Strength and Microstructures of Hardened Cement Pastes Cured by Autoclaving S
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Crystal Structure of Hillebrandite: a Natural Analogue of Calcium Silicate Hydrate (CSH) Phases in Portland Cement
American Mineralogist, Volume 80, pages 841-844, 1995 Crystal structure of hillebrandite: A natural analogue of calcium silicate hydrate (CSH) phases in Portland cement YONGSHAN DAI Garber Research Center, Harbison-Walker Refractories, 1001 Pittsburgh-McKeesport Boulevard, West Miffilin, Pennsylvania 15122, U.S.A. JEFFREY E. POST Departmentof MineralSciences,SmithsonianInstitution,Washington,DC 20560,U.S.A. ABSTRACT The crystal structure of hillebrandite, Ca2Si03(OH)2, was solved and refined in space group Cmc21, a = 3.6389, b = 16.311, c = 11.829 A, to R = 0.041 using single-crystal X-ray data. The structure consists of a three-dimensional network of Ca-O polyhedra that accommodates wollastonite-type Si-O tetrahedral chains. Each of the wollastonite-type chains is an average of two symmetrically equivalent chains related by the mirror plane perpen- dicular to a. In a given structural channel of the Ca-O polyhedral network, only one chain orientation can be occupied to give reasonable Si-O distances. The 03 and 04 sites cor- responding to each vacant Si2 site are occupied by OH groups to achieve charge balance. The wollastonite-type Si-O tetrahedral chains in the hillebrandite structure resemble those reported for many calcium silicate hydrate (CSH) phases. INTRODUCTION brandite and comment upon the structural relationships Hillebrandite, Ca2Si03(OH)2, is one natural member of hillebrandite with other CSH phases. of the CaO-Si02-H20 ternary system, which includes nu- merous natural and synthetic calcium silicate hydrate EXPERIMENTAL METHODS (CSH) phases, most with a common unit-cell axis of about After an exhaustive examination of many hillebrandite 3.64 or 2 x 3.64 A and a fibrous crystal habit along this samples, a fragment ofa specimen (NMNH 95767-7) from axis. -
Cement/Clay Interactions - a Review: Experiments, Natural Analogues, and Modeling Eric C
Cement/clay interactions - A review: Experiments, natural analogues, and modeling Eric C. Gaucher, Philippe Blanc To cite this version: Eric C. Gaucher, Philippe Blanc. Cement/clay interactions - A review: Experiments, natural analogues, and modeling. Waste Management, Elsevier, 2006, 26, pp.776-788. 10.1016/j.wasman.2006.01.027. hal-00664858 HAL Id: hal-00664858 https://hal-brgm.archives-ouvertes.fr/hal-00664858 Submitted on 31 Jan 2012 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. CEMENT/CLAY INTERACTIONS – A REVIEW: EXPERIMENTS, NATURAL ANALOGUES, AND MODELING. Eric C. Gaucher*, Philippe Blanc BRGM, 3 avenue C. Guillemin, BP 6009, 45100 Orleans Cedex, France * Corresponding author. [email protected] Tel: 33.2.38.64.35.73 Fax: 33.2.38.64.30.62 1 Abstract The concept of storing radioactive waste in geological formations calls for large quantities of concrete that will be in contact with the clay material of the engineered barriers as well as with the geological formation. France, Switzerland and Belgium are studying the option of clayey geological formations. The clay and cement media have very contrasted chemistries that will interact and lead to a degradation of both types of material. -
Apophyllite-(Kf)
December 2013 Mineral of the Month APOPHYLLITE-(KF) Apophyllite-(KF) is a complex mineral with the unusual tendency to “leaf apart” when heated. It is a favorite among collectors because of its extraordinary transparency, bright luster, well- developed crystal habits, and occurrence in composite specimens with various zeolite minerals. OVERVIEW PHYSICAL PROPERTIES Chemistry: KCa4Si8O20(F,OH)·8H20 Basic Hydrous Potassium Calcium Fluorosilicate (Basic Potassium Calcium Silicate Fluoride Hydrate), often containing some sodium and trace amounts of iron and nickel. Class: Silicates Subclass: Phyllosilicates (Sheet Silicates) Group: Apophyllite Crystal System: Tetragonal Crystal Habits: Usually well-formed, cube-like or tabular crystals with rectangular, longitudinally striated prisms, square cross sections, and