Biochar as a Partial Cement Replacement Material for Developing Sustainable Concrete: An Overview

Abstract

Biochar (BC) is a porous carbon formed by pyrolysis of biomass at high temperatures under anoxic conditions. The use of pulverized BC as a cementitious materials mixture has recently gained research momentum because this usage can lock BC in inert materials and reduce cement consumption simultaneously. This paper presents a review on the use BC particles as an additive or cement replacement in cementitious composites over the last few decades. It comprehensively reviews and discusses the physicochemical properties of BC, as well as the influence of BC on the hydration kinetics, workability, physical properties, mechanical properties, and durability of mortar or concrete. The replacement of cement with 1%–3% BC, in weight, decreases the permeability and increases the mechanism strength of cementitious composites. The properties of the BC-cement composites is closely related to the carbonaceous particle fineness, feedstock, pyrolysis temperature, and treatment method of the BC. Further research is expected to discover BC-based cementitious material for preparing a specific BC for a specific use as cementitious mixture.