Effect of w/b ratio and binder content on the properties of self-compacting high performance concrete (SCHPC)

Abstract

Silica fume is most commonly used mineral admixture both in high performance concrete (HPC) and self-compacting concrete (SCC). While the incorporation of silica fume in concrete has been extensively investigated in HPC and SCC, further researches are needed to optimize the dosage of silica fume and cement content in self-compacting high performance concrete (SCHPC). This paper presents the results of tests carried out to study the effect of w/b ratio and binder content (cement and silica fume content) on properties of SCHPC. Eighteen batches of concrete with binder content ranging from 500-600 kg/m(3) were produced at two w/b ratios (0.23 and 0.25); with silica fume amount varying from 0 to 20 percent by weight of cement. Super Plasticizer (SP) dosage, porosity, water absorption, compressive strength, modulus of elasticity, splitting tensile strength, autogenous shrinkage (AS) and hydration characteristics were evaluated for all SCHPC mixes. The results indicate that optimum w/b ratio and binder content (cement and silica fume content) is required to get better performance from SCHPC, as high cement content and silica fume dosage tend to deteriorate the overall performance owing to reduced mechanical performances, high degree of hydration and greater autogenous shrinkage in SCHPC mixes incorporating silica fume.