, and even between projects in the same country, due to a number of factors. In this paper an effort is made to develop a prediction model that could be alied for a wide range of conditions in different countries. A specialized dataset is used, which was generated under a World Bank study for a sample of road works contracts from 14 countries in Europe and Central Asia, signed between the years 2000 and 2010. The data sample for the analysis covers 94 projects of rehabilitation and reconstruction of flexible pavements. A multivariate regression analysis is used to evaluate the determinants of the cost 56 Institut za ispitivanje materijala a.d. Beograd per kilometer of the road rehabilitation or reconstruction. The explanatory variables that are tested in the model are divided in three groups: variables related to oil prices, variables that are country specific and variables that are project specific. The variables included in the analyses were chosen in view of their potential explanatory power. The resulting regression model is expected to be useful in the strategic analysis of road networks, including the optimization of road maintenance alternatives. Keywords: Road rehabilitation and reconstruction works, cost prediction model, multivariate linear regression analysis.
G. Mladenović, J. Ćirilović
PERFORMANCE OF ASPHALT MIXTURES WITH INCREASED RECLAIMED ASPHALT PAVEMENT (RAP) CONTENT 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012. Recycling of an asphalt pavement makes both environmental and economic sense. RAP rates between 10 and 20% are commonly used in asphalt mixes and according to previous studies, asphalt mixtures with these RAP rates perform similarly to conventional mixtures. The use of higher RAP rates, up to 50 %, would lead to more sustainable pavement structures with lower energy and natural resources consumption, having also positive effects from the economic point of view. The research presented in the paper shows improved moisture susceptibility and rutting performance of asphalt mixes with RAP contents of 15% and 30%. Keywords: asphalt mixes, reclaimed asphalt pavement, moisture susceptibility, rutting. Pregled naučnih i stručnih rezultata u 2012. godini 57
SAOPŠTENJE SA MEĐUNARODNOG SKUPA (M34)
A. Terzić, Lj. Pavlović, N. Obradović, V. Pavlović, Z. Radojević, Lj.Miličić, Z. Aćimović-Pavlović
EVALUATION OF FLY ASH PYSICO-CHEMICAL CHARACTERISTICS AS COMPONENT FOR ECO-CERAMIC AND SINTERED MATERIALS Advanced Ceramic and Alication, Sebian Ceramic Society, Belgrade, Serbia, 2012, 32. The aim of the presented study is to evaluate utilization potential of the fly ash which is the main residue from the coal combustion thermal-plants. Decades long high production of fly ash represents extreme hazard for the environment. The storage problem of this waste material is also alerting. Thus, recycling and realication of fly ash in construction materials industry is the only economic solution. The well-knows examples of fly-ash realication as a component in cement, mortar, concrete, bricks and tiles are not enough in means of reusing extreme amounts of this waste material. Therefore, new alications in ash-based composites have to be developed: eco-ceramic materials and sintered materials for refractory performances. In this investigation, characterization of three different fly ash capacities was used as base for further fly ash utilization possibilities analysis. Accent was on the investigation of the fly ash mineralogical and chemical composition. Thermal stability of crystalline phases was investigated with DTA. Macro-performance was correlated with the microstructure of fly ash studied by means of XRD and SEM analysis. Furthermore, content of trace elements, physico-chemical characteristics and leaching toxicity tests were carried out. Comparing the properties of investigated fly ashes with standard values, it could be presumed that fly ash originating from Serbian power plants can be potentially useful for high value products - eco-ceramic and refractory/sintered materials manufacturing. Keywords: fly ash, microstructure, potential reusing, eco-ceramic, sintering. 58 Institut za ispitivanje materijala a.d. Beograd
A. Prstić, Z. Aćimović-Pavlović, A. Terzić, Lj. Pavlović
THE PRINCIPLES OF CHOICE OF REFRACTORY COATINGS USED IN LOST FOAM CASTING PROCESS Advanced Ceramic and Alication, Sebian Ceramic Society, Belgrade, Serbia, 2012, 33. For production of the castings with favorable properties refractory coatings with the advance quality setting must be used. During the casting, the basic role of coating is creation of an efficient refractory barrier between sandy substrate and liquid metal flow. The coating properties required (refractoriness, favorable gas permeability, easy alication and adhesion to sand mold surfaces and polymer model surfaces in the Lost foam casting process, easy adjustment of thickness of the coating layer, high drying rate without cracking or removal of the dried coating layers) were achieved by optimization of coating composition and their production technology. As refractory coating fillers, cordierite, talc, mica, zircon and mullite were chosen due to their properties: (1) low heat spread coefficient; (2) relatively high melting temperature; (3) no soaking up with liquid metal; (4) no gas production when in contact with liquid metal. The sediment stability of coating suspension is an important coating property. Different kinds and quantities of additives were tested, as well as their activation procedures, with an aim to enable easy additive absorption to the refractory filler particles, maintenance of the filler in a dispersed state and prevention of the filler building up. Bonding agents within the coating was chosen in regard to the size and shape of the refractory filler particles and in order to enable connection between the particles and to secure good adhesion of refractory particles to the observed surface of either the sandy mold or polymer model. Alcohol was used as a liquid solvent, as well as water. It was concluded that the optimal density of refractory coating was 2 g/cm3. Keywords: refractory coating, Lost Foam casting process, quality of castings, high temperature material. Pregled naučnih i stručnih rezultata u 2012. godini 59
A. Terzić, Lj. Pavlović, Z. Aćimović-Pavlović, N. Obradović
MICROSTRUCTURAL CHANGES IINITIATED BY SINTERING OF REFRACTORY CONCRETE BASED ON RECYCLED BAUXITE AGGREGATE 3rd International Samsonov Memorial Conference „Materials Science of Refractory Componds“, Kyiv, Ukraine, 2012, 73. Concretes whose structure and final properties are shaped during thermal pre- treatment or during life-service at elevated temperatures can be alied as construction material for thermal insulation and/or refractory linings in high- temperature-operating plants. Refractory concretes designed with waste raw materials show satisfying performances in comparison with standard concretes. Sintering initiates microstructural changes within concrete. Concrete microstructure further develops with increasing temperature. Change progression can be monitored by means of destructive and non-destructive tests: either by investigating change of compressive strength or aarent porosity of concrete samples. Destructive tests, in this study, were alied in compressive strength investigation, while non-destructive tests were performed for results comparison. Experiment has been conducted on corundum (standard) concrete and recycled bauxite (experimental) concrete. Samples underwent thermal treatment from 110 to 1500 ºC. Macro-performance of the final refractory concrete was correlated to the microstructural change detected by means of XRD and SEM analysis. Creep testing was conducted to prove sintering process. Results showed that recycled concrete has equal if not better properties in comparison with standard refractory concrete and can be used as thermo- insulation or refractory material. Keywords: refractory concrete, sintering, microstructural change, image analysis, recycling.
A. Terzić, Ljubica Pavlović, Nina Obradović, Vladimir Pavlović, Ljiljana Miličić, Z. Radojević
SYNTHESIS AND SINTERING OF FLY ASH BASED COMPOSITES FOR HIGH TEMPERATURE ALICATION 3rd International Samsonov Memorial Conference „Materials Science of Refractory Componds“, Kyiv, Ukraine, 2012, 60. 60 Institut za ispitivanje materijala a.d. Beograd
Fly ash, as the main residue in coal combustion in thermal-plants, represents extreme hazard for the environment. Recycling and realication of fly ash in building materials industry proved to be the only economic solution for the on- going problem with air, water and soil pollution. In present study, fly ashes from two different landfills were subjected to mechano-activation treatment in a planetary ball mill, and the treated fly ashes were cemented with a binder. Two different binders were used: standard Portland cement and high-aluminate cement. The goal of the investigation was to obtain fly ash-cement composite with satisfying performances for high temperature alication. Chemical composition analysis and detailed investigation of mineralogical components of cement-fly ash composites are emphasized, due to the fly ash dependence of its origin. Macro-performance of the composites was correlated to the microstructure of fly ash studied by means of XRD and SEM analysis. Furthermore, thermal stability of crystalline phases was investigated with DTA. Highlight was placed on determination of relationship between fly ash mechano-activation and microstructure on one side and fly ash based products refractory characteristics on other side. Keywords: fly ash, refractory compounds, cement, high-temperature performance, recycling.
A. Prstić, Z. Aćimović-Pavlović, A. Terzić, Lj. Pavlović
REFRACTORY LININGS BASED ON MULLITE FOR ALICATION IN FOUNDRY 3rd International Samsonov Memorial Conference „Materials Science of Refractory Componds“, Kyiv, Ukraine, 2012, 74. Various possibilities for the development of the new mullite-based refractory linings which can be alied in casting process were investigated and presented in this paper. Optimization of the refractory lining composition design with the controlled reologic properties was achieved by alication of different lining components and by alteration of lining production procedure. Mullite was used as a high-temperature filler. The mullite sample was tested by the following methods: X-ray diffraction analysis, diffraction thermal analysis and scanning- electron microscopy. The shape and grain size were analyzed by the program package for image analysis OZARIA 2.5. It was proved that alication of this type of water-alcohol-based lining had a positive influence on surface quality, Pregled naučnih i stručnih rezultata u 2012. godini 61 structural and mechanical properties of the castings of Fe-C alloys obtained by casting into sand molds, according to the method of expandable patterns (Lost foam casting process). Keywords: refractory lining, sintering, microstructural change, image analysis, mullite, Lost foam casting process.
M. Arsenović, L. Pezo, Z. Radojević
CLAY BRICK COMPRESSIVE STRENGTH AND WATER ABSORPTION PREDICTION USING NON-LINEAR REGRESSION AND ANN Advanced Ceramic and Alication, Serbian Ceramic Society, Belgrade, Serbia, 2012, 13 (S 2.6). Heavy clay samples used in this research were collected at 84 locations in Serbia. The effects of chemical composition, various firing temperatures, and several shape format of laboratory samples on the compressive strength and water absorption were investigated in this paper. Prediction of compressive strength and water absorption was done by non-linear regression analysis and five artificial neural networks. Analysis of variance showed significant effects (p<0.05) of all processing factors. The statistical comparison methods such as r2, χ2, MBE and RMSE were used to explore the confidence level of the models. Developed models were able to predict compressive strength and water absorption in a wide range of chemical composition and temperature treatment data, and the highest average regression coefficient (r2) of 0.993 for compressive strength was obtained, while r2 for water absorption was 0.996. Obtained ANN model performs better when compared to developed empirical non-linear multivariable regression model. The wide range of processing variables were considered for the formulation of this model, and its easy implementation in a spreadsheet using a set of equations, makes it very useful and practical for compressive strength and water absorption prediction. 62 Institut za ispitivanje materijala a.d. Beograd
Z. Odanović, M. Đurđević, V. Grabulov, M. Arsić
EFFECTS OF STEELMAKING PROCESS AND HEAT TREATMENT PROCEDURES ON THE ULTRA HIGH STRENGH STEEL PROPERTIES 22nd Congress of Chemists and Technologists of Macedonia with international participation, 2012, Ohrid, Macedonia, M-7. An investigation of the effects of the steelmaking process on the tensile and fracture toughness properties of the ultra high strength steel (UHSS) is presented in this work. Three different steelmaking technologies were performed for production an UHSS - Maraging steel with 18% Ni. Air induction melting followed by electron beam (EB) remelting, vacuum induction melting followed by EB remelting and vacuum induction melting followed by electric slag remelting (ESR) were alied for steel production. Obtained steel ingots were forged to bars and were heat treated according the standard procedure for maraging steel as quenching followed with aging. The influence of steelmaking procedures on basic mechanical properties and fracture toughness (KIc) as well as dynamic fracture toughness (KId) is assessed. Steels produced by all three steelmaking procedures show a good combination of high tensile properties and fracture toughness. Vacuum induction melting followed by ESR showed better operational features than the other two steelmaking procedures. Keywords: UHSS, maraging steels, steel production, steel properties.
