DOCSLIB.ORG

Simulation of Cement Grinding Process for Optimal Control of SO3…, Chem

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Simulation of Cement Grinding Process for Optimal Control of SO3…, Chem D. TSAMATSOULIS, Simulation of Cement Grinding Process for Optimal Control of SO3…, Chem. Biochem. Eng. Q., 28 (1) 13–25 (2014) 13 Simulation of Cement Grinding Process for Optimal Control of SO3 Content * D. Tsamatsoulis Original scientific paper Halyps Building Materials S. A., Italcementi Group, Received: April 25, 2013 17th Klm Nat. Rd. Athens – Korinth, 19300, Greece Accepted: July 31, 2013 The control of cement grinding/mixing process in an industrial mill regarding SO3 content has been effectively simulated taking into account all its fundamental sides and particularities. Based on a simulator, two controllers of different philosophy have been studied: A classical proportional-integral (PI) controller as well as a nonlinear one (step changes, SC) consisting of certain classes of SO3 output ranges that result in certain lev- els of discrete corrections of gypsum feed. Initially, the simulator was implemented for grinding of a single cement type each time. Totally, three cement types were investigated. The controllers have been parameterized and compared using the minimal standard devi- ation of SO3 as a criterion. Both provided satisfactory SO3 consistency, but PI was more efficient against SC as with the double sampling period, the same minimum standard deviation was obtained leading to equal results with half the sampling actions. The sim- ulation was also realized in milling of several cement types. A feedforward part was added to the feedback loop to face the case of cement type changing. The results of op- eration of this kind of controller in an industrial milling system contribute greatly to the improvement in cement quality. Key words: Regulation, cement, sulphates, dynamics, mill, grinding, uncertainty, simulation Introduction addition of an excessive amount of gypsum leads to detrimental expansion of concrete and mortar. Cement is produced by co-grinding clinker, The optimum gypsum content in cement has gypsum and other components defined in the Ce- been investigated by several researchers due to its ment Standards like limestone, pozzolans, fly ash importance. Lerch,3 in his excellent study, found and slag. The grinding is usually performed in hor- that the optimum sulphates content in cement, with izontal ball mills. Gypsum is typically the basic respect to mortar strength, is closely related to vari- source of sulphates (SO3) in the cement. The effect ous parameters like hydration heat, length changes of gypsum on the cement quality is critical and two- of mortar specimens cured in water, alkalis, C3A fold. It affects two of the main properties of this content, and cement fineness. The influence of SO3 product, setting time and strength.1 For this reason on the hydration of the cement mineral phases has gypsum is added during cement grinding in the mill been investigated by several researchers.3–6 Soroka feeding, requiring a weight feeder of high accuracy. et al.4 concluded that gypsum accelerates the rate of Clinker is mainly composed of four mineral phases: hydration, when its addition is below the optimum Tricalcium silicate (3CaO ∙ SiO2 or C3S), dicalcium SO3 content, but produces significant retardation silicate (2CaO ∙ SiO2 or C2S), tricalcium aluminate when the addition exceeds the optimum. Jansen 5 (3CaO ∙ Al2O3 or C3A) and tetracalcium alumino- et al. analysed the changes detected in the phase 2 ferrite (4CaO ∙ Al2O3 ∙ Fe2O3 or C4AF). Bogue in composition during the hydration process. They an historical study, established the mathematical concluded that the cement phases involved in the formulae for the calculation of the clinker com- aluminate reaction (bassanite, gypsum, anhydrite pounds – C3S, C2S, C3A, C4AF – and presented data and C3A) reacted successively. Several researchers for the heat of hydration of these compounds. have also investigated the impact of limestone addi- During cement hydration, one of its main mineral tion to the hydration process and sulphates opti- phases, tricalcium aluminate, reacts with water at a mum.7–8 Tsamatsoulis et al.9 determined the effect high rate, which could result in a false set. Gypsum of cement composition and mortar age on the opti- addition slows down this fast and exothermic reac- mum sulphates content using as criterion the maxi- tion and false set is prevented during the concrete mization of compressive strength. Extensive exper- production, transfer and placing. Conversely, the imentation has been performed to achieve this purpose by utilizing four cement types and measur- *Corresponding author: e-mail: [email protected] ing the strength at ages ranging from 2 days up to 14 D. TSAMATSOULIS, Simulation of Cement Grinding Process for Optimal Control of SO3…, Chem. Biochem. Eng. Q., 28 (1) 13–25 (2014) 63 months. The compressive strength is