steep, diamond-shaped, pyramidal termination faces; pseudo-cubic prisms usually have flat terminations with beveled, distinctly triangular corners; also granular, lamellar, and compact. Color: Usually colorless or white; sometimes pale shades of green; occasionally pale shades of yellow, red, blue, or violet. Luster: Vitreous to pearly on crystal faces, pearly on cleavage surfaces with occasional iridescence. Transparency: Transparent to translucent Streak: White Cleavage: Perfect in one direction Fracture: Uneven, brittle. Hardness: 4.5-5.0 Specific Gravity: 2.3-2.4 Luminescence: Often fluoresces pale yellow-green. Refractive Index: 1.535-1.537 Distinctive Features and Tests: Pseudo-cubic crystals with pearly luster on cleavage surfaces; longitudinal striations; and occurrence as a secondary mineral in association with various zeolite minerals. Laboratory analysis is necessary to differentiate apophyllite-(KF) from closely-related apophyllite-(KOH). Can be confused with such zeolite minerals as stilbite-Ca [hydrous calcium sodium potassium aluminum silicate, Ca0.5,K,Na)9(Al9Si27O72)·28H2O], which forms tabular, wheat-sheaf-like, monoclinic crystals. -
Raman Spectroscopy and Single-Crystal High-Temperature Investigations of Bentorite, Ca6cr2(SO4)3(OH)12·26H2O
minerals Article Raman Spectroscopy and Single-Crystal High-Temperature Investigations of Bentorite, Ca6Cr2(SO4)3(OH)12·26H2O Rafał Juroszek 1,* , Biljana Krüger 2 , Irina Galuskina 1 , Hannes Krüger 2 , Martina Tribus 2 and Christian Kürsten 2 1 Institute of Earth Sciences, Faculty of Natural Sciences, University of Silesia, B˛edzi´nska60, 41-205 Sosnowiec, Poland; [email protected] 2 Institute of Mineralogy and Petrography, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria; [email protected] (B.K.); [email protected] (H.K.); [email protected] (M.T.); [email protected] (C.K.) * Correspondence: [email protected]; Tel.: +48-516-491-438 Received: 28 November 2019; Accepted: 27 December 2019; Published: 30 December 2019 Abstract: The crystal structure of bentorite, ideally Ca Cr (SO ) (OH) 26H O, a Cr3+ analogue of 6 2 4 3 12· 2 ettringite, is for the first time investigated using X-ray single crystal diffraction. Bentorite crystals of suitable quality were found in the Arad Stone Quarry within the pyrometamorphic rock of the Hatrurim Complex (Mottled Zone). The preliminary semi-quantitative data on the bentorite composition obtained by SEM-EDS show that the average Cr/(Cr + Al) ratio of this sample is >0.8. Bentorite crystallizes in space group P31c, with a = b = 11.1927(5) Å, c =21.7121(10) Å, V = 2355.60(18) Å3, and Z = 2. The crystal structure is refined, including the hydrogen atom positions, to an agreement index R1 = 3.88%. The bentorite crystal chemical formula is Ca (Cr Al ) [(SO ) (CO ) ] (OH) ~25.75H O. -
Carbonation of Borehole Seals: Comparing Evidence from Short-Term Laboratory Experiments and Long-Term Natural Analogues Christopher A
Carbonation of borehole seals: Comparing evidence from short-term laboratory experiments and long-term natural analogues Christopher A. Rochelle* and Antoni E. Milodowski British Geological Survey, Environmental Science Centre, Nicker Hill, Keyworth, Nottingham, NG12 5GG, UK * Corresponding author: [email protected], tel +44 115 9363259, fax +44 115 363200 Abstract It is crucial that the engineered seals of boreholes in the vicinity of a deep storage facility remain effective for considerable timescales if the long-term geological containment of stored CO2 is to be effective. These timescales extend beyond those achievable by laboratory experiments or industrial experience. Study of the carbonation of natural Ca silicate hydrate (CSH) phases provides a useful insight into the alteration processes and evolution of cement phases over long-timescales more comparable with those considered in performance assessments. Samples from two such natural analogues in Northern Ireland have been compared with samples from laboratory experiments on the carbonation of Portland cement. Samples showed similar carbonation reaction processes even though the natural and experimental samples underwent carbonation under very different