A. Terzić, Lj. Miličić, Z. Radojević, M. Arsenović, Lj. Pavlović, Z. Aćimović- Pavlović
POSSIBILTIES OF USING FLY ASH AS COMPONENT IN COMPOSITES REGARDING TOXIC ELEMENTS LEACHING PREVENTION 22nd Congress of Chemists and Technologists of Macedonia with international participation, 2012, Ohrid, Macedonia, 170. Fly ash, which is the residue from coal combustion in plants-operating-at-high- temperature, is severe hazard for the environment. The disposal of the fly ash may pose a significant risk to the environment due to the possible leaching of hazardous pollutants, such as toxic metals. The only economic and sustainable Pregled naučnih i stručnih rezultata u 2012. godini 63 solution for the pollution-prevention of the air, water and soil is the realication of fly ash as one of the components in construction material composites. There is a risk of leaching even when fly ash is built-in the construction composites and the goal of this investigation was to prove that leaching concentrations of number of toxic elements is in range assigned by actual regulations. Fly ashes from various landfills, afterwards storage in closed silos, were alied in several composite samples (mortar, concrete and brick) without any physical or thermal pre-treatment. Testing composites were based on fly ash mixed with binder or with binder and aggregate. The leachability of the potentially toxic elements from the fly ash based products was investigated. The leaching behavior and potential environmental impact of the 11 potentially hazardous elements was tracked: Pb, Cd, Zn, Cu, Ni, Cr, Hg, As, Ba, Sb and Se. A detailed study of physico-chemical characteristics of the fly ash, with accent on trace elements and the chemical composition investigation is included. Investigation of mineralogical constituents of the fly ash is emphasized, due to the fly ash dependence of its origin. Thermal stability of crystalline phases was investigated with DTA. The microstructure of the fly ash and fly ash based composites was studied by means of SEM analysis. The overall results showed that most of the elements are more easily leachable from the fly ash in comparison with the fly ash based composites. The leaching of investigated toxic elements is within allowed range thus investigated fly ashes can be reused in construction materials production. Keywords: leaching, toxic elements fly ash, realication, construction composites.
A. Mitrovic, M. Zdujić
ACTIVATION OF POZZOLANIC ACTIVITY OF KAOLINITE CLAY: THERMAL AND MECHANOCHEMICAL TREATMENT 22nd Congress of Chemists and Technologists of Macedonia with international participation, 2012, Ohrid, Macedonia, I-21, 238. This paper compares the pozzolanic activity of metakaolin obtained by thermal treatment and amorphous kaolin obtained by mechanochemical treatment. Optimal thermal treatment parameters are temperature 650 °C and heating time 120 min during which pozzolanic activity of 0.45 gCa(OH)2/g Pozz is obtained. To increase activity metakaolin was milled 5 min after which pozzolanic 64 Institut za ispitivanje materijala a.d. Beograd activity rose to 0.70. Mechanochemical treatment was performed in a Herzog oscillating mill for 15–120 min. The highest pozzolanic activity of 0.74 was obtained by milling clay for 2 h. The starting material used is Serbian kaolinite clay „Miličnica“ which is by means of kaolinite content and loss of ignitation medium-quality raw material. Beside kaolinite, the other main mineral constituent is quarz. According to Aparicio-Gala’n-Ferrell - AGFI s method the clay is medium degree of orderness. The results indicate that both processes might be alied for obtaining reactive pozzolana from investigated kaolinite clay. It is evident that alied mechanochemical treatment results in higher value for pozzolanic activity, comparable with those obtained for commercial metakaolin. Use of the mechanochemical treatment has additional benefits, alied technology is favourable in the view of environmental protection, and throught the lower production cost. Keywords: metakaolin, amorphous kaolin, calcination, mechanochemical treatment, pozzolanic activity. Pregled naučnih i stručnih rezultata u 2012. godini 65
4. ČASOPISI NACIONALNOG ZNAČAJA (M50)
RAD U ČASOPISU NACIONALNOG ZNAČAJA (M51)
A. Terzić, Lj. Pavlović, Lj. Miličić, Z. Radojević, Z. Aćimović Pavlović
PROPERTIES OF REFRACTORY BONDING AGENT BASED ON WASTE MATERIAL Građevinski materijali i konstrukcije, 2012, No. 2. vol. 55, 47-57. The fly ash disposal on open landfills poses significant risk to the environment. Sustainable solution for the pollution-prevention is reuse of fly ash in building materials. Building composites – high temperature bonding agents, in which fly ash is combined with refractory components is new option for realication of this waste material. In this study, investigated bonding agent was based on fly ash mixed with high-aluminate cement. Fly ash previously underwent mechanical activation. Mineral phase analysis of the composite by means of XRD was accented due to the changes occurring with increasing temperature. Processes taking place during composite thermal treatment from 20 up to 1100 ºC were identified by means of DTA method. The leaching behavior and potential environmental impact of hazardous elements were analyzed. Investigated fly ash-cement composite proved to have high physico-mechanical performances, but also good thermo-insulation characteristics. The overall results showed that alication of the fly ash in high-temperature bonding agents is sustainable solution for managing this environmentally hazardous waste material. Keywords: building composites fly ash, thermo-insulation, toxic elements, realication, building composites. 66 Institut za ispitivanje materijala a.d. Beograd
W. Schütt, М. Drpić
NEW REGULATIONS FOR THE BUILDING SECTOR COOPERATION BETWEEN MINISTRY OF ENVIRONMENT AND SPATIAL PLANNING, SERBIAN SECTOR EXPERTS, SERBIAN SECTOR ASSOCIATION AND INSTITUTIONS OF THE EU- COUNTRIES Technics, special edition, LXVII 2012, 124 – 128. Energy efficiency in household and buildings leads to most important energy savings. In order to promote energy-efficient buildings, and declaration of energy efficiency and alication of minimum requirements to energy performance of buildings, in Serbian laws and regulatory documents will see more changes, which leads to new laws and proposals (rules) as well as new global aroach into field of reduction of energy consumption. Each project in this way shall be essentially suorted by EPBD-requirements. This Directive with set of standards must be a basis. But the technical work has to be suorted by new ways of cooperation between the public and private sector. Organization of problem solving was vary important. In this Project, the main objective was to define necessary energy efficiency measures on the level of a building, in all phases of urban planning (where alicable) and architectural designing process. This includes: determination of technical conditions for the design of urban systems; determination of technical conditions for the design of buildings; determination of recommendations to be included in other building regulations which would be affected by the need of implementation of energy efficiency in the building practice; determination of glossary of terms regarding energy efficiency in the field of architecture and urban planning; definition of methodology for energy consumption calculation; definition of methodology to arrive to planned levels. The used methodology includes identification of relevant EU standards (i.e.: EN standards), directives and other regulatory documents which should set criteria that should be posed and achieved in the future EE regulations in Serbia, as well as a thorough research of present Serbian building regulations and norms and pointing out parts that should be changed or adjusted according to the future Serbian energy efficiency regulations. The main technical suort was made through study tours to institutions and industrial companies in Germany, workshops and presentations. Pregled naučnih i stručnih rezultata u 2012. godini 67
The first three Proposals (i.e.: Rules) - drafts are: Rule on energy efficiency of buildings; Rule on certification of buildings; Rule on certification of subjects, which participate in certifications processes. The first draft – recast of our standard SRPS U.J5.600, Part 1- Thermal technique and energy efficiency in buildings – Technical conditions for the design and construction of buildings, is prepared for Serbian Institute for Standardization (ISS – Belgrade). The final planned deadline for all works in this Project-Phase is stated with the end of 2010. Keywords: energy-efficient building; energy performance; minimum requirements; EPBD-Directive; law; global aroach; energy consumption; organization of problem solving; rule; standard.
D. Bojović, D. Nikolić, K. Janković, Lj. Lončar
EVAULATION OF AIR CONTENT ON CONCRETE COMPRESSIVE STRENGTH WITH CLASSICAL AROACH AND NEURAL NETWORKS Građevinski materijali i konstrukcije, 2012, vol. LV, No. 1, 47-54. Many parameters influence on the characteristics of fresh and hardened concrete. One of the most important characteristic of concrete is its porosity. Measure the porosity of fresh concrete is measured by the amount of entrained air. The effect of entrained air in concrete on compressive strength investigated by many authors. On the bases these works we have two formulas alicable in practice. Soft programming techniques especialy neural networks and the formation of databases related to the testing in laboratories for concrete opened up new aroaches in predicting the impact of the quantity of entrained air in concrete on compressive strength.
S. Dević, M. Cocić
MIKROSKOPSKI PRIKAZ EROZIJE MAGHROMOTNE VATROSTALNE OPEKE LIVNOG LONCA USLED DEJSTVA TROSKE Zaštita materijala, God. 3, br. 3. (2012), 221-225. 68 Institut za ispitivanje materijala a.d. Beograd
Problematika koja je tretirana u ovom radu odnosi se na objašnjenje i prikaz erozije maghromitnih vatrostalnih opeka livnog lonca za čelik. Erozija maghromitnih vatrostalnih opeka nastala usled dejstva troske ispitana je primenom mikroskopske metode. Mikro snimci su rezultat mikroskopskog ispitivanja maghromitnih vatrostalnih opeka u propuštenom svetlu. Oni jasno prikazuju eroziju vatrostalne opeke. Na mikro snimcima se vidi postepen prodor troske u vatrostalnu opeku, njeno destruktivno dejstvo i na kraju rušenje strukture vatrostalne opeke.
A. Mitrović, D. Nikolić
PROPERTIES OF PORTLAND-COMPOSITE CEMENTS WITH METAKAOLIN: COMMERCIAL AND MANUFACTURED BY THERMAL, ACTIVATION OF SERBIAN KAOLIN CLAY MATEC Web of Conferences 2, 01002 (2012) http://www.matec-conferences.org/ Portland-composite cements (CEM II) were prepared with addition of 5 to 35% of metakaolin (MK), manufactured by thermal activation/calcination of Serbian kaolin clay, and commercial matakaolin (CMK). Performance of the composite cements was evaluated, through the setting time (initial and final), compressive strengths (for ages 2, 7, 28, 90 and 180 days) and soundness, and compared with control cement (Portland cement – CEM I). Setting time (initial and final) is accelerated in Portland-composite cements, for both metakaolins used. The acceleration is higher in cement with addition of commercial metakaolin. Lower compressive strength is obtained after 2 days of curing for all Portland- composite cements in comparison with control cement, since pozzolanic reaction still did not show its effect. After 7 days, pozzolanic reaction show its effect, manifested as compressive strength increase of Portland-composite cements with addition of up to 35% of CMK, and 25% in the case of cements with MK. After 28 days compressive strength was higher than that for control cement for cements prepared with addition of CMK, and with addition of up to 25% MK. Pregled naučnih i stručnih rezultata u 2012. godini 69
After 90 days increased compressive strength was noticed with addition of 10 - 20% of CMK, and with 10 and 15% of MK, while after 180 days addition of both metakaolins influences compressive strength decrease. The results of the soundness, 0.5 mm for CEM I, and 1.0 mm in most Portland- composite cements indicate soundness increase with addition of metakaolins. Generally, better performance of Portland-composite cements was obtained with addition of commercial metakaolin, which may be attributed to the differences in the pozzolanic activity of the alied metakaolins, 20.5 MPa and 14.9 MPa for CMK and MK, respectively. By our previous findings pozzolanic activity of the thermally activated clay may be increased by subsequent milling of the metakaolin manufactured by thermal activation process. Keywords: Portland-composite cements, metakaolin, setting time, compressive strength, soundness. 70 Institut za ispitivanje materijala a.d. Beograd
RAD U ČASOPISU NACIONALNOG ZNAČAJA (M52)
A. Terzić, Lj. Pavlović, Z. Radojević, Lj. Miličić, Z. Aćimović-Pavlović
BUILDING MATERIALS BASED ON FLY ASH AS POSSIBLE SOLUTION FOR REDUCTION OF AIR POLLUTION CAUSED BY EMISSIONS FROM POWER-PLANTS Tehnika, 2012, No. 2, 311-317. Most frequent environmental pollution sources are emissions caused by technological processes taking place at power-plants. High production of fly ash, the main residue in coal combustion, represents extreme hazard for the environment. Air pollution is taking proportions that require special attention, thus certain regulations are being imposed. The goal of the legislation is to reduce harmful emissions into the atmosphere by imposing standards for air quality and maximum emissions from various sources. Besides regulations, option of realication of fly ash in building materials industry is another solution for on-going problem. Fly ash can be used as component in cement, mortar, concrete, bricks, tiles, asphalt. Using produced fly ash capacities is sustainable solution for saving natural resources and environmental protection, but also a basis for designing new building materials from recycled nusproducts. Keywords: fly ash, pollution, regulations, building materials.