correlated Process simulation with the ratio of sulphates to clinker content, SO3/CL. Odler10 presented a review of existing correlations The control and regulation of grinding process between cement strength and basic factors related to regarding the SO3 content is performed by sampling several properties of the cement and clinker. One of cement in the mill outlet, measuring the SO3 con- these factors is the sulphates content of the cement. tent, and changing the gypsum percentage in the Kheder et al.11 found also a significant correlation cement feed composition. The simulation involves between strength and cement SO3 content in their all the basic components of the process: The trans- multivariable regression model. fer functions of SO3 within the mill circuit, cement While extensive literature exists about the posi- sampling and measurement, and the control func- tion of the optimum SO3 and its relation with several tion applied. A simplified flow sheet, showing the cement characteristics, there is limited information basic components of a closed grinding system is about the regulation of gypsum in the actual produc- presented in Fig. 1. The raw materials via weight tion process, so that the values of SO3 are continu- feeders are fed to the ball mill (CM). The product ously near the target. Such research is provided by of the mill outlet is directed through a recycle Dhanial et al.12 by studying the automatic control of elevator to a dynamic separator. The high fine- cement quality using on-line XRD. Efe13 also, by de- ness stream of the separator constitutes the final veloping a multivariable control of cement mills in product, while the coarse material returns to CM the aim to control the process, states that the SO3 to be ground again. The block diagram and trans- content is one of the main parameters determining to fer functions of the grinding process concerning what extent the final product satisfies desired specifi- the control of SO3 content are shown in Fig. 2. cations. For the cement industry, it is not sufficient to The blocks represent the subsequent sub-processes: find the optimum gypsum content in the laboratory: GP = mixing of materials inside the milling installa- Such research must then be applied to the industrial tion; GS = cement sampling; GM = SO3 measure- scale process. The objective of this study is to inves- ment; GC = controller. The signals of the feedback tigate the control functions for regulation and control of the sulphates content in industrial cement milling. Optimization (i.e. parameter identification) of control functions was performed by simulating the grinding process in cement mill No 6 (CM6) of Halyps plant regarding the sulphates content. Actual analyses of the raw materials had been taken into account, in- cluding their uncertainty. Three cement types conforming to the norm EN 197–1 : 2011 were utilized: CEM A-L 42.5 N, CEM II B-M (P-L) 32.5 N, CEM IV B (P-W) 32.5 N. Their characteristics according to the mentioned norm are Fig. 1 – Closed circuit grinding system provided in Table 1. The results of Tsamatsoulis9 models, derived from the same cement types pro- duced in the same plant, were also taken into account to determine the SO3 target per cement type. Table 1 – Cement types conforming to EN 197–1:2011 CEM Type Composition and Strength A-L 42.5 B-M (P-L) IV B (P-W) N 32.5 N 32.5 N %Clinker ≥80 ≥65 ≥45 %Fly Ash ≤55 %Pozzolane ≤35 %Limestone ≤20 Maximum %SO3 3.5 3.5 3.5 Minimum 28 days Strength 42.5 32.5 32.5 (MPa) Gypsum is not included in the composition but added according to SO3 target Fig. 2 – Block diagram of the SO3 regulation feedback loop D. TSAMATSOULIS, Simulation of Cement Grinding Process for Optimal Control of SO3…, Chem. Biochem. Eng. Q., 28 (1) 13–25 (2014) 15 loop are denoted with the following symbols: %G, as follows: Gypsum SO3 is assumed constant for a %CL, %FA = percentage of gypsum, clinker and time interval TConst,G, not exactly determined, but fly ash respectively. %SO3 = cement sulphates. considered to be within the interval [TMin,G, TMax,G]. %SO3_S, % SO3_M = SO3 of the sampled and Then, by utilizing a random generator, a number, measured cement correspondingly. %SO3_T = x, between 0 and 1 is selected. To find the inter- sulphates target. e = %SO3_T – %S O3_M. d = val of constant SO3 of gypsum, formula (1) is ap- plied. feeders disturbances. n = noise of the SO3 measure- ment. (TTMax., G Min G 1) TConst, G Int (1) Description of the simulator xTMin, G Three raw materials contain SO3: Clinker, The calculation of the periods T is continued gypsum and fly ash. A complete series of analyses Const,G until TT In case this sum is greater, the has been considered and the mean values and Const, G Tot last T is truncated to be TT . standard deviations of sulphates have been comput- Const,G Const, G Tot ed to be used in the simulation. When gypsum is The next step is to determine the SO3 of gyp- changing, pozzolane or limestone is changing si- sum fed during TConst,G.
