Topic
Silica fume
About: Silica fume is a research topic. Over the lifetime, 10177 publications have been published within this topic receiving 173857 citations.
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TL;DR: In this paper, a model for predicting the compressive strength of concrete mixes at any age with the help of two constants ( A ) and ( B ) that are considered as a characteristic property for a concrete mix.
104 citations
TL;DR: In this paper, the internal curing of three different high-performance blended cement mortars was evaluated with respect to measured autogenous deformation and compressive strength development, and it was shown that internal curing is particularly beneficial for the mortars containing silica fume or slag blended cements.
Abstract: In the twenty-first century, most high-performance concretes, and many other ordinary concretes, are now based on blended cements that contain silica fume, slag, and/or fly ash additions Because the chemical shrinkage accompanying the pozzolanic and hydraulic reactions of these mineral admixtures is generally much greater than that accompanying conventional portland cement hydration, these blended cements may have an increased demand for additional curing water When such water cannot be supplied efficiently by external curing, internal curing becomes necessary, if the maintenance of saturated hydration conditions in the blended cement paste is desired In this paper, the internal curing of three different high-performance blended cement mortars is evaluated with respect to measured autogenous deformation and compressive strength development Internal curing is particularly beneficial for the mortars containing silica fume or slag blended cements For the blended cement containing a Type F fly ash, less autogenous deformation is observed, due to the maintenance of a more open (percolated) pore structure containing larger pores, as supported by low temperature calorimetry measurements on hydrated paste specimens In addition to providing a substantial reduction in autogenous shrinkage at early ages, internal curing also provided a significant increase in long term (28 d and beyond) compressive strength in the three mortars investigated in this study
104 citations
Book•
01 Jan 1991
TL;DR: In this article, the authors describe the physical and chemical properties of crystalline silica glass, and present a classification of the properties of these materials based on the characteristics of the raw materials.
Abstract: 1. Significance and Classification of Silica Glasses. 2. Raw Materials for Silica Glass Manufacture. Introduction. Natural raw materials. The structure and properties of crystalline silica. Condition for the formation of quartz. Rock crystal deposits. Vein quartz deposits. Quartz sand. Synthetic raw materials. Raw materials for the sol-gel method of silica glass production. Raw materials for the production of silica glass by thermal decomposition of silicon compounds. Methods for the evaluation of natural quartz raw materials. Density characteristics. Quartz-cristobalite phase conversion. Chemical analysis. Mineralogical analysis. Sieve analysis. Evaluation of the distribution of impurities. Light transmittance measurement. Light scattering measurement. Other supplementary methods. 3. The Technology of Silica Glass Manufacture. Silica glass. The quartz to silica glass phase transformation. Liberation of gaseous components during the heating of quartz. The effect of admixtures and accompanying minerals on the formation of silica glass. The effects of furnace atmosphere and furnace materials on the formation of silica glass. Reactions of synthetic raw materials. Thermodynamics aspects of the formation of silica glass. Structure of silica glass. Refining of natural quartz raw materials for the production of silica glass. Basic refining processes for the quartz raw materials. Methods of refining the quartz raw materials. Evaluation of refining methods. Technological methods of manufacture of silica glass. Opaque silica glass. Clear silica glass. Optical silica glass. Special methods of silica glass manufacture. Manufacture of Vycor type extractable glasses. 4. Physical and Chemical Properties of Silica Glasses. Chemical properties. Chemical composition. Resistance to water and aqueous solutions of salts. Durability with respect to acids. Durability with respect to alkalis. Durability with respect to other agents. Mechanical properties. Density. Modulus of elasticity and Poisson ratio. Strength of silica glass. Hardness. Propagation of sound waves. Thermal properties. Thermal expansivity. Resistance to thermal shock. Viscosity. Specific heat. Thermal conductivity. Permeability to gases. Surface tension. Crystallization properties. Electrical properties. Electrical resistivity. Electrical disruptive strength. Permittivity. Loss factor tan d. Optical properties. Reflection of radiation by silica glass. Optical refraction and dispersion by silica glass. Absorption of radiation by silica glass. Scattering of radiation by silica glass. Luminescence of silica glass. Resistance of silica glasses to the effects of radiation. Photoelasticity constant. 5. Application of Silica Glasses in Practice. Lighting technology. Semiconductor technology. Optical industry. Glass industry. Chemical industry and instruments. Metallurgy. Electrical engineering, electronics and communication technology. Astronomy and space research. References. Subject Index.
104 citations
TL;DR: A rotational rheometer was used to measure yield stress, viscosity and reversible stiffening behavior of ternary blends of fly ash-cement-micro silica as mentioned in this paper.
104 citations
Patent•
07 Jun 1993
TL;DR: A low cost cement composition that can be admixed with water and hydrothermally closed cured to give acid-resistant products of high compressive strength consisting essentially of, in parts by weight, 1 to 1.5 parts of a calcium oxide material containing at least about 60% CaO, 10 to 15 parts of pozzolanic material and 0.025 to 0.075 parts of an alkali metal catalyst and building materials made therefrom as well as the method of making such building materials by closed curing as discussed by the authors.
Abstract: A low cost cement composition that can be admixed with water and hydrothermally closed cured to give acid-resistant products of high compressive strength consisting essentially of, in parts by weight, 1 to 1.5 parts of a calcium oxide material containing at least about 60% CaO, 10 to 15 parts of pozzolanic material containing at least about 30% by weight amorphous glass or vitreous silica, and 0.025 to 0.075 parts by weight of an alkali metal catalyst and building materials made therefrom as well as the method of making such building materials by closed curing.
104 citations