J. Ćirilović, N. Vajdić, G. Mladenović, C. Queiroz
PROCENA TROŠKOVA REHABILITACIJE I REKONSTRUKCIJE U SISTEMIMA ZA UPRAVLJANJE ODRŽAVANJEM PUTEVA Put i saobraćaj, 2012, II, 5-13. Prosečni jedinični troškovi radova u projektima rekonstrukcije i rehabilitacije (RiR) puteva se značajno razlikuju među državama, ali i u okviru različitih projekata u istoj državi, i to usled mnogobrojnih faktora. U okviru ovog rada, formiran je model kojim bi bilo moguće predvideti troškove radova RiR u različitim državama i koji bi mogao da se primeni u analizama u sistemima za upravljnje održavanjem puteva na strateškom nivou i na nivou programiranja Pregled naučnih i stručnih rezultata u 2012. godini 71 radova održavanja. Definisan model je formiran od promenljivih koje značajno doprinose regresiji. Izabrane su one promenljive kojima je moguće što bolje opisati zavisnu veličinu tj. jedinične troškove RiR puteva. Dobijena regresiona zavisnost bi mogla da bude korisna na nivou strateških analiza mreža i optimizacija planiranih radova RiR. Ključne reči: procena troškova, rehabilitacija i rekonstrukcije puteva, sistemi za upravljanje održavanjem, složena regresiona analiza. 72 Institut za ispitivanje materijala a.d. Beograd
RAD U NAUČNOM ČASOPISU (M53)
M. Arsić, S. Bošnjak, Z. Odanović, M. Mladenović, N. Milovanović
STATE ANALYSIS OF THE UER RING OF THE TURBINE RUNNER GUIDE VANE AARATUS OF HYDROELECTRIC GENERATING SET A6 ON HYDRO POWER PLANT DJERDAP 1 Energija, ekonomija, ekologija, Vol. 14, br. 1-2, 2012, 197-202. During the refurbishment of the hydroelectric generating set A6 on H „Djerdap 1”, for the state analysis and assessment of the level and causes of degradation of the structure of the vertical Kaplan turbine runner guide vane aaratus non- destructive tests and inspections, as well as destructive tests of base material and welded joints, have been carried out. Results of non-destructive tests performed on welded joints are presented in this paper (magnetic particle and ultrasonic inspection), as well as results of destructive tests of the base material and welded joints (testing of tensile properties, impact testing, metallographic analyses of the structure). A large number of crack type line indications were detected by magnetic particle inspections, while the occurrence of partial penetration in roots of welded joints was detected by ultrasonic inspections, as well as lamellar tearing of the base material. Tensile properties of tested samples taken in longitudinal and transverse direction fulfilled the requirements of the standard with certain deviations, which does not stand for samples taken in z-direction with significantly lower values of contraction of the cross-section than minimum prescribed values, which proves that base material is not resistant to the occurrence of lamellar cracks. Metallographic tests performed on specimens taken from the base material in longitudinal and transverse direction showed that the microstructure is stripe-shaped and ferrite-pearlite with non- metallic inclusions of oxide, sulphide, silicate and aluminate type, while metallographic tests performed on specimens taken from welded joints showed that their microstructure is stripe-shaped and ferrite-pearlite with non-metallic inclusions of oxide type. On the basis of results of experimental tests the analysis of the causes of occurrence of lamellar tearing of the base material and crack type defects in welded joints has been carried out. Keywords: hydro turbine, welded structure, degradation of material, crack. Pregled naučnih i stručnih rezultata u 2012. godini 73
M. Arsić, B. Vistać, Z. Savić, Ž. Šarkočević, Z. Anđelković
DAMAGE CAUSE ANALYSIS AND REPARATION OF THE SYNCHRONOUS VALVE CASING OF HYDROELECTRIC GENERATING SET A1 ON HYDRO POWER PLANT PIROT Energija, ekonomija, ekologija, Vol. 14, br. 1-2, 2012, 227-232. Corrosion, erosion and cavitation have a significant influence on parts of turbine and hydromechanical equipment in exploitation. The same can be said when it comes to damaging of surfaces of the synchronous valve which is a part of the vertical Francis turbine runner of the hydroelectric generating set A1 at H ’’Pirot’’, with nominal power of 40 MW. Casing of the synchronous valve has been made of structural steel 422.712.5, while stiffening ribs have been made of Cr-Ni steel 17246. Both types of steel have been produced in Czech Republic. Conical valve seat has been surface welded with bronze. Effect of corrosion on structural steel in high humidity conditions, because of the presence of freshwater, causes damaging of metal due to the occurrence of initial cracks and their propagation, which can lead to failure due to the effect of variable loads in a short period of time. Presence of solid particles in the fluid, which occurs due to corrosion and wearing of components, causes the surface erosion. Rate of metal erosion depends on a large number of influential factors: dimensions of particles, particle velocities, particle concentration, physical and mechanical properties of particles, material that wears out etc. The most dangerous mechanism of liquid erosion is cavitation, which comprises formation and implosion of bubbles within the fluid. Cavitation causes the formation of cavities, or in other words space hollowed out on the surface of metal. Process of removal of material from the surface is called cavitation erosion, and the resulting damage is cavitation damage. Erosion of surfaces of hydraulic machine components exposed to the effect of cavitation can become a large scale problem in a short while, while depths of cavities can reach up to 100 mm. The methodological aroach to determination of the state of damaged components of turbine and hydromechanical equipment on hydro power plants (runner, synchronous valve, pre-turbine disc shutter, ...) is presented in this paper through the example of the synchronous valve of the hydroelectric generating set A1 at H ’’Pirot’’. Keywords: synchronous valve, damage, reparation, surface welding. 74 Institut za ispitivanje materijala a.d. Beograd
M. Arsić, B. Vistać, Z. Odanović, A. Đorđević, Z. Savić
REPAIR WELDING METHODOLOGY FOR THE TURBINE SHAFT AT THE HYDROELECTRIC POWER PLANT “DJERDAP 2 WITHOUT DISASSEMBLING THE HIDROELECTRIC GENERATING SET Research & Development (Istraživanje i razvoj), 2012, Vol. 18, No. 3, 73-80. Horizontal Kaplan turbines, made in Russia, were installed in 10 hydroelectric generating units at „DJERDAP 2“. Nominal power of each is 28 MW. After 163.411 hours (aroximately 22 years) of operation, the fracture of the hydro- electric generating set A6 turbine shaft in the area of high stress concentration occurred, at the transition radius R80 between the flange and the runner hub. That occurrence caused the use of non-destructive testing methods (visual inspection, dye-penetrant testing, magnetic particle testing, ultrasonic testing) in order to determine the state of welded joints and base material of all other turbine shafts. It was established that there is a large number of surface cracks at all shafts along the circumference, in the transition radius area, which could be repaired through the use of the repair welding technology, although the individual cracks were 430 mm long and 20 mm deep. Hollow turbine shafts have been assembled by welding together 3 separate parts. Cylindrical parts were made of steel 20GS, while the flange area of the shaft and flange itself were made of steel 20GSL In order to extend the service life and save the time regarding the disassembling and assembling of the turbine shaft, the repair welding methodology without disassembling the hydroelectric generating set has been developed. Repair welding methodology for turbine shafts, due to their structural solution and function in exploitation, has to embrace a large number of details, carefully consider them and, as well, ensure that their execution is performed with high precision. If any of these details would be overlooked, underestimated or incorrectly perceived, significant problems in turbine operation could arise. This paper, due to specificity of the methodology used for shaft repairing, apart from the welding technology also presents the procedure for shaft preparation with the order of operations. Keywords: Turbine shafts, tests, crack, repair welding methodology. Pregled naučnih i stručnih rezultata u 2012. godini 75
5. ZBORNICI SKUPOVA NACIONALNOG ZNAČAJA (M60)
PREDAVANJE PO POZIVU NA SKUPU NACIONALNOG ZNAČAJA ŠTAMPANO U CELINI (M61)
D. Nikolić
OPTIMIZACIJA GREDNIH NOSAČA OD BETONA ULTRA VISOKIH ČVRSTOĆA PRIMENOM GENETSKIH ALGORITAMA Savremena građevinska praksa, Andrevlje, Fakultet tehničkih nauka Novi Sad, 2012, 235-251. Beton ultra visokih čvrstoća (UHPC) poseduje izuzetno visoka mehanička svojstva i u poređenju sa konvencijalnim betonima predstavlja superioran materijal kako u pogledu mehaničkih svojstava, tako i u pogledu trajnosti. Da bi se moglo predvideti ponašanje grednih nosača od UHPC, prvo su izvršena eksperimentalna istraživanja mehaničkih svojstava samog kompozita sa 2% i 4% zapreminskog udela čeličnih vlakana. Nakon toga, četiri gredna nosača dužine 2m su ispitana na savijanje do loma sa opterećenjem u trećinama raspona. Dve grede su bile amirane samo mikro čeličnim vlaknima, dok su dve grede sadržale i klasičnu armaturu. Na osnovu eksperimentalnih ispitivanja i predloženih preporuka AFGC za UHPC, modelovano je ponašanje grednih nosača i izvršena je optimizacija primenom genetskih algoritama (GA) prema kritrijumu minimalne cene. U radu je takođe ukazano na odnos jedinične cene grednih nosača od UHPC mikroarmiranih čeličnim vlaknima u odnosu na grede koje sadrže i klasičnu ili prednapregnutu armaturu. 76 Institut za ispitivanje materijala a.d. Beograd
SAOPŠTENJE SA SKUPA NACIONALNOG ZNAČAJA ŠTAMPANO U CELINI (M63)
O. Vušović, I. Delić-Nikolić, B. Ivović
MINERALOŠKO-PETROLOŠKI SASTAV I TEHNIČKE KARAKTERISTIKE STENSKE MASE SA LEŽIŠTA ČOKONJAR 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012, 2165-2173. Mnoga svojstva stene su povezana sa njenim mineralnim sastavom. Takođe tekstura, struktura i vrsta cementa ili matriksa koji povezuje zrna utiču na njene fizičko-mehaničke karakteristike. Ključne reči: minerali, struktura, tekstura, matriks.
I. Delić-Nikolić, B. Ivović, O. Vušović
ODREĐIVANJE POLIRANJA KAMENOG AGREGATA (PSV) 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012, 67-73. Poliranje kamenog agregata je karakteristika koja određuje stepen otpornosti krupnog kamenog agregata prema polirajućem dejstvu automobilskih guma u uslovima sličnim onima koji se javljaju na površini puta. Uticaj automobilskih guma na površinu puta ogleda se u uglačavanju habajuće površine, stepen uglačanosti, odnosno ispoliranosti je jedan od glavnih faktora koji utiču na otpornost prema klizanju. Ključne reči: poliranje kamenog agregata, agregati za asfaltne mešavine. Pregled naučnih i stručnih rezultata u 2012. godini 77
M. Drpić, D. Ivanišević
ZAŠTITA OD POŽARA ZIDANIH KONSTRUKCIJA U SKLADU SA TEHNIČKOM REGULATIVOM U SRBIJI I U EVROPI Zidane konstrukcije zgrada i tehnička regulativa, Građevinski fakultet Univerziteta u Beogradu, 2012, 183–191. Zaštita od požara zidanih konstrukcija u skladu sa tehničkom regulativom u Srbiji propisana je u okviru nekoliko pravilnika i SRPS standarda. U međuvremenu, preuzet je veliki broj EN standarda – kao SRPS EN. Evrokodovi, u formi SRPS EN standarda, se preuzimaju. Uz njih treba da budu izrađeni odgovarajući nacionalni prilozi. Ključne reči: zaštita od požara; zidana konstrukcija.
M. Drpić, D. Ivanišević
MATERIJALI KOJI SE PRIMENJUJU U OBLASTI ZIDANIH KONSTRUKCIJA ZGRADA I NJIHOV UTICAJ NA TOPLOTNU IZOLACIJU Zidane konstrukcije zgrada i tehnička regulativa, Građevinski fakultet Univerziteta u Beogradu, 2012, 87–100. Toplotna izolacija materijala koji se primenjuju u oblasti zidanih konstrukcija zgrada u svojim osnovnim parametrima određena je postojećom tabelom standarda SRPS U.J5.600, koja je uvršćena i u (novi) Pravilnik o energetskoj efikasnosti zgrada. Pravilnik se poziva i na neke od SRPS EN standarda, kojima se takođe propisuju osnovni parametri – toplotna (i parodifuzijska) svojstva materijala i proizvoda za zidanje. Često postoji potreba za izradom Nacionalnih priloga uz odgovarajući SRPS EN standard. Pravci za neophodna usaglašavanja su: inoviranje – posebno za nove materijale; uspostavljanje kontrola proizvodnje i/ili uvoza; akvizicija podataka – stvaranje baze podataka materijala za (novi) softverski paket, oslonjen na Pravilnik. Nacionalni prilozi SRPS EN standarda treba da budu izrađeni na bazi prethodno usvojene metodologije i po principu neselektivnosti. Parametri treba da budu odobreni u skladu sa opštim – propisanim nivoom pouzdanosti. Ključne reči: materijali; zidana konstrukcija; zgrada; toplotna izolacija. 78 Institut za ispitivanje materijala a.d. Beograd
M. Drpić, D. Ivanišević
TOPLOTNA SVOJSTVA ELEMENATA ZA ZIDANJE OD PEČENE GLINE Primena proizvoda od gline u izgradnji energetski efikasnih zgrada, Beograd, 2012, 47–58. U radu se razmatraju toplotna svojstva glinenih zidarskih proizvoda u termičkom omotaču zgrade. Daju se pravila za određivanje toplotne provodljivosti i/ili toplotne otpornosti. Određeni građevinski proizvod može da ima različite projektne toplotne vrednosti, saglasno planiranoj primeni. Pokriveni su: puni elementi za zidanje, elementi za zidanje koji sadrže oblikovane šupljine i kompozitni elementi za zidanje. Ključne reči: toplotna svojstva, glineni proizvod, termički omotač, zgrada, toplotna provodljivost, toplotna otpornost, projektna vrednost, zidana konstrukcija, zidarski proizvod, planirana primena.
