Synergetic effect of fly ash and silica fume on the performance of high volume fly ash self-compacting concrete

ABSTRACT This paper is focused on the feasibility of replacing the cement with industrial wastes like fly ash (FA) and silica fume (SF). The goal is to improve the mechanical and durability characteristics of self-compacting concrete (SCC) and to find an application of high volume fly ash (HVFA) in SCC which can be environmentally sustainable. In this study, the replacement of cement with FA has been examined in various proportions from 0% to 100%. The durability properties of different SCC mixtures such as sorptivity and chloride ion penetration resistance were investigated. Similar tests were carried out with the incorporation of SF from 2% to 10% to the HVFA-SCC mixes. The mechanical properties of HVFA-SCC were significantly influenced by SF additions to the mixes. These mixtures showed low water penetrability and high resistance to penetration of chloride ion. Based on the experimental findings a relationship between sorptivity and chloride ion permeability has been projected. The synergetic effect of FA and SF on the performance of HVFA-SCC was done using the Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD) techniques. The study gives an indication of synergy arising from the pozzolanic activity and filler effects of SF in HVFA-SCC mixes.