Biochar-Added Cementitious Materials—A Review on Mechanical, Thermal, and Environmental Properties

TLDR

The construction sector’s high CO₂ emissions drive the search for mitigation, and biochar—a carbonised biomass—has emerged as a promising partial cement replacement that can enhance mechanical strength and thermal properties. This review aims to evaluate the properties of biochar and its effects on cementitious materials to guide researchers toward CO₂‑reduction and performance enhancement. The authors critically assess biochar’s mechanical and thermal performance, life‑cycle CO₂ impacts, and economic advantages within cementitious composites.

Abstract

The enhanced carbon footprint of the construction sector has created the need for CO2 emission control and mitigation. CO2 emissions in the construction sector are influenced by a variety of factors, including raw material preparation, cement production, and, most notably, the construction process. Thus, using biobased constituents in cement could reduce CO2 emissions. However, biobased constituents can degrade and have a negative impact on cement performance. Recently, carbonised biomass known as biochar has been found to be an effective partial replacement for cement. Various studies have reported improved mechanical strength and thermal properties with the inclusion of biochar in concrete. To comprehend the properties of biochar-added cementitious materials, the properties of biochar and their effect on concrete need to be examined. This review provides a critical examination of the mechanical and thermal properties of biochar and biochar-added cementitious materials. The study also covers biochar’s life cycle assessment and economic benefits. Overall, the purpose of this review article is to provide a means for researchers in the relevant field to gain a deeper understanding of the innate properties of biochar imparted into biochar-added cementitious materials for property enhancement and reduction of CO2 emissions.