D. Berisavljević, N. Šušić
OSNOVE ISPITIVANJA INTEGRITETA ŠIPOVA S PRIMERIMA IZ PRAKSE - BASIS OF PILE INTEGRITY TESTING WITH FEW CASE HISTORIES Građevinski materijali i konstrukcije, br. 1, Društvo za ispitivanje i istraživanje materijala i konstrukcija Srbije, Beograd, 2012, 55-64. U poslednjih nekoliko godina, ispitivanje integriteta ugrađenih šipova postalo je veoma popularno na gradilištima u našoj zemlji. Pri tom, posebno mesto zauzima zvučna metoda, „Sonic Integrity Test“ kao pouzdana, jeftina i vremenski malo zahtevna, a namenjena ispitivanju kvaliteta izvedenih šipova. U radu su prikazane osnove metode, teorijske postavke i nekoliko primera iz naše prakse. Ključne reči: SIT, integritet, šip, signal. Pregled naučnih i stručnih rezultata u 2012. godini 79
N. Šušić, D. Berisavljević
DINAMIČKO ISPITIVANJE ŠIPOVA Simpozijum Društva građevinskih konstruktera Srbije, Vrnjačka Banja, 2012, 309-314. U radu su opisane dve metode dinamičkog ispitivanja šipova, sonic integrity testing (SIT) i Dynamic load testing (DLT). Osnovni zadatak DLT metode je određivanje nosivosti šipa, zadatak SIT metode je da se odredi integritet šipa. Ključne reči: SIT, DLT, integritet, nosivost.
M. Ćosić, Z. Aćimović-Pavlović, A. Terzić, B. Nedeljković, Lj. Pavlović
PRIMENA RHEOCASTING PROCESA ZA DOBIJANJE KLIPNIH LEGURA POBOLJŠANIH SVOJSTAVA IX Naučno–stručni simpozijum sa međunarodnim učešćem Metalni i nemetalni materijali - proizvodnja – osobine – primjena, Zenica, BiH, 2012, 53-59. U radu su prezentirani rezultati ispitivanja promene strukture nadeutektičke Al18%Si legure dobijene klasičnim postupkom livenja, kao i primenom mehaničkog postupka mešanja u poluočvrslom stanju - reokasting postupak. Korišćen je mehanički postupak mešanja pločastim mešačem pri različitoj brzini obrtanja aktivnog dela od 500; 1000 i 1500 o/min. Ispitivan je uticaj efekata mehaničkog mešanja na strukturu legure u oblasti polučvrstog stanja. Analiziran je uticaj brzine mešanja u intervalu od 500-1500 o/min na raspodelu -Al čvrstog rastvora i čestica primarnog Si. Zapaženo je da primenom brzine mešanja 1500 o/min dolazi do najbolje raspodele faza što utiče na -Al čvrstog rastvora primenom mešanja u poluočvrslom stanju su promenile morfologiju od dendritne u nedendritnu. Rezultati istraživanja su pokazali da nova metoda livenja - reokasting proces omogućava promenu strukture i svojstava klipnih legura što će uticati na poboljšanje kvaliteta ove vrste odlivaka. Ključne reči: reokasting proces, brzina mešanja, kvalitet odlivaka. 80 Institut za ispitivanje materijala a.d. Beograd
T. Spasojević-Šantić, G. Dražić, Z. Radojević
BIOREMEDIJACIJA ZEMLJIŠTA ZAGAĐENOG TEŠKIM METALIMA, 7. SIMPOZIJUM “RECIKLAŽNE TEHNOLOGIJE I ODRŽIVI RAZVOJ 7. Simpozijum „Reciklažne tehnologije i održivi razvoj“, 7. SRTOR, Soko Banja, 2012, 472-477. Usled naglog industrijskog razvoja i povećane poljoprivredne proizvodnje dolazi do kontaminacije zemljišta teškim metalima kao što su kadmijum, živa, nikl, olovo i dr. Brojna istraživanja ukazuju na njihovu toksičnost, ponašanje u zemljištu i ulaženje u lanac ishrane preko biljaka. Sve to utiče na smanjenje funkcije zemljišta i onemogućavanja sposobnosti samoprečišćavanja životne sredine. Bioremedijacija se može definisati kao biološki proces u kome se koriste mikroorganizmi ili njihovi enzimi za vraćanje narušene životne sredine u originalno stanje. Mikroorganizmi mogu različitim mehanizmimima vršiti dekontaminaciju zemljišta i voda zagađenih teškim metalima. Cilj ovog rada je da se ukaže na potrebu bioremedijacije zemljišta zagađenih teškim metalima kako bi se izvršila revitalizacija degradiranih područja i povećala stabilnost ekosistema. Ključne reči: bioremedijacija, teški metali, degradirana područja.
D. Perović, T. Spasojević-Šantić
UTICAJ ISTROŠENIH BATERIJA NA ŽIVOTNU SREDINU I ZDRAVLJE LJUDI 7. Simpozijum „Reciklažne tehnologije i održivi razvoj“, 7. SRTOR, Soko Banja, 2012, 206-211. Nelegalnom dekompozicijom istrošenih baterija na komunalnim deponijama dolazi do kontinuirane kontaminacije lokaliteta u dužem vremenskom periodu. Teški metali i ostale toksične materije iz istrošenih baterija dospevaju u životnu sredinu (podzemne i površinske vode, zemljište, biljke, životinje) a samim tim i u ljudski organizam. Istrošene baterije se smatraju izvorom sekudarnih sirovina jer sadrže metale koji mogu biti reciklirani, odnosno izdvajanjem ovih metala koji se ponovo koriste čuvaju se prirodni resursi i smanjuje se zagađenje životne sredine. Republika Srbija nema postrojenje za reciklažu baterija, ali se započelo Pregled naučnih i stručnih rezultata u 2012. godini 81 sa njihovim prikupljanjem i privremenim skladištenjem radi slanja na dalji tretman u ovlašćena postrojenja u zemlje EU. Stoga je u ovom radu posebno naglašena potreba za uspostavljanjem organizovanog sistema upravljanja istrošenim baterijama kako bi se smanjio negativan uticaj na životnu sredinu i povećao procenat recikliranja. Ključne reči: baterije, teški metali, životna sredina, zdravlje.
Z. Radojević, M. Vasić
PROIZVODI OD GLINE – ASORTIMAN, KVALITET I TEHNIČKA REGULATIVA Primena proizvoda od gline u izgradnji energetski efikasnih zgrada, Beograd Srbija, 2012. U ovom radu su razmatrani proizvodi od gline koji se izrađuju u Srbiji. Predstavljeni su asortimani iz dve osnovne grupe proizvoda od gline: proizvodi za preklopno pokrivanje krovova (crepovi) i elementi za zidanje od gline (opeke i blokovi). Dat je prikaz sadašnjeg stanja i u naznakama budućeg razvoja industrije glinenih proizvoda u Srbiji saglasno zahtevima koje postavlja energetski efikasna gradnja i osnovni zahtevi održivog razvoja. Analiziran je kvalitet proizvoda iz različitih pogona a ispitivanja su izvršena u skladu sa zahtevima SRPS i EN standarda. Prikazane su karakteristike opekarskih blokova značajne za ocenu toplotnih performansi zidova u koje se ugrađuju. U radu je obrađena i tehnička regulativa vezana za ovu grupu proizvoda. Ključne reči: crepovi, blokovi od gline, kvalitet, tehnička regulativa.
M. Vasić, Z. Radojević
UTICAJ BRZINE, TEMPERATURE I VLAŽNOSTI VAZDUHA NA PROCES KONVEKTIVNOG SUŠENJA OPEKA 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012, 405-412. U radu je ispitivan uticaj brzine, temperature i vlažnosti vazduha za sušenje na proces konvektivnog sušenja opekarskih proizvoda sa ciljem izračunavanja koeficijenata prenosa toplote i efektivnog difuzionog koeficijenta. 82 Institut za ispitivanje materijala a.d. Beograd
Eksperimentalna istraživanja su izvršena na uzorcima pločica od gline (120x50x14mm) u laboratorijskoj recirkulacionoj sušnici za unapred definisane vrednosti temperature (40-70 0C), vlažnosti (40-80 %) i brzine (1-3 m/s) vazduha za sušenje. Temperature površine proizvoda kao i temperature, vlažnosti i brzine vazduha za sušenje su registrovane u pravilnim vremenskim intervalima (1-5 min.). Na bazi eksperimentalnih istraživanja uspostavljene su zavisnosti kritične vlažnosti i efektivnog difuzionog koeficijenta u funkciji temperature, vlažnosti i brzine vazduha za sušenje. Ključne reči: Sušenje, opekarski proizvodi.
M. Vasić, M. Arsenović, Z. Radojević
USPOSTAVLJANJE REŽIMA BRZOG SUŠENJA U LABORATORIJSKIM USLOVIMA 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012, 397-403. U radu je u kratkim crtama dat prikaz opsežnog istraživanja procesa sušenja nekoliko opekarskih sirovina sprovedenih u laboratorijskoj recirkulacionoj sušnici. Na osnovu prikupljenih podataka projektovan je i uspešno uspostavljen optimalni režim brzog sušenja opekarskih proizvoda. Opekarske sirovine okarakterisane kao slabo osetljive na sušenje se ne mogu koristiti u ovom procesu, dok su one okarakterisane kao jako osetljive adekvatne za upotrebu pri brzom sušenju. Ključne reči: Brzo sušenje, opekarski proizvodi, osetljivost na sušenje.
M. Vasić, Z. Radojević
USPOSTAVLJANJE OPTIMALNOG REŽIMA SUŠENJA U INDUSTRIJSKIM USLOVIMA 4th International Conference Civil Engineering – Science and Practice, Žabljak, Crna Gora, 2012, 413-420. U radu je u kratkim crtama na primeru šupljeg bloka sa horizontalnim šupljinama dimenzija 190x250x190mm, dat prikaz istraživanja optimalnog procesa sušenja u industrijskim uslovima. Istraživanja su sprovedena u Pregled naučnih i stručnih rezultata u 2012. godini 83 komornim sušnicama tipa „Caeleti“ jednog renomiranog domaćeg proizvođača opeke. Za prikupljanje eksperimentalnih podataka korišćeni su rezultati merenja određenih parametara procesa sušenja koji su očitani pomoću fiksnih / ugrađenih mernih sondi koje pripadaju sušnici i pokretnog CeryDry „Data loggera“ koji služi za kontinualno registrovanje: Temperature, relativne vlažnosti i linearnog skupljanja proizvoda. Na osnovu prikupljenih podataka projektovan je i uspostavljen optimalni režim sušenja opekarskih proizvoda. Ključne reči: Sušenje, opekarski proizvodi, komorna sušnica.
G. Ćirović, S. Mitrović, K. Janković, D. Nikolić
OPTIMIZACIJA FRP/AB GREDA PRIMENOM KUKU PRETRAGE XXXIX SYMOPIS, Visoka građevinsko-geodetska škola, Tara, 2012, 159-162. U radu je prikazana primena „Kuku“ pretrage (Cuckoo Search-CS), nove metaheurističke metode optimizacije sa jedinstvenim karakteristikama i u kombinaciji sa Levy-jevom raspodelom verovatnoće(Levy flights). Razmatran je problem optimalnog dimenzionisanja i ojačanja grednog nosača sa FRP materijalima opterećenog na savijanje. Analizirana je inicijalna jedinična cena grednog nosača za različite vrednosti momenta savijanja, a potom i cena primene FRP materijala pri povećanju eksploatacione odnosno granične nosivosti za 15%. Ojačanje grede za 15% povećanja opterećenja povećava jediničnu cenu utroška materijala čak i preko 300%.
