Feasibility study of novel Bengal Gram Husk Ash as a supplementary cementitious material: mechanical, durabilty and microstructural assessments

The research in countries like India demands the agricultural based wastes to be used as supplementary cementitious materials (SCM). Wastes like rice husks, sugarcane bagasse is released in huge quantity which are converted into ash and successfully applied as SCMs. This paper aims to identify a novel agricultural waste which would enhance the property of cement concrete thereby enhancing the sustainability as well. As per the literatures, agro-products like corn straw ash and peanut shell ash were also adopted in concrete which proved to improve the mechanical and durability properties. An innovative recent literature proved that, green gram pod ash in small dosage (8%) enhances the concrete properties. In this research, another popular agricultural product viz., Bengal Gram Husk Ash (BGHA) is experimented as SCM in cement mortar, which was not attempted so far in literatures. BGHA was prepared by burning the waste bengal gram husks in open burning method and sieved. The dosage of BGHA beyond 10% resulted in poor workability thus it was limited to 10% within which 2% increments were considered for mechanical, durability and microstructural assessments. Results revealed that 8% replacement of BGHA enhances the 28-days compressive strength upto 45% compared to reference mix. 10% BGHA mix showed reduction in compressive strength compared to 8% dosage, but however it improved the compressive strength of control mix by 40%. According to SEM analysis, BGHA has the capability to densify the matrix microstructure by occupying the pores/flaws in the cement matrix thereby enhances the property of concrete. Inclusion of BGHA showed three times more efficiency in arresting the external chemical influences like chloride, sulphate, seawater and capillary water rise. The developed mortar mix is more significant as they are eco-friendly, sustainable and technically beneficial. BGHA imposed mortar can be applied for special practical situations like tunnels, bridges and marine structures because of better durability and mechanical properties.