Load more

Recommended publications
  • Environmental, Health, and Safety Guidelines for Cement and Lime Manufacturing
    Environmental, Health, and Safety Guidelines CEMENT AND LIME MANUFACTURING WORLD BANK GROUP DRAFT FOR PUBLIC CONSULTATION—AUGUST 2018 Environmental, Health, and Safety Guidelines for Cement and Lime Manufacturing Introduction 1. The Environmental, Health, and Safety (EHS) Guidelines are technical reference documents with general and industry-specific examples of Good International Industry Practice (GIIP).1 When one or more members of the World Bank Group are involved in a project, these EHS Guidelines are applied as required by their respective policies and standards. These industry sector EHS guidelines are designed to be used together with the General EHS Guidelines document, which provides guidance to users on common EHS issues potentially applicable to all industry sectors. For complex projects, use of multiple industry sector guidelines may be necessary. A complete list of industry sector guidelines can be found at www.ifc.org/ehsguidelines. 2. The EHS Guidelines contain the performance levels and measures that are generally considered to be achievable in new facilities by existing technology at reasonable costs. Application of the EHS Guidelines to existing facilities may involve the establishment of site-specific targets, with an appropriate timetable for achieving them. 3. The applicability of the EHS Guidelines should be tailored to the hazards and risks established for each project on the basis of the results of an environmental assessment in which site-specific variables, such as host country context, assimilative capacity of the environment, and other project factors, are taken into account. The applicability of specific technical recommendations should be based on the professional opinion of qualified and experienced persons.
    [Show full text]
  • CBA® Quality/Strength-Enhancing Additive
    PRODUCT DATA SHEET CBA® Quality/strength-enhancing additive Product Description The CBA® series of additives is a new concept in grinding aids - significantly different from any previous GCP product for the cement industry. The difference is that it is a “Grinding Aid Plus”. CBA additives offer all the benefits of traditional grinding aids, such as increased grinding efficiency and cement flowability. In addition, they offer a unique ability to improve cement strengths which might otherwise be deficient due to mechanical, physical or chemical shortcomings. Advantages include either reduced cost of production or increased cement strengths. Physical Properties Product specifications for the most widely used CBA formulations are as follows: Product SG pH CBA 1102 1.06 (±0.01) 7 - 9 CBA 1104 1.07 (±0.01) 8 - 12 CBA 1115 1.10 (±0.01) 6 - 8 Specifications for other CBA formulations not shown above are available through GCP Applied Technologies Field Engineers. • Increased early and long-term compressive strengths for production of better quality cements. Primary Benefit • Reduced cost of cement production through reduced unit grinding The CBA series of additives consists of tailor-made formulations costs and through replacement of clinker with reactive additions to optimise performance and meet specific requirements at each such as pozzolans, blast furnace slag and fly ash or with fillers such plant. as limestone. The use of CBA allows the cement producer to reduce fineness • CBA additives are most effective in enhancing compressive and achieve lower unit power costs without sacrificing strength. strengths of blended cements using up to 40% limestone filler. Compared with conventional grinding aids, CBA offers unit power • When cement particle size is not reduced, the addition of CBA savings of up to 25% with no loss of strength.
