Influence of silica fume on mechanical and fracture properties of high performance concrete

Abstract

The main aim of this study is to determine the fracture energy of high performance concrete (HPC) containing silica fume (SF). The article presents the investigation on changes of the mechanical properties including compressive strength, splitting tensile strength, modulus of elasticity, fracture energy, and characteristic length of six HPC caused by the addition of SF. Additions of SF into the HPC were 0%, 5%, 10%, 15%, 20% and 25% by weight of cement content. The water/binder ratio was 0.25. The use of SF increased all tested mechanical properties of concrete. The study indicates that the mechanical properties of HPC were improved to a great extent at 28 days when cement used in concrete was replaced by SF. A 10% content of silica fume resulted in a 26% increase in tensile splitting strength, a 13% increase in compression strength and a 5% increase in the static modulus of elasticity. The brittleness of HPC increased with the presence of SF. The findings suggest that SF can effectively replace cement. Nevertheless, it is recommended that the replacement should not exceed 10%.