Effect of different concentrations of lime water on mechanical properties of high volume fly ash concrete

Abstract

High volume fly ash concrete typically has around 50% or more of the cement content of concrete replaced by fly ash. This material has potential to reduce the environmental impact associated with production of concrete. One constraint observed in high volume fly ash concrete is the slower strength gain leading to low 28 day compressive strengths compared to Portland cement concrete. Preliminary work at RMIT University has shown that use of ultrafine fly ash and lime water can improve the mechanical and material properties of high volume fly ash concrete. This paper presents an investigation on the effect of different concentrations of lime water as mixing water on mechanical properties of high volume fly ash concrete. Raw fly ash and ultra fine fly ash with different concentrations of lime water are used in making high volume fly ash concrete. Ultrafine fly ash is generated by grinding raw fly ash with a micronizer. Compressive strength, modulus of elasticity, flexural strength and drying shrinkage of high volume fly ash concrete are determined in the laboratory and the results are presented here. Comparison of the strength and elastic properties of different mixes indicates that the concentration of lime water influences the strength development of high volume fly ash concrete