conditions and timescales. These included conversion of the CSH phases to CaCO3 and SiO2, and the formation of a well-defined reaction front. In laboratory experiments the reaction front is associated with localised Ca migration, localised matrix porosity increase, and localised shrinkage of the cement matrix with concomitant cracking. Behind the reaction front is a zone of CaCO3 precipitation that partly seals porosity. A broader and more porous/permeable reaction zone was created in the laboratory experiments compared to the natural samples, and it is possible that short-term experiments might not fully replicate slower, longer-term processes. -
Mayenite Ca12al14o33 C 2001-2005 Mineral Data Publishing, Version 1
Mayenite Ca12Al14O33 c 2001-2005 Mineral Data Publishing, version 1 Crystal Data: Cubic. Point Group: 43m (synthetic). In rounded anhedral grains, to 60 µm. Physical Properties: Hardness = n.d. D(meas.) = 2.85 D(calc.) = [2.67] Alters immediately to hydrated calcium aluminates on exposure to H2O. Optical Properties: Transparent. Color: Colorless. Optical Class: Isotropic. n = 1.614–1.643 Cell Data: Space Group: I43d (synthetic). a = 11.97–12.02 Z = 2 X-ray Powder Pattern: Near Mayen, Germany. 2.69 (vs), 4.91 (s), 2.45 (ms), 3.00 (m), 2.19 (m), 1.95 (m), 1.66 (m) Chemistry: (1) (2) (3) SiO2 0.4 Al2O3 45.2 49.5 51.47 Fe2O3 2.0 1.5 MnO 1.4 CaO 45.7 47.0 48.53 LOI 2.2 Total 95.1 99.8 100.00 (1) Near Mayen, Germany; by semiquantitative spectroscopy. (2) Hatrurim Formation, Israel; by electron microprobe, corresponding to (Ca11.7Mg0.5)Σ=12.2(Al13.5Fe0.25Si0.10)Σ=13.85O33. (3) Ca12Al14O33. Occurrence: In thermally metamorphosed limestone blocks included in volcanic rocks (near Mayen, Germany); common in high-temperature, thermally metamorphosed, impure limestones (Hatrurim Formation, Israel). Association: Calcite, ettringite, wollastonite, larnite, brownmillerite, gehlenite, diopside, pyrrhotite, grossular, spinel, afwillite, jennite, portlandite, jasmundite (near Mayen, Germany); melilite, wollastonite, kalsilite, brownmillerite, corundum (Kl¨och, Austria); spurrite, larnite, grossite, brownmillerite (Hatrurim Formation, Israel). Distribution: From the Ettringer-Bellerberg volcano, near Mayen, Eifel district, Germany. Found at Kl¨och, Styria, Austria. In the Hatrurim Formation, Israel. From Kopeysk, Chelyabinsk coal basin, Southern Ural Mountains, Russia. Name: For Mayen, Germany, near where the mineral was first described. -
Calcium-Aluminum-Silicate-Hydrate “
Cent. Eur. J. Geosci. • 2(2) • 2010 • 175-187 DOI: 10.2478/v10085-010-0007-6 Central European Journal of Geosciences Calcium-aluminum-silicate-hydrate “cement” phases and rare Ca-zeolite association at Colle Fabbri, Central Italy Research Article F. Stoppa1∗, F. Scordari2,E.Mesto2, V.V. Sharygin3, G. Bortolozzi4 1 Dipartimento di Scienze della Terra, Università G. d’Annunzio, Chieti, Italy 2 Dipartimento Geomineralogico, Università di Bari, Bari, Italy 3 Sobolev V.S. Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia 4 Via Dogali, 20, 31100-Treviso Received 26 January 2010; accepted 8 April 2010 Abstract: Very high temperature, Ca-rich alkaline magma intruded an argillite formation at Colle Fabbri, Central Italy, producing cordierite-tridymite metamorphism in the country rocks. An intense Ba-rich sulphate-carbonate- alkaline hydrothermal plume produced a zone of mineralization several meters thick around the igneous body. Reaction of hydrothermal fluids with country rocks formed calcium-silicate-hydrate (CSH), i.e., tobermorite- afwillite-jennite; calcium-aluminum-silicate-hydrate (CASH) – “cement” phases – i.e., thaumasite, strätlingite and an ettringite-like phase and several different species of zeolites: chabazite-Ca, willhendersonite, gismon- dine, three phases bearing Ca with the same or perhaps lower symmetry of phillipsite-Ca, levyne-Ca and the Ca-rich analogue of merlinoite. In addition, apophyllite-(KF) and/or apophyllite-(KOH), Ca-Ba-carbonates, portlandite and sulphates were present. A new polymorph from the pyrrhotite group, containing three layers of sphalerite-type structure in the unit cell, is reported for the first time. Such a complex association is unique. -