    [Show full text]
  • OK™ Cement Mill the Most Energy- Efficient Mill for Cement Grinding
    OK™ cement mill The most energy- efficient mill for cement grinding WE DISCOVER POTENTIAL Quality and profit-improving features Application advantages Design advantages Proven commercially, the OK™ mill is the premier roller mill for The OK mill uses a hydro-pneumatic system to press its grinding finish grinding of Portland cement, slag and blended cements. The rollers against the material bed on the rotating grinding table. mill consistently uses five to ten percent less power than other The patented grooved roller profile has two grinding zones, an cement vertical roller mills, and in comparison with traditional ball inner and an outer. The inner zone prepares the grinding bed by mill operations, the energy requirements for the OK cement mill is compressing the feed material as it moves under the rollers into the 30-45 percent lower for cement grinding and 40-50 percent lower high-pressure grinding zone. The center groove allows air to for slag. The OK mill can contribute significantly to profitability and escape from the material. Grinding pressure is concentrated under competitiveness. the outer zone of the roller, allowing for most efficient operation. Segmented roller wear parts are made of the hardest possible The design combines the drying, grinding, material conveying and material without risk of cracking and are very well suited for hard separation processes into just one unit, thus simplifying the plant facing. Re-positioning of rollers is possible for evening out wear. layout. These features ensure maximum longevity. The OK mill incorporates unique patented design elements in the Operating advantages roller and table profile that improve operating stability and reliability, The rollers are in a lifted position when the mill is started, ensuring giving a typical availability of 90 to 95 percent of scheduled ope- trouble-free start-up.
    [Show full text]
  • Item 421 Hydraulic Cement Concrete
    421 Item 421 Hydraulic Cement Concrete 1. DESCRIPTION Furnish hydraulic cement concrete for concrete pavements, concrete structures, and other concrete construction. 2. MATERIALS Use materials from prequalified sources listed on the Department website. Provide coarse and fine aggregates from sources listed in the Department’s Concrete Rated Source Quality Catalog (CRSQC). Use materials from non-listed sources only when tested and approved by the Engineer before use. Allow 30 calendar days for the Engineer to sample, test, and report results for non-listed sources. Do not combine approved material with unapproved material. 2.1. Cement. Furnish cement conforming to DMS-4600, “Hydraulic Cement.” 2.2. Supplementary Cementing Materials (SCM). Fly Ash. Furnish fly ash, ultra-fine fly ash (UFFA), and modified Class F fly ash (MFFA) conforming to DMS-4610, “Fly Ash.” Slag Cement. Furnish Slag Cement conforming to DMS-4620, “Slag Cement.” Silica Fume. Furnish silica fume conforming to DMS-4630, “Silica Fume.” Metakaolin. Furnish metakaolin conforming to DMS-4635, “Metakaolin.” 2.3. Cementitious Material. Cementitious materials are the cement and supplementary cementing materials used in concrete. 2.4. Chemical Admixtures. Furnish admixtures conforming to DMS-4640, “Chemical Admixtures for Concrete.” 2.5. Water. Furnish mixing and curing water that is free from oils, acids, organic matter, or other deleterious substances. Water from municipal supplies approved by the Texas Department of Health will not require testing. Provide test reports showing compliance with Table 1 before use when using water from other sources. Water that is a blend of concrete wash water and other acceptable water sources, certified by the concrete producer as complying with the requirements of both Table 1 and Table 2, may be used as mix water.
    [Show full text]
  • TDA Cement Additive
    Product Data Sheets TDA ® Quality Improvers A Family of Strength Enhancing Cement Additives Product Description TDA ® Quality Improvers are a family of cement additives that improve the strength or other performance characteristics of cement. They are aqueous compositions of grinding aids with set accelerating, water reducing or strength enhancing compounds, all carefully controlled and accurately blended for constant quality and optimum performance. Product specifications for the most widely used TDA ® formulations are as follows: S.G.S.G. PHPH TDA ® J 1.22 (±0.01) 6 - 8 TDA ® N 1.21 (±0.01) 8 - 10 TDA ® 710 1.34 (±0.02) 8 - 10 TDA ® 770 1.17 (±0.01) 8 - 10 TDA ® 1223 1.15 (±0.05) 6 - 8 TDA ® 7014 1.03 (±0.02) 9 - 12 Product specifications for other TDA ® formulations are available through GCP Field Engineers. Product Advantages One of the key benefits of TDA ® additives is their ability to increase both the grinding efficiency and cement strengths to a degree unequalled by conventional grinding aids. Increased early and long-term compressive strengths for the production of better quality cements. Reduced cost of cement production through reduced unit grinding costs and through replacement of clinker with reactive additions such as pozzolans, blast furnace slag and fly ash, or with fillers such as limestone. The chemical action of TDA ® additives decreases the interparticle attraction between cement grains both in dry form and in water, and increases the rate of hydration of cements. Additional advantages of TDA ® additives include: Page 1 of 5 Product Data Sheets Increased grinding efficiency resulting in increased mill output, higher cement fineness and reduced unit power input and grinding costs.