D. Berisavljević, N. Šušić, M. Joka
KONTROLA KVALITETA ŠIPOVA „SIT“ METODOM-PRIMERI IZ PRAKSE Pola veka na putevima, Novi-Pazar – put, Novi Pazar, 2012, 257-261. Rad ukazuje na značaj kontrole kvaliteta izvedenih šipova SIT metodom prikazom nekoliko slučajeva iz prakse. U radu su data ograničenja i oprema za ispitivanje integriteta šipova SIT (Sonic integrity test) metodom. Ključne reči: SIT, integritet, šip, signal. 84 Institut za ispitivanje materijala a.d. Beograd
M. Živanović, N. Šušić, K. Božić-Tomić
NEOPHODNOST PROJEKTANTSKOG NADZORA NAD IZVOĐENJEM SANACIJE KLIZIŠTA Pola veka na putevima, Novi-Pazar – put, Novi Pazar, 2012, 255-256. U našoj zemlji postoji mnogo klizišta (prema nepreciznim procenama 35.000- 36.000). U dnevnim novinama i stručnoj literaturi se pominju samo najveća, pri čemu se njihova veličina meri brojem ili značajem ugroženih - srušenih objekata ili veličinom površine pokrenute zemljane mase. Sa ostalim klizištima je upoznat mnogo uži krug ljudi, bilo da su to meštani koji žive u blizini ili na klizištu, ili stručnjaci koji imaju zadatak da projektuju ili izvode njegovu sanaciju. Periodično, posle dugih perioda kišnih padavina i/ili topljenja snega sa odmrzavanjem i zamrzavanjem što prouzrokuje vodozasićenje zemljanih masa, istovremeno se formira više klizišta u područjima izloženim ovim padavinama. Poslednji takav period je zabeležen 2005.-2006. godine. Mnogi putni pravci su tada bili na više deonica suženi ili čak i prekinuti, a mnoga domaćinstva su pretrpela velika oštećenja. Ne treba naglasiti koliko je, posebno u ovim okolnostima, hitno saniranje klizišta i povratak u redovno stanje.
M. Arsić, M. Mladenović, D. Jaković, Z. Kovačević, Z. Savić
OTPORNOST NA LOM POKLOPCA RADNOG KOLA TURBINE NA HIDROELEKTRANI ĐERDAP 1 XVIII Konferencija o međulaboratorijskim ispitivanjima materijala, Užice, Bela Zemlja, 2012, 42-46. Mehaničke osobine materijala predstavljaju samo polaznu osnovu za ocenu otpornosti na lom poklopca radnog kola turbine agregata A6 na hidroelektrani Đerdap 1, izrađenog od čeličnog liva 20GSL. Za ocenu njegovog integriteta i procenu veka neophodno je izvršiti i proračun čvrstoće (analitički, numerički) na osnovu naponskog stanja i u nekim slučajevima eksperimentalna ispitivanja parametara mehanike loma. U radu su dati rezultati analize hemijskoog sastava, merenja tvrdoće i metalografskih ispitivanja u uzdužnom i poprečnom preseku dva uzorka, isečenih iz epruveta ispitanih zatezanjem u Centralnoj laboratoriji fabrike LMZ (Sankt Peterburg, Rusija). Utvrđeno je da hemijski sastav ispitanih Pregled naučnih i stručnih rezultata u 2012. godini 85 uzoraka odgovara zahtevima standarda GOST 977/88, da tvrdoće po Vikersu (HV10) i po Brinelu HB 2,5/7500/20", kao i mikrotvrdoće po Vikersu (HV1) odgovaraju definisanim Tehničim uslovima, ali da oba uzorka imaju dendritnu mikrostrukturu, koja može da dovede do loma. Ključne reči: čelični liv 20 GSL, mehaničke osobine, otpornost na lom.
A. Terzić, Lj. Pavlović, Z. Radojević, Lj. Miličić, N. Mijatović, Z. Aćimović- Pavlović
INVESTIGATION OF HIGH TEMPERATURE INDUCED PROCESSES IN FLY ASH BASED COMPOSITES USING DTA METHOD 7th Symposium“Recycling Technologies and Sustainable Development“ with international participation, Soko Banja, Srbija, 2012, 17-23. Ispitivana su visoko-temperaturno otporna veziva na bazi otpadnih materijala. Pripremljne su dve kompozitne mešavine: prva je sadržala 70 % standardnog Portland cementa i 30 % letećeg pepela dobijenog sagorevanjem uglja, a druga 70 % visoko-aluminatnog cementa i 30 % letećeg pepela. Leteći pepeo je prethodno podvrgut mehano-aktivaciji. Reakcije dehidratacije i termička svojstva materijala su praćena od trenutka dodavanja vode (pri mešanju komponenti) do temperature na kojoj bi materijal bio normalno u funkciji. Termičke promene i sinterovanje kompozita na bazi letećeg pepela su praćeni metodom diferencijalne termičke analize (DTA) pri brzini zagrevanja of 10 ˚C/min. Pri tome temperature je povećavana od 20 do 1100 ˚C. Primećeno je da dodatak letećeg pepela utiče na sniženje temperature sinterovanja, ali ne menja odličnu termičku otpornost kompozita. Ključne reči: DTA, leteći pepeo, termička svojstva, cement, reciklaža.
V. Aleksić, B. Vistać, Lj. Milović
ISPITIVANJA TURBINSKIH VRATILA U FUNKCIJI DONOŠENJA ODLUKE O SANACIJI, 2 Održavanje 2012, Zenica, BIH, 2012, 73-80. Nakon preko 20 godina rada agregata na HE Đerdap II, u cilju utvrđivanja stanja turbinskih vratila izvršena su detaljna ispitivanja metodama IBR. Na svim 86 Institut za ispitivanje materijala a.d. Beograd vratilima utvrđene su površinske prsline različitih dužina i dubina, po čitavom obimu vratila, u zoni prelaznog radijusa, između cilindričnog dela vratila i velike prirubnice. Na jednom vratilu je utvrđena i prolazna prslina kroz koju je curilo ulje iz sistema regulacije. Materijal velike prirubnice sa mesta procurivanja je iskorišćen za izradu epruveta i mehanička ispitivanja radi utvrđivanja uzroka nastanka prolazne prsline na turbinskom vratilu. Na osnovu dobijenih rezultata i analiza pristupilo se izradi tehnologije sanacije vratila bez njihove demontaže. Do sada je uspešno sanirano 5, a u narednom periodu planira se sanacija još 3 vratila, dok su 2 zamenjena novim.
M. Vasić
PRIKAZ METODA ZA IZRAČUNAVANJE EFEKTIVNOG KOEFICIJENTA DIFUZIJE PRI SUŠENJU GLINENIH PROIZVODA 50. Savetovanje Srpskog hemijskog društva, 2012, Beograd, Srbija. U prošlosti a u nekom stepenu i današnjici, mnoge operacije sušenja su bile više zasnovene na praktičnom, iskustvenom znanju u odnosu na teorijski dostupna saznanja. U savremenom svetu, široko je prihvaćeno mišljenje da je nemoguće efikasno osušiti proizvode od gline bez posedovanja kompletnih i preciznih ispitivanja kako fizičko-hemijskih parametara same glinene sirovine tako i mehanizama transporta vlage unutar oblikovanih proizvoda. Složeni procesi istovremenog prenosa mase i energije, koji su često nestacionarnarnog karaktera, kao i različita priroda i osobine materijala (higroskopnost, kapilarnost, distribucija i veličina pora, pojava skupljanja prilikom sušenja i prslina prilikom sušenja glina i drugih keramičkih materijala) još više komplikuju opis načina procesa sušenja. Zbog toga jedinstvena teorijska postavka sušenja, koja bi univerzalno opisala ovaj proces za različite tipove glinenih materijala još uvek nije razvijena. Proces difuzije, posmatran kao transport materije usled nasumičnog kretanja molekula, je svojstven za sušenje. Tranfer vlage unutar čvrstog tela na određenoj temperaturi, obavlja se usled različitog sadržaja vlage u unutrašnjosti i na površini čvrstog tela. Brzina masenog transfera čistom difuzijom je prema tome proporcionalana gradijentu koncentracije sadržaja vlage, pri čemu difuzioni koeficijenat predstavlja faktor proporcionalnosti. Poznavanje difuzivnosti vlage proizvoda je ključno za proces simulacije i optimizacije procesa sušenja. Difuzivnost vlage je kompleksna i sistemski specifična funkcija koju pored čiste difuzije, karakteriše i postojanje Pregled naučnih i stručnih rezultata u 2012. godini 87 drugih, sekundarnih tipova unutrašnjeg masenog prenosa, kao što su površinska difuzija, Knudsenova difuzija kapilarni tok, isparavanje i kondenzacija, termodifuzija idr. koji u određenom manjem iznosu utiču na sveobuhvatni proces prenosa mase. Proces difuzije je najčešće najdominantniji transportni mehanizam prilikom sušenja opekarskih proizvoda1. Njegov matematički opis se karakteriše relativno jednostavanom i opšte poznatom jednačinom drugog Fikovog zakona. Opis celokupnog transporta vlage prilikom sušenja opekarskih proizvoda može se matematički opisati na isti način kao i proces čiste difuzije, s tim što se umesto koeficijenta difuzije uvodi efektivni koeficijenat difuzije, koji predstavlja zbirnu konstantu proporcionalnosti u zakonu difuzije, i koji u sebi sadrži sve moguće transportne mehanizme prenosa vlage kroz opekarski proizvod. U literaturi se srećemo sa malim brojem radova u kojima se razmatra proces sušenja samo keramičkih, odnosno glinenih materijala. Tako je Efremov2, proučavajući sušenje cigli, dao analitičko rešenje diferencijalne jednačine difuzije sa graničnim uslovima u formi fluksa. Nadovezujući se na ta istraživanja M. Vasić i saradnici3 su razvili model sušenja na osnovu modifikacije Efremove jednačine i kompjuterski program za određivanje efektivnog koeficijenta difuzije. Chemki i Zagrouba4 su ispitivali proces sušenja glina, a njihov doprinos se ogleda u izučavanju uticaja difuzionih koeficijenata, određenih na osnovu izgleda krivih sušenja, na proces sušenja. F. Zagrouba i saradnici5 su razvili model sušenja, pokušavši da opišu objedinjeni toplotni i maseni prenos, kao i deformacije koje nastaju prilikom sušenja pločastih uzoraka od gline. U njihovom radu je dat i prikaz načina određivanja vrednosti koeficijenta prenosa toplote i efektivnog koeficijenta difuzije. Zanden i Kerkhof6 su izvršili obimna istraživanja izotermskog transporta mase mehanizmima difuzije, isparavanja i kondenzacije, prilikom sušenja glinenih proizvoda. U radovima Skansija i saradnika7 date su osnove „fitovanja“ eksperimentalnih podataka sušenja glinenih crepova pomoću tankoslojnih modela, kao i određivanja efektivnog koeficijenta difuzije, koeficijenta preosa toplote i konstante sušenja.
A. Kostić, V. Radak, M. Vasić
INDUSTRIJA GLINENIH PROIZVODA XXXIX simpozijum o operacionim istraživanjima SYM-OP-IS, Beograd, 2012, 167-170. 88 Institut za ispitivanje materijala a.d. Beograd
U radu je prikazana proizvodnja glinenih proizvoda koji se izradjuju u Srbiji, kao grana industrije koja ostvaruje dinamički razvoj. Fokusirali smo se na uticaj regulative na proizvodnju sledećih proizvoda od gline: puna cigla, šuplja cigla, fasadna cigla, šuplji blokovi, monta blokovi i uložna cigla, zatim na ukupnu proizvodnju, kao i uticaj regulativa na prodaju ovih proizvoda na drugim tržištima. Primenom matematičkih modela u domenu vremenskih serija napravićemo projekciju proizvodnje za naredni period. Ključne reči: Proizvodi od gline, dekompozicija vremenske serije, deskriptivna statistika, test tačaka zaokreta,normalnost vremenske serije.
V. Jokić, A. Đorđević, J. Ćirilović
ASFALTNE MEŠAVINE SA DODATKOM GRANULATA RECIKLIRANE GUME PO “SUVOM” POSTUPKU – AKTUELNA ISKUSTVA 7. Simpozijum „Reciklažne tehnologije i održivi razvoj“, 7. SRTOR, Soko Banja, 2012. Granulat gume može biti upotrebljen u proizvodnji asfaltnih mešavina ili kao modifikator bitumenskog veziva („mokar“ proces), ili kao zamena za odreneni procenat kamenog agregata („suvi“ proces). U radu je dat opis “suvog” postupka proizvodnje asfaltnih mešavina sa osvrtom na aktuelna iskustva kod nas i u svetu. Takone su prikazani rezultati laboratorijskih ispitivanja prethodnog sastava asfaltne mešavine sa dodatkom granulata reciklirane gume po “suvom” postupku koja je proizvedena i ugranena 2011.godine na sportskim terenima OŠ “Dragan Lukić” na Novom Beogradu. Ključne reči: „suv“ proces, asphalt mixture, granulat gume. Pregled naučnih i stručnih rezultata u 2012. godini 89
SAOPŠTENJE SA SKUPA NACIONALNOG ZNAČAJA (M65)
M. Arsić, B. Vistać, Z. Odanović, V. Milčić, Z. Savić
METODOLOGIJA SANACIJE OŠTEĆENJA UNUTRAŠNJIH POVRŠINA KRIVAJA LOPATICA USMERNOG APARATA TURBINE A4 NA HIDROELEKTRANI ĐERDAP 1 Zavarivanje 2012, Divčibare, 8. U toku revitalizacije agregata A4 na hidroelektrani Đerdap 1, u cilju utvrđivanja stanja tubine izvršena su eksperimentalnim ispitivanjima metodama bez razaranja svih njenih delova. Tako su utvrđena oštećenja i prsline na unutrašnjim površinama krivaja lopatica usmernog aparata. Krivaje su izrađene od čeličnog odlivka oznake 25L. U radu je data metodologija sanacije oštećenjih unutrašnjih površina krivaja lopatica usmernog aparata. Metodologijom sanacije krivaja je, zbog njihovog konstrukcijskog rešenja i funkcije u eksploataciji, trebalo veliki broj detalja precizirati, pažljivo razmotriti i koordinisano izvršiti u cilju sigurnosti za njihovo ponovno korišćenje, jer ukoliko se samo neki od njih previde, podcene ili nepravilno sagledaju mogu nastati značajni problemi u radu kompletne turbine. Ključne reči: hidroturbina, krivaja, oštećenja, metodologija sanacije.
