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Showing papers on "Silica fume published in 2001"


Book
29 Dec 2001
TL;DR: The use of Synchroton sources in the study of Cement Materials as discussed by the authors has been shown to be useful in the analysis of Cements and their applications in many applications.
Abstract: 1. Cement Manufacture 2. Composition of Cement Phases 3. The Hydration of Portland Cement 4. Calcium Aluminate Cements 5. Properties of Concrete with Mineral and Chemical Admixtures 6. Special Cements 7. Developments with Oilwell Cements 8. Gypsum in Cements 9. Alkali-Silica Reaction in Concrete 10. Delayed Ettringite Formation 11. Chloride-Corrosion in Cementitious Systems 12. Blastfurnace Cements 13. Properties and Applications of Natural Pozzolanas 14. Pulverised Fuel Ash as a Cement Extender 15. Metakaolin as a Pollolanic Addition to Concrete 16. Condensed Silica Fume as a Cement Extender 17. Cement-Based Composite Micro-Structures 18. X-Ray Powder Diffraction Analysis of Cements 19. Electron Microscopy of Cements 20. Electrical Monitoring Methods in Cement Science 21. Nuclear Magnetic Resonance Spectroscopy and Magnetic Resonance Imaging Studies of Cements and Cement-Based Materials 22. The Use of Synchroton Sources in the Study of Cement Materials

637 citations


Journal ArticleDOI
TL;DR: In this paper, the strength and durability performance of normal and high-strength pozzolanic concretes incorporating silica fume, fly ash, and blast furnace slag was compared at elevated temperatures up to 800°C.

384 citations


Journal ArticleDOI
TL;DR: In this paper, the hydration progress in metakaolin-blended high-performance cement pastes with age was assessed from the measurements of compressive strength, porosity, and pore size distribution, the degree of pozzolanic reaction, and the Ca(OH)2(CH) content of the MK-blending pastes at a water-to-binder ratio of 0.3.

366 citations


Journal ArticleDOI
TL;DR: In this paper, the effects of ultrafine ground granulated blast-furnace slag (GGBS) and silica fume (SF) on creep and drying shrinkage of HPC were compared and the mechanism was analyzed.

233 citations


Journal ArticleDOI
TL;DR: In this article, the effects of elevated temperature exposure on residual mechanical properties of HPC cylinders were measured by heating the 102×204 mm cylinders to steady state thermal conditions at a target temperature, and loading them to failure after the specimens had cooled to room temperature.
Abstract: This paper describes results of NIST's experimental program that focuses on effects of elevated temperature exposure on residual mechanical properties of HPC. Residual mechanical properties were measured by heating the 102×204 mm cylinders to steady state thermal conditions at a target temperature, and loading them to failure after the specimens had cooled to room temperature. The test specimens were made of four HPC mixtures with water-to-cementitious material ratio (w/cm) ranging from 0.22 to 0.57, and room-temperature compressive strength at testing ranges from 51 MPa to 93 MPa. Two of the four HPC mixtures contained silica fume. The specimens were heated to a maximum core temperature of 450°C, at a heating rate of 5°C/min. Experimental results indicate that HPCs with higher original strength (lowerw/cm) and with silica fume retain more residual strength after elevated temperature exposure than those with lower original strength (higherw/cm) and without silica fume. The differences in modulus of elasticity are less significant. However, the potential for explosive spalling increased in HPC specimens with lowerw/cm and silica fume. An examination of the specimens' heating characteristics indicate that the HPC mixtures which experienced explosive spalling had a more restrictive process of capillary pore and chemically bound water loss than those which did not experience spalling.

224 citations


Journal ArticleDOI
TL;DR: In this paper, the effects of aggressive chemical environments were evaluated on the mortars prepared with ordinary portland cement (OPC) and silica fume (SF)/metakaolin (MK)/low-calcium fly ash at various replacement levels.

216 citations


Journal ArticleDOI
TL;DR: In this article, a new segregation-controlled design methodology for self-compacting concrete (SCC) is introduced, which suggests that aggregate segregation is governed by the yield stress, viscosity, and density of the cement paste matrix.
Abstract: This paper introduces a new segregation-controlled design methodology for self-compacting concrete (SCC). The theory suggests that aggregate segregation is governed by the yield stress, viscosity, and density of the cement paste matrix. The concept of a rheological self-flow zone for concrete is also introduced, where aggregate segregation is avoided, yet the concrete has a high workability. The applicability of the theory is studied by systematically changing the rheology of the cement paste matrix of fresh concrete. The yield stress and viscosity of 3 different types of pastes incorporating silica fume and a cellulose thickening agent are measured as a function of density. Results suggest that the new segregation control design theory can be used to produce SCC.