Zeolites in Tasmania
Mineral Resources Tasmania Tasmanian Geological Survey Record 1997/07 Tasmania Zeolites in Tasmania by R. S. Bottrill and J. L. Everard CONTENTS INTRODUCTION ……………………………………………………………………… 2 USES …………………………………………………………………………………… 2 ECONOMIC SIGNIFICANCE …………………………………………………………… 2 GEOLOGICAL OCCURRENCES ………………………………………………………… 2 TASMANIAN OCCURRENCES ………………………………………………………… 4 Devonian ………………………………………………………………………… 4 Permo-Triassic …………………………………………………………………… 4 Jurassic …………………………………………………………………………… 4 Cretaceous ………………………………………………………………………… 5 Tertiary …………………………………………………………………………… 5 EXPLORATION FOR ZEOLITES IN TASMANIA ………………………………………… 6 RESOURCE POTENTIAL ……………………………………………………………… 6 MINERAL OCCURRENCES …………………………………………………………… 7 Analcime (Analcite) NaAlSi2O6.H2O ……………………………………………… 7 Chabazite (Ca,Na2,K2)Al2Si4O12.6H2O …………………………………………… 7 Clinoptilolite (Ca,Na2,K2)2-3Al5Si13O36.12H2O ……………………………………… 7 Gismondine Ca2Al4Si4O16.9H2O …………………………………………………… 7 Gmelinite (Na2Ca)Al2Si4O12.6H2O7 ……………………………………………… 7 Gonnardite Na2CaAl5Si5O20.6H2O ………………………………………………… 10 Herschelite (Na,Ca,K)Al2Si4O12.6H2O……………………………………………… 10 Heulandite (Ca,Na2,K2)2-3Al5Si13O36.12H2O ……………………………………… 10 Laumontite CaAl2Si4O12.4H2O …………………………………………………… 10 Levyne (Ca2.5,Na)Al6Si12O36.6H2O ………………………………………………… 10 Mesolite Na2Ca2(Al6Si9O30).8H2O ………………………………………………… 10 Mordenite K2.8Na1.5Ca2(Al9Si39O96).29H2O ………………………………………… 10 Natrolite Na2(Al2Si3O10).2H2O …………………………………………………… 10 Phillipsite (Ca,Na,K)3Al3Si5O16.6H2O ……………………………………………… 11 Scolecite CaAl2Si3O10.3H20 ……………………………………………………… -
Tobermorite and Tobermorite-Like Calcium Silicate Hydrates: Their
TOBERMORITE AND TOBERMORITE-L/KE CALCIUM SILICATE HYDRATES: \ THEIR PROPERTIES AND RELATIONSHIPS TO CLAY MINERALS AUG. 1963 NO. 24 DIAMOND PURDUE UNIVERSITY LAFAYETTE INDIANA Final Report TOBERMDRITE AND TOBERMORITE-LIKE CALCIUM SILICATE HYDRATES: THEIR PROPERTIES AND RELATIONSHIPS TO CIAY MINERALS TO: K. B. Woods, Director Joint Highway Research Project August 2, 1963 PROM: H. L. Michael, Associate Director File: 4-6-9 Joint High-way Research Project Project: C=36-^7I Attached is a Final Report "by Mr. Sidney Diamond, Graduate Assistant on our staff, entitled "Tobermorite and Tobermorite-Like Calcium Silicate Hydrates: Their Properties and Relationships to Clay Minerals"., This research has been performed under the direction of Professors J. L. White of the Purdue University Agronomy Department and Professor W. L. Dolch of our staff. Mr. Diamond also used the report as his disertation for the Ph.D. Degree. The Plan of Study for this research was approved by the Board on May 22, 1962, and it subsequently was approved by the Indiana State Highway Commission and the Bureau of Public Roads as an HPS research project. This is the final report on this project and it will be submitted to the sponsoring organization for review. Several papers from the research are anticipated and each will be submitted to the Board and the sponsors for review and approval prior to publication. The report is submitted to the Board for information and for the record. Respectfully submitted, Harold L. Michael, Secretary HLM:bc Attachment Copies: F. L. Ashbaucher J. F. McLaughlin J. R. Cooper R. D. Miles W. L. -
Formation of Gyrolite in the Cao–Quartz–Na2o–H2O System
Materials Science-Poland, Vol. 25, No. 4, 2007 Formation of gyrolite in the CaO–quartz–Na2O–H2O system K. BALTAKYS*, R. SIAUCIUNAS Department of Silicate Technology, Kaunas University of Technology, Radvilenu 19, LT – 50270 Kaunas, Lithuania Optimizing the duration and/or the temperature of hydrothermal synthesis of gyrolite has been inves- tigated by adding NaOH solution into an initial mixture of CaO–quartz–H2O. The molar ratio of the primary mixture was C/S = 0.66 (C – CaO; S – SiO2). An amount of NaOH, corresponding to 5 % Na2O from the mass of dry materials, added in the form of solution and additional water was used so that the water/solid ratio of the suspension was equal to 10.0. Hydrothermal synthesis of the unstirred suspension was carried out in saturated steam at 150, 175, 200 ºC. The duration of isothermal