Mechanical and durability studies on concrete containing wollastonite–fly ash combination

Several materials including fly ash, silica fume, metakaoline, wollastonite etc. which are either industrial wastes or naturally occurring minerals, have been investigated for making durable concrete material. Fly ash, silica fume, marble slurry etc. have been used in combination with wollastonite in cement concrete mixes for property enhancement. Huge amount of fly ash is being produced in India every year. It is expected to reach 225 million tons by 2017, creating its disposal problem which can be minimized by utilizing it in useful applications. The present investigation has been aimed to determine the influence of wollastonite–fly ash (W–FA) combination on properties of concrete such as strength, permeability, and durability over a range of water–binder (w/b) ratios and cement replacement. The microstructure and mercury intrusion porosity results of concrete mixes indicated that increased replacement levels of cement by W–FA combination (45–55%) causes some densification resulting into their enhanced mechanical and durability properties.