199 citations


Journal ArticleDOI
TL;DR: In this article, the compressive strength of concretes made up of mixtures of expanded perlite (EPA) and pumice aggregates (PA) was investigated, and the effects of silica fume (SF) and class C fly ash (FA) were determined.

169 citations


Journal ArticleDOI
TL;DR: In this paper, the influence of two mineral admixtures, silica fume (SF) and high-reactivity metakaolin (HRM), on the chemistry of alkali-silica reaction (ASR) products was investigated.
Abstract: This investigation studies the influence of two mineral admixtures, silica fume (SF) and high-reactivity metakaolin (HRM), on the chemistry of alkali–silica reaction (ASR) products Four different mortar bar mixes containing different combinations of high-alkali cement, alkali–inert dolomitic limestone, reactive Beltane opal, HRM, and SF were prepared and stored in a 1 N NaOH solution at 80°C (ASTM C 1260) for 21 days Expansion of bar specimens was measured, and chemical analysis was performed at different ages using X-ray spectra and maps Test results confirmed that HRM and SF significantly reduce expansion due to ASR In addition, X-ray microanalysis showed that calcium content increases with time in ASR products Furthermore, it was found that as ASR proceeded the calcium content of reaction products increased proportionally as the silica content decreased

130 citations


Journal ArticleDOI
TL;DR: In this article, an experimental investigation on the effect of silica fume and size of aggregate on the long-term drying shrinkage of mortar is reported, and it was observed that the addition of Silica Fume has a significant influence on the drying shrinkages at early ages of mortar.

128 citations


Journal ArticleDOI
TL;DR: In this paper, electric polarization induced an increase of measured electrical resistivity of carbon fiber-reinforced cement paste during resistivity measurement, but the effect was diminished by increasing the conductivity of the cement paste through the use of carbon fibers that were more crystalline, the increase of the fiber content, or use of silica fume instead of latex as an admixture.

Journal ArticleDOI
TL;DR: In this article, a strain-sensing coating with short carbon fibers was found to be effective in the presence of short carbon fiber fibers and was tested on either the tension side or the compression side of a cement specimen under flexure.

Journal ArticleDOI
TL;DR: In this article, a comparative study of silica fume (SF) and dealuminated kaolin (DK) reactivities toward lime was conducted using isothermal conduction calorimetry and an accelerated chemical method.

Journal ArticleDOI
TL;DR: In this paper, the long-term effectiveness of six supplementary cementing materials (SCM) were tested according to the CSA-A23.2-14A Concrete Prism Method in the presence of two very alkali-silica reactive aggregates from Canada.

Journal ArticleDOI
TL;DR: In this article, the authors used acrylic dispersion as an admixture in the amount of 15% by mass of cement in order to improve the tensile properties of short carbon fibers.

Journal ArticleDOI
TL;DR: In this paper, the relative dielectric constant of cement paste at 10 kHz-1 MHz is decreased by silica fume addition (from 29 to 21 at 1 MHz) and by steel fiber addition ( from 29 to 20 at 1 kHz) due to the volume occupied by these admixtures in place of cement.

Journal ArticleDOI
TL;DR: In this paper, the effect of condensed silica fume (CSF) addition as a substitute material for Portland cement was investigated and the results showed that the severe retardation effect on ordinary Portland cement hydration caused by lead hydroxide has been minimized due to the pozzolanic effect and, as a result, the time to final setting has been significantly reduced.

Journal ArticleDOI
01 Nov 2001-Carbon
TL;DR: The tensile strength of cement paste was increased by 56% and the modulus and ductility were increased by 39% by using silane treated carbon fibers and silane-treated silica fume as mentioned in this paper.

01 Jan 2001
TL;DR: In this paper, the authors used acrylic dispersion as an admixture in the amount of 15% by mass of cement in order to improve the tensile properties of a mortar reinforced by short carbon fibers.
Abstract: Cement mortar reinforced by short carbon fibers was improved by using acrylic dispersion as an admixture in the amount of 15% by mass of cement. The improvement of the tensile properties (particularly strength and ductility) was more than those attained by using methylcellulose, styrene acrylic, or latex as admixtures. Acrylic was effective whether silica fume was present or not. However, for lowering the electrical resistivity, methylcellulose in combination with silica fume was most effective. D 2001 Elsevier Science Ltd. All rights reserved.