M. Arsić, D. Karišić, M. Mladenović, B. Vistać, Z. Savić
PRIMENA ISPITIVANJA BEZ RAZARANJA ZA TEHNIČKU DIJAGNOSTIKU STANJA I PROCENU INTEGRITETA TURBINSKEI HIDROMEHANIČKE OPREME IBR 2012, Divčibare, 8. Tehnička dijagnostika u slučaju turbinske i hidromehaničke opreme treba da se zasniva na određenim procedurama ispitivanja, istoriji upotrebe turbinske i hidromehaničke opreme hidroelektrana uz ekspertsko poznavanje konstrukcije i uslova rada, kao i analizi rezultata tima stručnjaka sa odgovarajućim iskustvom i znanjem iz oblasti projektovanja, konstruisanja, eksploatacije, održavanja, pouzdanosti, mehanike loma i dr. Degradacija osobina materijala i/ili zavarenih 90 Institut za ispitivanje materijala a.d. Beograd spojeva konstrukcija i delova turbinske i hidromehaničke opreme hidroelektrana izazvana je istovremenim uticajem velikog broja tehnološko - metalurških, konstrukcijskih i eksploatacijskih faktora. U radu je dato više primera gde su ispitivanja bez razaranja omogućila utvrđivanje uzroka degradacije osnovnog materijala ili zavarenih spojeva i identifikujaciju elementa neophodnih za ekspertsko odlučivenje o metodologiji koju treba primeniti za revitalizaciju delova turbinske i hidromehaničke opreme (reparaturno zavarivanje, primena novih materijala i tehnologija i izmena postojećih konstrukcionih rešenja) da bi se unapredile njihove tehničke karakteristike i produžio radni vek hidroagregata. Ključne reči: hidroturbina, ispitivanja bez razaranja , degradacije osnovnog materijala, integritet konstrukcija.
Pregled naučnih i stručnih rezultata u 2012. godini 91
6. DOKTORSKE DISERTACIJE I MAGISTARSKI RADOVI (M70)
ODBRANJENA DOKTORSKA DISERTACIJA (M71)
D. Nikolić
PRIMENA GENETSKIH ALGORITAMA U OPTIMIZACIJI GREDA OD BETONA VISOKIH I ULTRA VISOKIH ČVRSTOĆA SA ASPEKTA NOSIVOSTI NA SAVIJANJE I SMICANJE Fakultet tehničkih nauka Univerziteta u Novom Sadu, 2012. Istraživanja u okviru doktorske disertacije su pokazala da potencijalna opravdanost primene betona ultra visokih čvrstoća direktno zavisi od uspešnosti procesa optimizacije. U okviru eksperimentalnog rada dobijen je cementni kompozitni materijal sa čvrstoćom pri pritisku većom od 200 MPa, spravljen sa komercijalnim komponentnim materijalima dostupnim na domaćem tržištu. Na osnovu prikazanih odnosa granične nosivosti i jedinične cene grednog nosača primećuje se da povećan udeo čeličnih vlakana povećava mehanička svojstva UHPC, ali i dalje nedovoljno da bi mogla prihvatiti značajnije vrednosti opterećenja bez primene konvencijonalnog načina armiranja. U okviru eksperimentalnog rada prikazano je ponašanje greda od UHPC opterećenih na savijanje. Nakon dostizanja vrednosti čvrstoće pri zatezanju u najudaljenijem donjem vlaknu grede, pojavile su se prsline upravne na pravac dejstva zatežuće sile. Time je pokazano da UHPC u grednim nosačima ima sposobnost redistribuiranja napona unutar grede sve do pojave višestrukih prslina i čupanja vlakana iz cementne matrice. Na nosivost grede opterećene na savijanje utiče sadržaj čeličnih vlakana, ali bez primene klasične armature ili prethodnog naprezanja ne mogu se prihvatiti velika opterećenja. Primećeno je da sadržaj čeličnih vlakana znatno manje utiče na veličinu elastičnih deformacija u odnosu na izraženu vrednost krajnjih deformacija. Nosivost hibridnog preseka sa jednom trećinom visine od UHPC u donjoj zoni je odstupala za samo 15% u odnosu na gredu V2 spravljenu sa mešavinom US2Sf4. 92 Institut za ispitivanje materijala a.d. Beograd
Na osnovu prikazanih odnosa granične nosivosti i jedinične cene grednog nosača pokazano je da povećan udeo čeličnih vlakana povećava mehanička svojstva UHPC, ali i dalje nedovoljno da bi mogla prihvatiti značajnije vrednosti opterećenja bez primene konvencijonalnog načina armiranja. Izražena je višestruko veća nosivost pri primeni prednapregnute armature. Generalni zaključak je da primena UHPC bez primene prethodnog naprezanja kod grednih nosača nije ekonomski prihvatljiva. Pregled naučnih i stručnih rezultata u 2012. godini 93
7. PATENTI, AUTORSKE IZLOŽBE (M90)
REALIZOVANI PATENT, ARHITEKTONSKO, GRAĐEVINSKO ILI URBANISTIČKO AUTORSKO DELO (M92)
Ž. Kara-Pešić, P. Napijalo, G. Petrović
RASKLAPAJUĆA PRENOSIVA JEDINICA ZA STANOVANJE, RAD, POSLOVANJE, TRGOVINU, RAZNE USLUGE I SL.
Pronalazak se odnosi na rasklapajuću prenosivu jedinicu-kuću za stanovanje, rad, poslovanje, trgovinu i sl. koja se sastoji od dva zglobno spojena pod-kontejnera, odnosno dva osnovna dela, i različitih manjih pokretnih delova, koji su tokom transporta međusobno fiksirani u jedan monolitni veliki kontejner. Jedinica je izgrađena od metalnog skeleta i lake obloge. Pored toga što je uslov efikasnog utovara/istovara, lakoća elemenata dopušta njihovo rasklapanje i dovođenje u definitivan položaj pomoću radne snage koja nije snabdevena posebnim alatima, niti je za potrebne operacije posebno obučavana.
Pronalazak rešava problem lake prenosivosti (kako težinski, tako i dimenziono) svim raspoloživim sredstvima transporta više od pedeset kvadratnih metara korisne površine; brzog postavljanja na mesto, stavljanja pod krov i priključivanja na infrastrukturu (tokom jednog radnog dana); prevazilaženja oskudnog raspona svih poznatih kontejnerskih jedinica za boravak i svedene mogućnosti da se u tako tesnom prostoru razvije funkcija kojoj je namenjen, uveća upotrebna vrednost i organizuje dugotrajno korišćenje. 94 Institut za ispitivanje materijala a.d. Beograd 8. ORGANIZACIJA NAUČNO-STRUČNIH SKUPOVA
MEĐUNARODNI NAUČNO-STRUČNI SKUPOVI Istraživanja u oblasti građevinskih materijala i konstrukcija Međunarodna konferencija povodom obeležavanja 60 godina rada DIMK Srbije Građevinski fakultet Univerziteta u Beogradu, svečana sala, 19.10.2012. Organizator skupa: Institut IMS Suorganizator: Društvo za ispitivanje i istaživanje materijala i konstrukcija (DIMK) Srbije Društvo za ispitivanje i istraživanje materijala i konstrukcija Srbije je nastavilo rad ranijeg društva JUDIMK koje je nastalo iz Saveza jugoslovenskih laboratorija (SJL). Savez jugoslovenskih laboratorija je osnovan u Beogradu 1952. godine. Ove godine se navršava 60 godina uspešnog rada i tim povodom je DIMK Srbije donelo odluku da obeleži ovu godišnjicu organizovanjem jednodnevne međunarodne konferencije. Na konferenciji su eminentni predavači po pozivu prezentovali dostignuća i rezultate najnovijih istraživanja u oblasti materijala i konstrukcija zemalja regiona – sa prostora bivše Jugoslavije. Takođe, prezentovani su i pravci daljih istraživanja i razvoja novih materijala i konstrukcija u narednom periodu.
Pregled naučnih i stručnih rezultata u 2012. godini 95
Treće naučno-stručno međunarodno savetovanje „Zemljotresno inženjerstvo i inženjerska seizmologija“ Divčibare, 22-24.5.2012. Organizator skupa: Institut IMS Suorganizatori: Savez građevinskih inženjera Srbije, Beograd Društvo za zemlljotresno inženjerstvo Srbije, Beograd Saobraćajni institut CIP, Beograd Vujić Valjevo Naša zemlja spada u seizmički aktivna područja, pa se pri projektovanju i građenju objekata različite namene moraju primeniti propisi i metodologije kojima se obezbeđuje njihova seizmička otpornost. U tom smislu, u prvom redu, potrebno je korstiti adekvatne ulazne podatke koji zavise od lokalnih uslova terena i seizmičnosti pojedinih područja, a zatim i adekvatne metode projektovanja i građenja. U tom smislu koriste se informacioni sistemi, baze podataka, zapisi i iskustva iz dogođenih zemljotresa i tehnički propisi i preporuke pojedinih udruženja. Sada je veoma aktuelno prilagođavanje naših tehničkih propisa Evropskim normama – Evrokodovima EN 1998 iz 2004. godine. 96 Institut za ispitivanje materijala a.d. Beograd
DOMAĆI NAUČNO-STRUČNI SKUP SA MEĐUNARODNIM UČEŠĆEM Primena proizvoda od gline u izgradnji energetski efikasnih zgrada Institut IMS, svečana sala, 27.4.2012. Organizator skupa: Institut IMS Suorganizatori: Udruženje savremene industrije glinenih proizvoda (SIGP), Beograd Društvo za ispitivanje i istaživanje materijala i konstrukcija (DIMK) Srbije Zgrade u kojima je osnovni materijal opeka su najzastupljenije kako u prošlosti tako i u savremenoj građevinskoj praksi. Materijal proizveden na bazi gline je ekološki načistiji materijal, što sa aspekta zdravlja omogućava kvalitetno življenje u tako izgrađenim objektima. Veoma važan aspekt u izgradnji objekata je toplotna i i zvučna izolacija. Danas ciglarska industrija Srbije nudi proizvode različitih oblika i dimenzija sa malim koeficijentom toplotne provodljivosti. Njihova primena i kvalitetna ugradnja, uz preduzimanje ostalih mera, doprinosi racionalnoj potrošnji energije pri eksploataciji zgrada. Radove za ovaj skup pripremili su afirmisani stručnjaci i naučni radnici iz naše zemlje i inostranstva. Savetovanje prevashodno ima cilj da se projektantima i ugrađivačima ukaže kako primenom opeka, blokova i crepa, kao prirodnog materijala, u izgradnji zgrada može da se dobije kvalitetan i siguran objekat sa aspekta življenja, što podrazumeva kvalitetnu zaštitu od požara, dobru zvučnu i toplotnu izolaciju, to jest energetski efikasnu zgradu. Skup je okupio i vodeće proizvođače opeke, blokova i crepa, projektanske kuće i građevinska preduzeća koja izvode radove na izgradnji objekata gde se primenjuju navedeni proizvodi. Pregled naučnih i stručnih rezultata u 2012. godini 97
9. NAGRADE I PRIZNANJA
N. Šušić, D. Rakić
SANACIJA KLIZIŠTA UGRADNJOM GEO-STENTOVA (GEO-STENTS TO STABILIZE LANDSLIDES) 32. International Exhibition of Inventions, New Technologies, Design and Nations Cup of Young Innovation, 2012, Beograd. Srebrna medalja sa likom Nikole Tesle, Pronalazaštvo, 2012, Beograd Savez pronalazača i autora tehničkih unapređenja Beograda Klizišta zahtevaju svestrano proučavanje i istraživanje. Vrsta i obim proučavanja i istraživanja klizišta se prilagodjavaju veličini klizišta, opasnosti i šteti koju ona izazivaju. Pri rešavanju problema sanacije klizišta primenjuju se različita projektna rešenja. Izbor projektnog rešenja ne zavisi samo od uzroka klizanja, već i od tehničkih i ekonomskih mogućnosti izvodjenja sanacionih radova. U poslednje vreme ekonomski faktor postaje sve dominatniji pri izboru i izvodjenju mera sanacije. Da bi se sprečilo dalje klizanje terena potrebno je nekim merama povećati otpor tla, tj. ojačati zonu klizne površi. Ugradnjom novih geo-konstruktivnih elemenata, tj. geo-stentova postiže se ovaj efekat. Geo-stent je novi geo-konstruktivni element koga čine dva dela: valjkasti prstenovi i ispuna prstenova. Geo-stent se ugradjuje tako što se tehnikom bušenja postavljaju kontinualni valjkasti prstenovi (betonski, čelični i sl.) u zoni iznad i ispod klizne površi. Zatim se šupljina prstenova popunjava sa betonom, drobljenim agregatom ili šljunkom. Na ovaj način postiže se da se krutom konstrukcijom, geo-stentom, preseče klizna površ i time prihvati sila klizanja i prenese se u stabilno tlo ispod klizne površi. Geo-stentovi su ugradjeni i zarobljeni u tlo samo u zoni klizne površi (npr. po 2 m iznad i ispod klizne površi). Suština ugradnje geo-stentova je da oni prihvate sile klizanja i prenesu ih na stabilno tlo ispod klizne površi i na taj način ojačaju zonu klizne površi. Za razliku od standardnih načina sanacije klizišta gde ojačanje tla i konstrukcija se radi za celo tlo, od klizne površi pa do površine terena, geo-stentovi su 98 Institut za ispitivanje materijala a.d. Beograd konstrukcije i ojačanja tla samo u zoni klizne površi. Na taj način troši se mnogo manje materijala i rada pri izvodjenju sanacionih mera, pa samim tim su i troškovi mnogo manji.
