Biochar as a carbon sequestering construction material in cementitious mortar

Abstract

Recent efforts to attain carbon negative construction practices in Singapore and other developed countries leads to a search for construction materials that can reduce net carbon emission associated with concrete constructions. One such material is biochar which can sequester fixed carbon in its structure. Therefore, using biochar as a mixed-in component in cementitious material can reduce the net greenhouse emission associated with concrete constructions. Our study focuses on application of biochar derived from mixed-wood saw dust as a cement replacement in mortar. Experimental findings suggest that, due to its fine particle size and microfiller effect, up to 4% cement replacement by biochar yielded slight improvement in compressive strength while reducing sorptivity by about 70% after 28 days. Improvement in strength and permeability of mortar by incorporating biochar suggest that it can be successfully deployed as a carbon sequestering concrete construction material. Durable and strong infrastructure means reduced vulnerability to damage and thus need for subsequent repairs over its service lifespan. This will help contribute toward economic and environmental sustainability of buildings.