    [Show full text]
  • The Influence of Triethanol Amine and Ethylene Glycol on the Grindability, Setting and Hydration Characteristics of Portland Cement
    International Journal of Petrochemical Science & Engineering Research Article Open Access The influence of Triethanol amine and ethylene glycol on the grindability, setting and hydration characteristics of Portland cement Abstract Volume 4 Issue 3 - 2019 Triethanol amine and ethylene glycol are used as grinding aids for Ordinary Fayza S Hashem, Eisa E Hekal, M Abd El Portland Cement (OPC). Standard water of consistency, Blaine area, initial and final setting times and compressive strength are tested for OPC. The phase composition Wahab and microstructure of the formed hydrates are tested using DTA/TG and SEM Chemistry Department, Faculty of Science, Ain Shams techniques. Results showed that both the two GAs had a significant improvement in University, Egypt the performance of grinding mills. This is indicating by higher Blaine area when a Correspondence: Fayza S Hashem, Professor, Chemistry dose of 0.03, 0.04 and 0.05wt. % are applied. Beside there are increase in the water Department, Faculty of Science, Ain Shams University, Cairo, demand (greater than 5%) for the all OPC mortar mixes admixed with triethanol amin Egypt, Tel +0020111784595, Email or ethylene glycol at concentrations less than 0.05 wt.%. The improved hydration properties are reflected by an increase in the mechanical properties and microstructure Received: January 24, 2019 | Published: May 02, 2019 of the mortar pastes admixed with the two GAs. This is with attributed to the increase in the cement fineness which leads to the progress in the degree of cement hydration. Keywords: portland cement, triethanol amine, ethylene glycol, water demand, setting time and compressive strength Introduction However its action on cement pastes is very complex and depending on the type of cement and the amount of TEA.1,13‒15 An addition of Grinding aids are mostly organic compounds that are added to 0.02 % of TEA to Portland cement, acts as a set accelerator at 0.25 the clinker in the cement mill.
    [Show full text]
  • Calcium Sulphoaluminate Cement with Mayenite Phase
    (19) TZZ¥_ZZ_T (11) EP 3 199 500 A1 (12) EUROPEAN PATENT APPLICATION (43) Date of publication: (51) Int Cl.: 02.08.2017 Bulletin 2017/31 C04B 7/32 (2006.01) (21) Application number: 17153241.9 (22) Date of filing: 26.01.2017 (84) Designated Contracting States: (72) Inventors: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB • SUCU, MEL KE GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO MERS N (TR) PL PT RO RS SE SI SK SM TR • DEL BA , TU HAN Designated Extension States: MERS N (TR) BA ME Designated Validation States: (74) Representative: Dereligil, Ersin MA MD Destek Patent Inc. Lefkose Cad. NM Ofis Park (30) Priority: 29.01.2016 TR 201601267 B Blok No: 36/5 Besevler Nilüfer 16110 Bursa (TR) (71) Applicant: CIMSA CIMENTO SANAYI VE TICARET ANONIM SIRKETI Mersin (TR) (54) CALCIUM SULPHOALUMINATE CEMENT WITH MAYENITE PHASE (57) The invention is calcium sulphoaluminate ce- waste during aluminium production; soda waste as pulp ment having a dicalcium silicate (C 2S), calcium sulphoa- obtained in soda production facilities remaining after so- luminate - yeelimite (C 4A3S), tetracalcium iron aluminate da ash is removed as product; fly ash obtained from stack (C4AF), calcium sulphate (CS) and mayenite (C12A7) gases as a result of the combustion of pulverized coal in mineral phase structure, and comprises gypsum or phos- thermal power plants; waste bauxite obtained in calcium phogypsum; dross aluminium which is produced as aluminate cement production facilities. EP 3 199 500 A1 Printed by Jouve, 75001 PARIS (FR) EP 3 199 500 A1 Description Technical Field 5 [0001] The present invention relates to cements used in the construction sector.