Landslides need to be thoroughly researched and studied. The type and volume of research and study of a landslide will be adjusted to its size, threat and the damage it may cause. Designs for slide stabilisation may be different as related not only to the cause but also to the technical feasibility and economic practicability. The selection of the works and their construction is increasingly depending on the economic factor. A landslide will be prevented by increasing the soil resistance or strengthening the zone of the sliding surface. This effect may be accomplished by incorporation of new geo-structural elements, the geo-stents. Geo-stent is a new geo-structural element composed of tube-rings and filling. The tube-rings, or short cylindrical (concrete, steel or the like) units, are incorporated in a bored hole through the zone above and beneath the sliding surface, and then filled with concrete, crushed aggregate or gravel. This rigid structure, geo-stent, through the sliding surface is receiving the sliding force and transferring it into the stable soil under the sliding surface. Geo-stents are incorporated and captured only in the sliding surface zone (for example, two above and two under the sliding surface). The function of geo-stents is essentially in receiving the sliding forces and transferring them into stable soil under the sliding surface, thus reinforcing the weak sliding zone. Unlike the conventional soil stabilizations, designed to strengthen the whole mass of soil from the sliding to the ground surface, geo- stents are constructions and soil reinforcement in the sliding surface zone alone. They use less material and labour and thus are more cost-effective. Pregled naučnih i stručnih rezultata u 2012. godini 99
10. NAUČNI PROJEKTI FINANSIRANI OD STRANE MINISTARSTVA PROSVETE I NAUKE
Ev. Naziv projekta broj
Tehnološki razvoj
35002 Razvoj novih metodologija Dr Miodrag Arsić, revitalizacje turbinske i rukovodilac projekta hidromehaničke opreme Dr Vencislav Grabulov hidroelektrana u zavisnosti od uzroka degradacije materijala Dr Zoran Odanović Nebojša Milovanović
36014 Geotehnički aspekti istraživanja Dr Nenad Šušić, i razvoja savremenih tehnologija rukovodilac projekta građenja i sanacija deponija Mr Ksenija Đoković komunalnog otpada Dušan Berisavljević
36017 Istraživanje mogućnosti primene Dr Aleksandra Mitrović otpadnih i recikliranih materijala Dr Ksenija Janković u betonskim kompozitima, sa ocenom uticaja na životnu Dragan Nikolić sredinu, u cilju promocije Dragan Bojović održivog građevinarstva u Srbiji Ljiljana Lončar
35011 Integritet opreme pod pritiskom Mr Dejan Momčilović pri istovremenom delovanju Mr Vujadin Aleksić zamarajućeg opterećenja i temperature 100 Institut za ispitivanje materijala a.d. Beograd
35006 Održivost i unapređenje Dr Miodrag Arsić mašinskih sistema u energetici i
transportu primenom forenzičkog inženjerstva, eko i robust dizajna
35029 Razvoj metodologija za Mr Dejan Momčilović povećanje radne sposobnosti,
pouzdanosti i energetske efikasnosti mašinskih sistema u energetici
35040 Razvoj savremenih metoda Željko Flajs dijagnostike i ispitivanja
mašinskih struktura
Integralni projekti
45008 Razvoj i primena Dr Zagorka Radojević multifunkcionalnih materijala na Dr Anja Terzić bazi domaćih sirovina modernizacijom tradicionalnih Milica Arsenović tehnologija Miloš Vasić Ljiljana Miličić Ivana Delić
Osnovna istraživanja
186010 Minerali Srbije: sastav, struktura, Dr Snežana Dević geneza, primena i doprinos održanju životne sredine
172005 Uticaj nano i mikrostrukturnih Dr Zoran Odanović konstituenata na sintezu i karakteristike savremenih kompozitnih materijala sa metalnom osnovom Pregled naučnih i stručnih rezultata u 2012. godini 101
174004 Mikromehanički kriterijumi Dr Vencislav Grabulov oštećenja i loma
172057 Usmerena sinteza, struktura i Dr Anja Terzić svojstva multifunkcionalnih materijala
102 Institut za ispitivanje materijala a.d. Beograd Pregled naučnih i stručnih rezultata u 2012. godini 103
ODABRANE STRUČNE REFERENCE 104 Institut za ispitivanje materijala a.d. Beograd ODABRANE STRUČNE REFERENCE
U ovom odeljku dat je pregled ključnih usluga koje je Institut IMS izvršio u 2012. godini. U skladu sa multidisciplinarnom organizacijom Instituta, usluge obuhvataju izradu investiciono-tehničke dokumentacije, ispitivanja na terenu i u laboratorijama, stručni nadzor nad izvođenjem radova, studije, ekspertize i drugo u praktično svim oblastima građevinarstva i energetike. Pregled referenci dat je po organizacionim celinama.
CENTAR ZA MATERIJALE
R.b. Referenca
Laboratorija za kamen i agregat
1. Laboratorijsko ispitivanje u cilju realizacije geoloških istraživanja ležišta kamena, šljunka i peska
2. Ispitivanje istorijskih maltera (Viminacijum, Pećka Patrijaršija)
3. Brojne analize kamena i kamenog agregata
4. Ispitivanje uzoraka sa fasade zgrade Narodnog muzeja u Beogradu
Pregled naučnih i stručnih rezultata u 2012. godini 105
106 Institut za ispitivanje materijala a.d. Beograd
Laboratorija za građevinsku keramiku
5. Elaborat o oceni kvaliteta opekarske sirovine sa ležišta Crvenačka kosa ciglane IGM Jedinstvo, Crvenka
6. Studija o oceni kvaliteta opekarske sirovine, definisanje parametara procesa proizvodnje opekarskih proizvoda u ciglani u Srpskom Miletiću
7. Studija o utvrđivanju prirode i uzroka defekata na vidnoj površini keramičkih pločica sa fasade građevinskog objekta Banja komerc u Aranđelovcu
8. Veštačenje za Privredni sud u Somboru – Nalaz sa mišljenjem o količini zemlje koja je utrošena za proizvodnju opekarskih proizvoda u periodu 2006 - 2009. godina u jednoj domaćoj ciglani
9. Veštačenje za Viši sud u Somboru – Nalaz sa mišljenjem o količini pune opeke koja može da se proizvede od definisane količine zemlje u konkretnoj ciglani (nizak nivo tehnologije i opreme) Pregled naučnih i stručnih rezultata u 2012. godini 107
Laboratorija za beton
10. Početni nadzor fabrike i fabričke kontrole proizvodnje za SC Europrefabricate, Temišvar, Rumunija
11. Prethodna ispitivanja, kontrola kvaliteta betona i sastavnih delova betona na izvođenju radova na projektu: Obilaznica oko Beograda, deonica Dobanovci-Bubanj Potok, za Energoprojekt-Niskogradnja, Beograd
12. Kontrola kvaliteta betona na RTB Bor, za Energoprojekt- Visokogradnja , Bor
13. Kontrola kvaliteta betona na mostu preko reke Pek u selu Miljevići za Ingrap-omni, Valjevo
14. Pomoćni nadzor za praćenje betonskih radova na rehabilitaciji postojećih mostova na deonici Paraćin – Straža od km 742+289 do km 766+358, za JP Putevi Srbije
15. Isptivanja sastavnih delova betona i betona za betonsku bazu u Preševu, na deonici Autoputa Levosoje-granica BRJ Makedonija, Putevi Užice
16. Projekat betona za objekat MHE Ljuti Do, za Energy & Construction Park
17. Projekat betona za objekat Centralno postrojenje za prečišćavanje otpadnih voda Vrbas i Kula u Vrbasu, za Millennium team, Vrbas
18. Projektovanje betonskih mešavina za objekat Drumsko - železnički most (Žeželjev most), Novi Sad, za TKK, Srpenica, Slovenija
19. Naknadno utvrđivanje kvaliteta betona u konstrukciji za objekat Javna garaža Zaječar, za Kolubara
20. Naknadno utvrđivanje kvaliteta betona u konstrukciji za objekat Hotel Grand, Kopaonik za MK Mounteen Resort 108 Institut za ispitivanje materijala a.d. Beograd
21. Naknadno utvrđivanje kvaliteta betona u konstrukciji za objekat Kompleks FCC Rafinerija nafte Pančevo, za Steel Plus
22. Proizvodna sposobnost fabrike betona za Lafarge beton, Zemun
23. Završne ocene kvaliteta betona za objekte izvedene u Srbiji za firmu Širbegović grupa – GMT Konstrukcije, Gračanica, BiH
24. Završne ocene kvaliteta betona za montažnu konstrukciju poslovnog objekta Proma factory LOT 3, Kragujevac, za IMP Balkan
25. Elaborat o tehničkom nadzoru u procesu proizvodnje prefabrikovanih konstruktivnih elemenata za montažnu konstrukciju poslovnog objekta Inveco Dztech, Niš, za IMP Balkan
26. Kontrola kvaliteta betona na projektu Most Zemun-Borča, za China Road and Bridge Corporation – Serbia
Laboratorija za akustiku i vibracije
27. Monitoring buke i akustično zoniranje na području grada Pančeva
Pregled naučnih i stručnih rezultata u 2012. godini 109 110 Institut za ispitivanje materijala a.d. Beograd CENTAR ZA METALE I ENERGETIKU
R.b. Referenca Investitor
1. Ispitivanje i ocena stanja turbinske i PD HE Đerdap d.o.o. hidromehaničke opreme agregata A4 HE Đerdap 1, IBR (VT, VTδ, MT, PT UT, RT, HT, Kladovo Replika) IR (mehaničko-tehnološke osobine, hemijski sastav, metalografija) Prijem opreme i kontrola tehničke dokumentacije hidroagregata i generatora u fabrikama u Srbiji i inostranstvu Izrada tehnologije zavarivanja, izbor elektrode i ispitivanje metala šava, ispitivanje za WPS procena preostalog veka konsalting usluge
2. Reparacija – popravka prelaznog radijusa PD HE Đerdap d.o.o. turbinskih vratila A5 HE Đerdap 2, Reparaturno zavarivanje turbinskog vratila Negotin Kaplan turbine, sa IBR ispitivanjem (VT, VTδ, MT, PT, UT, HT, Replika)
3. Ispitivanje bez razaranja na tekućem i PD TE Nikola Tesla interventnom održavanju postrojenja d.o.o., ogranak B Ušće
Pregled naučnih i stručnih rezultata u 2012. godini 111 112 Institut za ispitivanje materijala a.d. Beograd
4. Ispitivanje i ocena stanja turbinske i PD HE Đerdap d.o.o. hidromehaničke opreme agregata A1 i A2 HE Pirot, Pirot IBR (VT, VTδ, MT, PT UT, RT, HT, Replika) Ispitivanje i ocena stanja dovodnog cevovoda
5. Ispitivanje metala metodama sa i bez PD TE Nikola Tesla razaranja opreme i parovoda d.o.o., IBR (VT, VTδ, MT, PT, UT, RT, HT, TE Kolubara A, Veliki Replika) Crljeni IR (mehaničko tehnološke osobine, hemijski sastav, metalografija) Prijem opreme i kontrola tehničke dokumentacije
6. Usluge ispitivanja metala sa i bez razaranja Kontrol Inspekt d.o.o. – Panpnske termoelektrane i toplane – Novi Beograd Sad
