Application of silica fume in high-volume fly ash self-compacting recycled aggregate concrete

ABSTRACT Recent advancement in construction practices demands the utilisation of construction materials in a sustainable way which promotes the use of industrial by-products as Supplementary Cementitious Materials (SCMs) and alternative aggregates to protect diminishing natural resources. The present study proposed the utilisation of high-volume fly ash in the production of Self-Compacting Concrete (SCC) made with varying proportions of coarse and fine recycled aggregates. Natural Aggregates (NA) of both coarse and fine type in high-volume fly ash SCC were replaced with the respective type of recycled aggregates at the dosage of 0%, 50% and 100% by volume and their hardened state behaviour was studied in terms of compressive strength, chloride ion permeability, initial rate of water absorption, sorptivity coefficient and sulphate resistance. Results of the investigation recommends uses of Silica Fume (SF) at 10% dosages in ternary blends of cement along with high-volume fly ash for the production of SCC at 50% replacement level of both coarse and fine recycled aggregates, without compromising the hardened state properties of concrete.