    [Show full text]
  • Use of Recycled Aggregates for Cement Production
    21 January 2021 SeRaMCo Digital final conference Use of recycled aggregates for cement production André LECOMTE Laury BARNES-DAVIN Cécile DILIBERTO Amor BEN-FRAJ Breffni BOLZE Romain TRAUCHESSEC Nacef TAZI Arnaud DELHAY Hichem KROUR Outline Introduction I. Laboratory experiments II. Industrial production III. Durability Conclusion 2 Introduction Clinker Natural materials Cement raw meal (CRM) Recycled aggregates Firing 3 Introduction SiO 2 Max incorporation rate 10-12% Varies widely (10 à 94)% Recycled aggregates incorporation 12-15% rate1,2 10% 15-20% Impacted by the Silicium-Calcium couple 20-30% 30-50% >50% Depends also on: Cement raw meal • Type of cement plant quarries 94% • Chemical composition of natural materials CaO + Al2O3 + MgO Fe2O3 • Type of clinker/cement produced 10% of calculations ► < 5% Incorporation rate of at least 5% is possible for 73% of calculations ► 10 to 30% 17% of calculations ► > 30% 90% of calculations 1. H. Krour et al, (2020) «Incorporation rate of recycled aggregates in cement raw meals » Construction and Building Materials. 4 2. H. Krour, (2020) «Incorporation des déchets de construction et de démolition dans le cru cimentier » PhD Thesis (in French). I. Laboratory experiments Laboratory synthesis of cement raw meals (CRM) Ref GM1-N CT 40 Compared to reference CRM 30 Reduced burnability (EDTA, %) (EDTA, 20 40 Highest free lime 37 36 35 34 32 Changes on intermediate 31 31 content 28 contenct 10 19 20 21 phases 0 100 Free lime lime Free 1000 °C 1050 °C 1100 °C 1200 °C Ref 60 80 ) GM1-N u.a CT 50 60 40 40 Alum. Fer. (Rietveld, %) (Rietveld, Lower belite ( Intensity Geh.
    [Show full text]
  • Sustainable Production of Blended Cement in Pakistan Through Addition of Natural Pozzolana
    Available on line at Association of the Chemical Engineers of Serbia AChE Chemical Industry & Chemical Engineering Quarterly www.ache.org.rs/CICEQ Chem. Ind. Chem. Eng. Q. 22 (1) 41−45 (2016) CI&CEQ MUHAMMAD IMRAN AHMAD1 SUSTAINABLE PRODUCTION OF BLENDED MUHAMMAD SAJJAD1 2 CEMENT IN PAKISTAN THROUGH ADDITION IRFAN AHMED KHAN OF NATURAL POZZOLANA AMINA DURRANI2 1 ALI AHMED DURRANI Article Highlights 1 SAEED GUL • Ordinary Portland cement is partially substituted with rhyolite to reduce cost ASMAT ULLAH1 • Blended cements employing rhyolite are demonstrated to possess satisfactory com- pressive strength 1 Department of Chemical • Inter-grinding of rhyolite and clinker to produce blended cement shows reduced Engineering, University of energy consumption Engineering and Technology, Peshawar, Pakistan Abstract 2Qadir Enterprises, Peshawar, In this work, pozzolana deposits of district Swabi, Pakistan were investigated Pakistan for partial substitution of Portland cement along with limestone filler. The cem- ent samples were mixed in different proportions and tested for compressive SCIENTIFIC PAPER strength at 7 and 28 days. The strength activity index (SAI) for 10% pozzolana, UDC 666.94(549.1) and 5% limestone blend at 7 and 28 days was 75.5 and 85.0% satisfying the minimum SAI limit of ASTM C618. 22% natural pozzolana and 5% limestone DOI 10.2298/CICEQ141012017A were interground with clinker and gypsum in a laboratory ball mill to compare the power consumption with ordinary Portland cement (OPC) (95% clinker and 5% gypsum). The ternary blended cement took less time to reach the same fineness level as OPC due to soft pozzolana and high grade lime stone, indi- cating that intergrinding may reduce overall power consumption.
