Effect of replacement of fly ash with silica fume on durability properties of self-compacting concrete

Abstract

The durability of self-compacting concrete (SCC) is a crucial factor in ensuring long-term structural performance, particularly in aggressive environments. This study investigates the influence of replacing fly ash with silica fume on the durability properties of SCC. Concrete mixes were prepared by partially substituting fly ash with silica fume at varying replacement levels, and their performance was assessed through water absorption and rapid chloride permeability (RCPT) testing. The results indicated that the incorporation of silica fume significantly reduces both water absorption and RCPT, demonstrating improved resistance to water ingress. This enhancement can be attributed to the densification of the microstructure and the refinement of pore distribution due to the high pozzolanic reactivity of silica fume. The findings highlight that replacing fly ash with silica fume contributes to superior durability characteristics of SCC, making it a promising material for sustainable and long-lasting concrete structures.