Tag Archives: Fly ash

Current Situation of Supplementary Cementitious Materials (SCMs) in Canada

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The report details the current situation of supplementary cementing materials -SCMs- in Canada specifically in terms of production cost availability usage potential areas for increasing usage local barriers and relevant guidelines and specifications. The purpose of the study is to determine a strategy to increase the use of SCMs in Canada.

The data show that approximately 524 000 347 000 and 37 000 tonnes of fly ash Ground Granulated Blast Furnace Slag -GGBFS- and silica fume were used in cement and concrete applications in 2001. These amounts represent 11 90 and 185% of the quantity produced respectively. Thus fly ash appears to be the only material that is underused and that represents a potential for increased use of SCMs in Canada.

The investigation also shows that there are policy technical and economic barriers to the increased use of SCMs in Canada. The report suggests several solutions to overcome these barriers.

Includes an extensive list of tables.

Technical Report Author: Nabil Bouzoubaa, Benoit Fournier

Mechanical Properties and Durability of Concrete Made With High Volume Fly Ash Blended Cements Using a Coarse Fly Ash

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This paper presents a study on the mechanical properties and durability of concrete made with a high-volume fly ash blended cement using a coarse fly ash that does not meet the fineness requirement of ASTM C 618. The results were compared with those of the HVFA concrete in which unground fly ash had been added at the concrete mixer. The properties of the fresh concrete determined included the slump air content slump loss stability of air content bleeding and setting time; those of the hardened concrete investigated included the compressive strength flexural- and splitting-tensile strengths Young’s modulus of elasticity drying shrinkage resistance to abrasion chloride-ion penetration freezing and thawing cycling and to de-icing salt scaling. The results show that except for the resistance of the concrete to the de-icing salt scaling the mechanical properties and the durability of concrete made with this blended cement were superior to the concrete in which the unground fly ash and the cement had been added separately at the mixer. The production of HVFA blended cements therefore offers an effective way for the utilization of coarse fly ashes that do not otherwise meet the fineness requirements of ASTM C 618.

This paper was originally published in Cement and Concrete Research Vol. 31 No. 3 Oct. 2001. It includes a list of tables and figures detailing the results of the studies.

Technical Report Author: M.H. Zhang, Nabil Bouzoubaa, V.M. Malhotra, CANMET Energy Technology Centre, Natural Resources Canada,

Development of Ternary Blends for High-Performance Concrete

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The purpose of this study was to develop ternary blends with optimum amounts of fly ash and silica fume to be used in high-performance concrete. Two series of air-entrained concrete mixtures were investigated in the study: series 1 included concretes with a total cementitious materials content -CM- of 350 kg/m 3 and a water-to-cementitious materials ratio -W/CM- of 0.40 and series 2 included concretes with a total CM of 450 kg/m 3 and a W/CM of 0.34. In each series one silica fume and three fly ashes were used; these consisted of two ASTM Class F and one ASTM Class C fly ashes. Properties of the fresh and hardened concrete such as slump air content bleeding setting time autogenous temperature rise plastic shrinkage compressive strength drying shrinkage and the resistance to chloride-ion penetration were determined. The results show that the combined use of fly ash and silica fume in concrete are more advantageous in terms of the following parameters: the dosage of superplasticizer plastic shrinkage chloride-ion penetrability and the drying shrinkage. The report includes various tables and figures detailing the results of the study.

Technical Report Author: Nabil Bouzoubaa, Alain Bilodeau, Benoit Fournier, V. Sivasundaram, D.M. Golden, CANMET Energy Technology Centre, Natural Resources Canada,

Coal Ash: Its Origin, Disposal, Use and Potential Health Issues

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Millions of tons of coal ash are produced worldwide each year. EPRI and others have done extensive studies over many years of the nature of coal ash and its possible effects on the environment and human health. This Environmental Focus feature summarizes this information applicable regulations that govern the handling and use of coal ash and the benefits that can result from its use. EPRI concludes that the health risks from coal ash are minimal that the general public does not encounter coal ash in such proportions that it would present health risks and that radiation from fly ash and products made with fly ash is well below the Environmental Protection Agency s action standards. Further EPRI argues that use of fly ash as a recycled material can have economically and environmentally beneficial results.

Technical Report Author: Electric Power Research Institute (EPRI)

Self Compacting Concrete Incorporating High Volumes of Class F Fly Ash: Preliminary Results

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In recent years self-compacting concrete -SCC- has gained wide use for placement in congested reinforced concrete structures with difficult casting conditions. For such applications the fresh concrete must possess high fluidity and good cohesiveness. The use of fine materials such as fly ash can ensure the required concrete properties.

This paper presents the initial results of an experimental program aimed at producing and evaluating SCC made with high-volumes of fly ash. Nine SCC mixtures and one control concrete were investigated in this study. The content of the cementitious materials was maintained at 400 kg/m 3 while the water/cementitious material ratios ranged from 0.35 to 0.45. The self-compacting mixtures had a cement replacement of 40 50 and 60% by Class F fly ash. Tests were carried out on all mixtures to obtain the properties of fresh concrete in terms of viscosity and stability. The mechanical properties of hardened concretes such as compressive strength and drying shrinkage were also determined. The self-compacting concretes developed 28-day compressive strengths ranging from 26 to 48 MPa. The results show that an economical self-compacting concrete could be successfully developed by incorporating high-volumes of Class F fly ash. Includes tables and figures detailing the results.

This paper was originally published in Cement and Concrete Research Vol. 31 No. 3 Mar. 2001.

Technical Report Author: Nabil Bouzoubaa, M. Lachemi