Investigation on enhancing the mechanical properties of Alkali-Activated concrete based on fly ash with wollastonite

Abstract

Alkali-activated concrete (AAC) is one of the cement-free concretes. It has attracted attention as a notable alternative to conventional Portland Cement Concrete (PCC) due to its superior mechanical properties and environmental benefits. This study investigates the impact of wollastonite, an industrial mineral composed chemically of calcium, silicon, and oxygen, on the mechanical properties of fly ash-based AAC. The compressive strength, split tensile strength and flexure strength at the different liquid-to-binder ratios (such as 0.35, 0.40 and 0.45) are examined. The partial replacement of fly ash with mineral wollastonite powder was carried out at different percentages varying from 5% up to 30%. Samples are cured using both oven curing and ambient curing procedures, and the test results are obtained. In the observation, the best test results are obtained at 20% replacement of fly ash with wollastonite irrespective of liquid-to-binder ratio values. Hence, the AAC with a composition of 20% wollastonite and 80% fly ash has been recognized to have optimum mechanical properties. The findings of this study would largely help to achieve the goals of “zero-waste” production.