7. Ispitivanje metala bez razaranja na terenu i PD TE KO Kostolac ispitivanje metala sa razaranjem za potrebe d.o.o., TERMOELEKTRANE „B“ i KOPA TE Kostolac B, DRMNO u 2012 god. Kopovi, Drmno Parovodi B1 i B2 (RA, RB, RC), napojna voda (RL), međupovezni parovodi (MP1- MP2 i P2-P3) IBR (VT, VTδ, MT, PT, UT, RT, HT, Replika) IR (mehaničko tehnološke osobine, hemijski sastav, metalografija)
Pregled naučnih i stručnih rezultata u 2012. godini 113 114 Institut za ispitivanje materijala a.d. Beograd
8. IBR (VT,MT,PT, UT) i nadzor pri DSD Noell – Vircburg, zavarivanju pri izradi donjeg prstena Nemačka usmernog aparata agregata A5 za HE Đerdap 1
9. Ispitivanje metodama bez razaranja opreme PD TE KO Kostolac rotornih bagera i ispitivanje metodama sa d.o.o., razaranjem po dostavljenom uzorku na PK TE Kostolac A, Drmno Kostolac IBR (VT, VTδ, MT, PT, UT, RT, HT, Replika) IR (mehaničko tehnološke osobine, hemijski sastav, metalografija) Prijem opreme i kontrola tehničke dokumentacije
10. Kontrolisanje metodama IBR PD HE Đerdap d.o.o., (VT,MT,PT,UT) i IR (mehaničko- HE Đerdap 1, Kladovo tehnološke osobine) pri izradi lopatica radnog kola i lopatica usmernog aparata agregata A4 u Litostroju, Ljubljana, Slovenija
11. Kontrolisanje metodama IBR PD HE Đerdap d.o.o., (VT,MT,PT,UT) i IR (mehaničko- HE Đerdap 1, Kladovo tehnološke osobine) pri izradi turbinskog poklopca agregata A4 u Bruno Presezzi-u, Milano, Italija
12. Utvrđivanje stanja račve A6 cevovoda na EP CG, HE Perućica, HE Perućica Nikšić, Crna Gora IBR (VT, MT, PT, UT, RT), IR (mehaničko- tehnološke osobine) procena preostalog veka Pregled naučnih i stručnih rezultata u 2012. godini 115
CENTAR ZA PUTEVE I GEOTEHNIKU
Odeljenje za geotehniku R.b. Referenca Investitor 1. Ispitivanje šipova opitom statičkog probnog Fundament, Deneza M, opterećenja na lokacijama: PMC Inženjering, Most Zemun – Borča, Energoprojekt, Ratko Mitrović Dedinje, SET naselja StepaStepanović i Nanocentar u Šabac, Napred, Beogradu Gradina, Grading 2. Ispitivanje Integriteta šipova metodom Deneza M, Geosonda, SIT-a na lokacijama: PMC Inženjering, Žeželjev most u N.Sadu, naselja Stepa Grading, Exing b&p, Stepanović, dr Ivana Ribara, obilaznica oko RatkoMitrović Beograda, niskogradnja, 3. Dilatometarska ispitivanja na lokacijama: RB Kolubara d.o.o. odlagalište PK Tamnava – Istočno polje, MK Fintel wind Vetropark Plandište,
4. Geotehnička ispitivanja i izrada geotehničke Elektromreža Srbije dokumentacije za potrebe izgradnje Trafo stanica u Srbobranu i Smederevu 5. Geotehnička ispitivanja i izrada Geotehničke dokumentacija za potrebe izgradnje Mašinoprojekt kompleksa Ikea na B.Kosi – Novi Beograd
6. Geotehnička dokumentacija analize Leisure group stabilnosti padine za potrebe izgradnje Plaza centra u Beogradu 116 Institut za ispitivanje materijala a.d. Beograd
Odeljenje za projektovanje
6. Veštačenje o tehničkoj ispravnosti i JP Putevi Srbije ispunjenosti uslova za upotrebu izvedenog objekta, I faza radova Auto-put E-70/E-75 Obilaznica Beograda deonica Dobanovci- Bubanj Potok: Sektori 1,2 i 3
7. Veštačenje o tehničkoj ispravnosti i JP Koridori Srbije ispunjenosti uslova za upotrebu izvedenog objekta, I faza radova Auto-put E-70/E-75 Obilaznica Beograda deonica Dobanovci- Bubanj Potok: Sektor 4
8. Tehnička kontrola glavnih projekata druge JP Putevi Srbije faze radova Auto-put E-70/E-75 Obilaznica Beograda deonica Dobanovci-Bubanj Potok: Petlja Orlovača, Petlja Petlovo Brdo i Sektor 3 zona mosta
Odeljenje za nadzor i terenska ispitivanja
9. Nadzorna asfaltna i geomehanička JP Putevi Srbije laboratorija na rehabilitaciji magistralnog puta M-5, deonica Paraćin - Zaječar
10. Nadzorna asfaltna i geomehanička Eptisa laboratorija na izgradnji autoputa E-80, deonica: Niš-Dimitrovgrad
11. Stručno-tehnički nadzor na održavanju, Direkcija za izgradnju rekonstrukciji i izgradnji lokalnih i grada Sombor nekategorisanih puteva na teritoriji opštine Sombor
12. Terenska asfaltna i geomehanička ispitivanja Beogradput, Putevi prilikom izgradnje državnih puteva I i II Užice,Vojput Subotica, reda, lokalnih i gradskih saobraćajnica Kolubara Gradjevinar
Pregled naučnih i stručnih rezultata u 2012. godini 117 118 Institut za ispitivanje materijala a.d. Beograd
Laboratorija za puteve i geotehniku 13. Laboratorijska kontrolna geomehanička Roughton international ispitivanja i nadzor na rehabilitaciji 160 km magistralnih puteva u Srbiji
14. Laboratorijska geomehanička ispitivanja za Građevinski fakultet potrebe izgradnje vetrogeneratora na terenu Vetroparkova Košava i Plandište
15. Laboratorijska geomehanička ispitivanja za Srbija gas potrebe izrede idejnog i glavnog projekta za Institut za magistralni gasovod „Južni tok“ na teritoriji vodoprivredu Republike Srbije Jaroslav Černi
16. Kontrolna geomehanička ispitivanja China Road and Bridge pristupnih puteva mostu Zemun –Borča Corporation Serbia Branch
17. Kontrolna geomehanička ispitivanja Vlado Baumachinen pristupnih puteva mostu na Adi
Pregled naučnih i stručnih rezultata u 2012. godini 119
CENTAR ZA KONSTRUKCIJE I PREDNAPREZANJE
Odeljenje za prednaprezanje R.b. Referenca Investitor 1. Izvršeni radovi prednaprezanja Silos br.3 cementnog klinkera cementare Radnik gradnja, Kakanj, BIH Lukavac Nadvožnjaci i mostovi na koridoru X, Alpine d.o.o. Beograd deonica Sukovo-Dimitrovgrad Bulevar Evrope u Novom Sadu Inter-kop, Šabac Nadvožnjaci na deonici LOT A2 Inter-kop, Šabac Dobanovci-Batajnica Most Obarska kod Bijeljine PGP Graditelj, Bijeljina 2. Primena sistema prednaprezanja Instituta IMS Sanacija mosta Gazela sa prilaznim Mostogradnja, konstrukcijama Beograd Koridor XI, deonica Ub – Lajkovac Putevi Užice Stambeno-poslovni objekat u Osijeku Gradnja, Osijek (IMS tehnologija građenja)
120 Institut za ispitivanje materijala a.d. Beograd
Odeljenje za arhitektonsko i građevinsko projektovanje R.b. Referenca Investitor 1. Revitalizacija IMS tehnologije građenja u Gradnja Osijek pogonu Gradnja Osijek Nadzor, tehnička pomoć, obuka u proizvodnji i u izgradnji pilot-objekta Potvrđivanje usaglašenosti proizvedenih elemenata sa tehničkim specifikacijama 2. Nadzor nad izvođenjem radova Most preko reke Pepeljuše kod JP Putevi Srbije Aleksandrovca MHE Džep, Vladičin Han NEPC, Surdulica MHE Ljuti Dol, Bosilegrad NEPC, Surdulica
Pregled naučnih i stručnih rezultata u 2012. godini 121 122 Institut za ispitivanje materijala a.d. Beograd
Odeljenje za sanacije R.b. Referenca Investitor 1. Projekti sanacije mostova Most na autoputu E75 preko saobraćajnice JP Putevi Srbije T6 u Beogradu Most na autoputu E75 kod KBC u Beogradu JP Putevi Srbije Most na autoputu E75 kod Hitne pomoći u JP Putevi Srbije Beogradu 2. Glavni projekat rekonstrukcije mosta Češka JP Putevi Srbije ćuprij” na kanalu Bezdan – Vrbas, na prostoru KO Bački Monoštor sa rekonstrukcijom saobraćajnice od L-405 do mosta i od mosta do Bačkog Monoštora 3. Pregled konstrukcije i obezbeđivanje Energoprojekt-Oprema podataka za izradu glavnog projekta sanacije krune kotla bloka 2 TE Kostolac
Pregled naučnih i stručnih rezultata u 2012. godini 123 124 Institut za ispitivanje materijala a.d. Beograd
Laboratorija za ispitivanje konstrukcija R.b. Referenca Investitor 1. Ispitivanje probnim opterećenjem mosta Putevi Užice preko reke Zapadna Morava u Kraljevu 2. Ispitivanje grupe ab. mostova probnim Inter-kop opterećenjem u sklopu Dobanovačke petlje 3. Ispitivanje ankera antenskih stubova na više Kodar inženjering, lokacija Amiga, Kraljevo 4. Ispitivanje geotehničkih sidara u sklopu HE Georad Trebinje 5. Ispitivanje grupe čeličnih mostova probnim Ingrap-Omni Valjevo opterećenjem na više lokacija 6. Ispitivanje prilaznih čeličnih konstrukcija GP Mostogradnja u probnim opterećenjem u sklopu mosta restruktuiranju "Gazela" u Beogradu 7. Ispitivanje probnim opterećenjem glavnog GP Mostogradnja u raspona mosta "Gazela" u Beogradu restruktuiranju 8. Ispitivanje ankera na zvučnim barijerama MBA Miljković kod Careve ćuprije 9. Merenje težine bagera S400 Prim d.o.o Kostolac 10. Ispitivanje rešetkastog krovnog čeličnog FinalProm d.o.o nosača u okviru Aqua park-a u Bijeljini Bijeljina 11. Ispitivanje probnim opterećenjem mosta Putevi Užice preko reke Zapadna Morava u Kraljevu 12. Ispitivanje ankera konstrukcije spuštenog Framaco Kolin Epik, plafona na Kompleksu objekata Nove USA Beograd ambasade u Beogradu
Pregled naučnih i stručnih rezultata u 2012. godini 125 126 Institut za ispitivanje materijala a.d. Beograd
13. Ispitivanje nosećih fasadnih i krovnih Trimo inženjering, sendvič panela sa ispunom od Beograd polyisocyanurate 14. Ispitivanje prstenaste krutosti spiralno Krušik plastika, motanih cevi prečnika 2500mm Osečina
Pregled naučnih i stručnih rezultata u 2012. godini 127 128 Institut za ispitivanje materijala a.d. Beograd SERTIFIKACIONO TELO
R.b. Referenca Sertifikacija proizvoda prema harmonizovanim evropskim standardima – Redovni nadzor fabrike i fabričke kontrole proizvodnje (FPC) 1. ROCKWOOL ADRIATIC, Potpićan, Hrvatska 2. URSA SLOVENIJA, Novo Mesto, Slovenija 3. TRIMO INŽENJERING, Beograd, Srbija 4. S.C. EUROPREFABRICATE S.R.L., Rumunija
Pregled naučnih i stručnih rezultata u 2012. godini 129 130 Institut za ispitivanje materijala a.d. Beograd FOTOGRAFIJE
Fotografije su iz arhiva Instituta IMS. Strana 105. Detalj laboratorijske opreme, autor G. Petrović. Strana 109. Stubovi mosta Zemun – Borča u izgradnji, arhiva Laboratorije za beton. Strana 111. Detalj, arhiva Centra za metale i energetiku. Strana 113. Peskarenje, autor M. Drča. Strana 117. Detalj, arhiva Centra za puteve i geotehniku. Strana 121. IMS konstrukcija u fazi montaže u Osijeku, autor N. Milovanović. Strana 123. Ispitivanje konstrukcije Aqua parka u Bijeljini, autor V. Mladenović. Strana 125. Ispitivanje konstrukcije mosta Gazela, snimak iz helikoptera (www.helivideo.rs). Strana 127. Ispitivanje konstrukcije mosta Gazela, arhiva Laboratorije za ispitivanje konstrukcija. Strana 129. Ispitivanje fasadnih sendvič-panela, arhiva Laboratorije za ispitivanje konstrukcija.