Biochar as a Sustainable Cement Replacement for Enhancing Concrete Composite Properties: A Review
Mustapha Mahi, Md. Abdul Mun-Im-Dinar, Tanjun Ashravi Ridoy
Abstract
Concrete, a highly adaptable and extensively utilized material, encounters difficulties stemming from the environmental repercussions of cement manufacturing and the exhaustion of natural resources such as river sand and gravel. These concerns have stimulated investigation into sustainable alternatives like biochar, a carbon-dense substance generated by the thermochemical conversion of biomass. Biochar’s distinctive characteristics, such as elevated surface area, porosity, and cation exchange capacity, render it a viable supplemental cementitious material (SCM). This study evaluates the impact of biochar inclusion on concrete’s mechanical characteristics, concentrating on compressive, tensile, and flexural strengths. Research indicates that biochar enhances early-age compressive strength, with findings documenting an increase of up to 40% at a 2% replacement rate. Nonetheless, elevated doses (>5%) diminish strength owing to heightened porosity and water requirements. Flexural strength exhibited considerable enhancements, especially with presoaked biochar and certain feedstocks, but tensile strength advantages were noted at less replacement levels (e.g., 5%). The results underscore biochar’s potential as a supplementary cementitious material for sustainable concrete, including enhancements in early-age strength and environmental advantages such as carbon sequestration. Future research should concentrate on improving biochar dose and assessing long-term performance to improve its applicability in extensive building uses.