Resistance of Fly Ash Based High Performance Concrete to Acidic Environment

Fly ash is one of the residues generated in combustion of coal. Fly ash is generally captured from the chimneys of power generation facilities. Fly ash includes substantial amounts of silica (SiO₂), both amorphous and crystalline, and lime (CaO). Fly ash is commonly used to supplement Portland cement in concrete production, where it can bring both technological and economic benefits. Increased awareness of environmental hazards, steep rising prices of building materials, non-availability of space to stock the fly ash and other such factors have generated interest among the researchers to work on the gainful utilization of fly ash as an alternate building material with potential for replacing cement partially in constructions. Fly ash utilization in concrete not only reduces the cost due to cement savings but also contribute to reduced carbon-dioxide emissions contributing to environmental protection. It is well established by now that the concrete structures exposed to acidic environments deteriorated much faster when compared to their counterparts in non-aggressive environments. High-Performance-Concrete (HPC) is a new generation concrete which has the potential to perform well in aggressive environments. This paper presents the details of an experimental investigation planned to utilize fly ash in production of HPC. Acid attack tests have been conducted to measure the durability of HPC. This investigation is undertaken to study and define a better HPC mix containing locally available fly ash which can sustain in chloride and sulphate environments. The investigation examines the progressive deterioration of concrete mixtures containing various combinations of fly ash based HPC mixes exposed to sulphate and chloride solutions.