    [Show full text]
  • Report on the Performance of Portland Limestone Cements in Concrete 20160401
    PERFORMANCES OF LIMESTONE MODIFIED PORTLAND CEMENT AND CONCRETE Luc Courard, University of Liège, Belgium Duncan Herfort, Aalborg Portland A/S, Denmark Yury Villagrán, LEMIT and CONICET, Argentina Corresponding author: Luc Courard – University of Liège, Department of Architecture, Geology, Environment and Constructions, Allée de la Découverte, 9 (Quartier Polytech) – 4000 LIEGE (Belgium), Email: [email protected] 1. Introduction Fine limestone has been added to Portland cement for decades. This is normally achieved by “intergrinding” it with Portland cement clinker in the cement mill. Under normal operating conditions this will result in a surface area of the limestone fraction of between 800 and 1100 m 2/kg (depending on the grindability of the limestone) for a surface area of the clinker fraction of in the region of 400 m 2/kg. Less often the limestone is ground separately and blended with Portland cement. Separate addition of limestone to concrete as a clinker replacement is not widely practiced in conventional concrete, but is used as filler for modifying the rheology of self-compacting concrete. In the early literature limestone was generally regarded as “inert filler”. For this reason it has e.g. become the main constituent in most masonry cements where high levels of replacement of the Portland cement are needed to reproduce the properties of traditional lime mortars. However, for its application in concrete, which is the primary focus of this report, the limestone’s contribution to the hydration reactions can be significant when it is co-ground with the clinker, albeit in relatively small amounts. So much so that it can arguably be classified as an SCM alongside GBFS and fly ash.
    [Show full text]
  • Background Facts and Issues Concerning Cement and Cement Data
    Background Facts and Issues Concerning Cement and Cement Data By Hendrik G. van Oss Open-File Report 2005-1152 U.S. Department of the Interior U.S. Geological Survey ii U.S. Department of the Interior Gale A. Norton, Secretary U.S. Geological Survey P. Patrick Leahy, Acting Director For product and ordering information: World Wide Web: http://www.usgs.gov/pubprod Telephone: 1-888-ASK-USGS For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment: World Wide Web: http://www.usgs.gov Telephone: 1-888-ASK-USGS Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted material contained within this report. iii Preface This report is divided into two main parts. Part 1 first serves as a general overview or primer on hydraulic (chiefly portland) cement and, to some degree, concrete. Part 2 describes the monthly and annual U.S. Geological Survey (USGS) cement industry canvasses in general terms of their coverage and some of the issues regarding the collection and interpretation of the data therein. The report provides background detail that has not been possible to include in the USGS annual and monthly reports on cement. These periodic publications, however, should be referred to for detailed current data on U.S. production and sales of cement. It is anticipated that the contents of this report may be updated and/or supplemented from time to time.
    [Show full text]
  • Fly Ash As a Soil Amendment in the Northern Red River Valley Amy Decker
    University of North Dakota UND Scholarly Commons Undergraduate Theses and Senior Projects Theses, Dissertations, and Senior Projects 2005 Fly Ash as a Soil Amendment in the Northern Red River Valley Amy Decker Follow this and additional works at: https://commons.und.edu/senior-projects Recommended Citation Decker, Amy, "Fly Ash as a Soil Amendment in the Northern Red River Valley" (2005). Undergraduate Theses and Senior Projects. 86. https://commons.und.edu/senior-projects/86 This Senior Project is brought to you for free and open access by the Theses, Dissertations, and Senior Projects at UND Scholarly Commons. It has been accepted for inclusion in Undergraduate Theses and Senior Projects by an authorized administrator of UND Scholarly Commons. For more information, please contact [email protected]. GEOL . UT2005 • 02952 Decker, Amy SHELVE BY AUTHOR WITH THESES AND DISSERTATIONS! FLY ASH AS A SOIL AMENDMENT IN THE NORTHERN RED RNER VALLEY • A Senior Design Presented to The Department of Geological Engineering In Partial Fulfillment of the Requirements for the Degree Bachelor of Science in Geological Engineering • By Arny Decker May li\ 2005 • EXECUTIVE SUMMARY Combustion of coal occurs worldwide to produce energy for nwnerous residential and industrial processes. During coal combustion, byproducts including fly ash, bottom ash and slag are formed (Lafarge, 2004). By standard regulations, power plants in the United States and many other countries must effectively capture and dispose of these byproducts. Over 118 million tons of combustion byproducts are produced and captured • each year in the United States alone. Disposal of this extraordinary amount of waste is difficult and costly.
    [Show full text]