Journal ArticleDOI
TL;DR: The functional properties of cement-matrix composites are reviewed in this article, including strain sensing, damage sensing, temperature sensing, thermal control, vibration reduction and radio wave reflection.
Abstract: The functional properties of cement-matrix composites are reviewed The functions include strain sensing, damage sensing, temperature sensing, thermal control, vibration reduction and radio wave reflection The functions are rendered by the use of admixtures, such as short carbon fibers, short steel fibers and silica fume

Journal ArticleDOI
TL;DR: In this article, an experimental investigation on the variation of compressive strength, with water-binder ratios in mortars incorporated with silica fume, has been reported, and the strength development with w/b ratio has been studied at different ages of 3, 7, 28 and 90 days.

DOI
01 Jun 2001
TL;DR: In this paper, a preliminary research study on the role of rice-husk ash in enhancing the properties of high-volume fly ash concrete, particularly the early-age strength and chloride impermeability is presented.
Abstract: Blending fly ash with normal portland cement enhances the durability and service life of concrete structures. Fly ash-based blended portland cements containing 15-30% fly ash by mass are being increasingly used worldwide. These cements have been used in high-performance concrete for modern structures such as Petronas Towers, Euro-Tunnel, and Akashi-Kaikyo Bridge. High volume fly ash concrete is another recent development according to which, large volumes of fly ash, 50-60% by mass of the total cementitious material, can be used in combination with a superplasticizer to overcome the slow rate of strength development in blended portland cements. The chloride permeability of unsuperplasticized, high-volume fly ash concrete at early ages is rather high, but it can be greatly reduced by the incorporation of either silica fume or a highly pozzolanic rice-husk ash. Rice-husk ash is a siliceous material produced by furnaces that use rice-husks as fuel. The rice-husk ash containing amorphous silica in cellular microstructure is a superpozzolan, and has proven to be a valuable material for making highly durable concrete. It also contributes to concrete strength at early ages. This paper describes a preliminary research study on the role of rice-husk ash in enhancing the properties of high-volume fly ash concrete, particularly the early-age strength and chloride impermeability.

Journal ArticleDOI
TL;DR: In this article, the authors found that the extent of electric polarization in the transverse direction in cement pastes with and without carbon fibers, as shown by electrical resistivity measurement conducted over time, was much smaller when carbon fibers were present.

Journal ArticleDOI
TL;DR: A new technique for measuring the quantity of calcium silicate hydrate (C-S-H) in hydrated, blended cement pastes containing class F fly ash, ground granulated blast furnace slag, or silica fume is based on water adsorption.

01 Jan 2001
TL;DR: In this paper, compressive stress was found to diminish the extent of electric polarization in the transverse direction in cement pastes with and without carbon fibers, as shown by electrical resistivity measurement conducted over time.
Abstract: Compressive stress was found to diminish the extent of electric polarization in the transverse direction in cement pastes with and without carbon fibers, as shown by electrical resistivity measurement conducted over time. In addition, the stress decreased the time for polarization to essentially reach completion. The extent of polarization was much smaller when carbon fibers were present. It was smaller for carbon fiber cement paste containing silica fume than that containing latex. The time for polarization to reach completion was less than 5 s for carbon fiber silica fume cement paste at a compressive stress of 6.74 MPa. Polarization reversal was hastened by stress. D 2001 Elsevier Science Ltd. All rights reserved.

Journal ArticleDOI
TL;DR: In this article, the kinetics of the silica fume and dealuminated kaolin reactions were investigated in pastes at room temperature, 100°C, and 180°C by the determination of unreacted lime and combined water.

Journal ArticleDOI
TL;DR: In this paper, the electrical response characteristics of setting pastes can be used as an effective means of studying the progress of blended cement hydration and also for monitoring structural changes occurring within the paste, as well as reflecting the hydraulic reactivity of granulated slag and silica fume as pozzolanic constituents of the hardening pastes.

Journal ArticleDOI
TL;DR: In this paper, the influence of dose rate on the compressive strength of Portland cement based materials were investigated, including Portland I, Portland V, and Portland V wit silica fume (SP).
Abstract: This paper describes part of a research effort that investigates the influence of dose rate on the compressive strengths of Portland cement based materials These include Portland I, Portland V, and Portland V wit silica fume (SP)

Journal ArticleDOI
TL;DR: In this paper, the development of compressive strength with age of mortar incorporated with silica fume with different water/binder (w/b) ratios have been reported.

Journal ArticleDOI
TL;DR: In this paper, high-resolution 29 Si and 27 Al magic angle spinning (MAS) nuclear magnetic resonance (NMR) was used for analyzing concrete mixes, and the influence of the amount of silica fume and of the type of cement in high performance concrete (HPC) was investigated.