curing was 4, 8, 16, 24, 32, 48, 72 and 168 h. The temperature of 150 ºC is too low for the synthesis of gyrolite; the stoichiometric ratio C/S = 0.66 is not reached even after 168 h of synthesis neither in pure mixtures nor in mixtures with + addition of Na2O. Na ions significantly influence the formation of gyrolite from the CaO–quartz mix- tures in the temperature range from 175 ºC to 200 ºC. Gyrolite is formed at 175 ºC after 168 h and at 200 ºC after 16 h of isothermal curing. On the contrary, in pure mixtures it does not form even after 72 h at 200 ºC. Na+ ions also change the compositions of intermediate and final products of the synthesis. -
A Specific Gravity Index for Minerats
A SPECIFICGRAVITY INDEX FOR MINERATS c. A. MURSKyI ern R. M. THOMPSON, Un'fuersityof Bri.ti,sh Col,umb,in,Voncouver, Canad,a This work was undertaken in order to provide a practical, and as far as possible,a complete list of specific gravities of minerals. An accurate speciflc cravity determination can usually be made quickly and this information when combined with other physical properties commonly leads to rapid mineral identification. Early complete but now outdated specific gravity lists are those of Miers given in his mineralogy textbook (1902),and Spencer(M,i,n. Mag.,2!, pp. 382-865,I}ZZ). A more recent list by Hurlbut (Dana's Manuatr of M,i,neral,ogy,LgE2) is incomplete and others are limited to rock forming minerals,Trdger (Tabel,l,enntr-optischen Best'i,mmungd,er geste,i,nsb.ildend,en M,ineral,e, 1952) and Morey (Encycto- ped,iaof Cherni,cal,Technol,ogy, Vol. 12, 19b4). In his mineral identification tables, smith (rd,entifi,cati,onand. qual,itatioe cherai,cal,anal,ys'i,s of mineral,s,second edition, New york, 19bB) groups minerals on the basis of specificgravity but in each of the twelve groups the minerals are listed in order of decreasinghardness. The present work should not be regarded as an index of all known minerals as the specificgravities of many minerals are unknown or known only approximately and are omitted from the current list. The list, in order of increasing specific gravity, includes all minerals without regard to other physical properties or to chemical composition. The designation I or II after the name indicates that the mineral falls in the classesof minerals describedin Dana Systemof M'ineralogyEdition 7, volume I (Native elements, sulphides, oxides, etc.) or II (Halides, carbonates, etc.) (L944 and 1951). -
Gyrolite: Its Crystal Structure and Crystal Chemistry
Gyrolite: its crystal structure and crystal chemistry STEFANO MERLINO Dipartimento di Scienze delia Terra, Universita di Pisa, Via S. Maria 53, 56100 Pisa, Italy Abstract The crystal structure of gyrolite from Qarusait, Greenland, was solved and refined with the space group pI and cell parameters a = 9.74(1), b = 9.74(1), c = 22.40(2) A, ex= 95.7(1t, fJ = 91.5(lt, y = l20.0(lt. The structure is built up by the stacking of the structural units already found in the crystal structure ofreyerite (Merlino, 1972, 1988), namely tetrahedral sheets Sl and Sz and octahedral sheets O. The tetrahedral and octahedral sheets are connected by corner sharing to give rise to the complex layer which can be schematically described as S20S10S2, where S2 and as well as a and 0, are symmetry-related units. S2' 5 Successive complex layers with composition [Ca14Si23Al06o(OH)s]- are connected through an interlayer sheet made up by calcium and sodium cations and water molecules. The unit cell content NaCa16Si23Al06o(OHjg' 14H20, determined by the structural study, was confirmed by a chemical analysis, apart from the indication of a somewhat larger water content. The crystal chemistry of gyrolite is discussed on the basis of the present structural results and the chemical data given in the literature for gyrolite from different localities: the crystal chemical formula which accounts for most gyrolite samples is Ca16Si2406o(OHjg '(14+x)H20, with 0 ~ x ~ 3. Stacking disorder, twinning and polytypic variants in gyrolite, as well as the structural relationships of gyrolite with truscottite, reyerite, fedorite and the synthetic phases K and Z are described and discussed.