Carbon sequestering biochar incorporated cementitious composites: Evaluation of hygrothermal, mechanical and durability characteristics

In the realm of sustainable construction materials, this study delves into the feasibility of utilizing wood-derived biochar as a partial substitute for sand in mortar. Carbon mineralisation potential of mortar increases due to the presence of biochar. Inclusion of biochar leads to improved thermal performance, manifested through reduced thermal conductivity, and increased specific heat capacity. Water vapour resistance factor also benefits from biochar, peaking at a 15% mixture. However, it is essential to acknowledge that these hygrothermal and carbon sequestration advantages comes at a cost: higher biochar contents lead to reduced strength, increased drying shrinkage and reduced sulphate resistance. The primary focus of this research lies in striking a balance between hygrothermal performance and environmental performance, particularly for indoor building applications. Furthermore, this research underscores the necessity of tailoring biochar-cementitious composite materials to their intended application context, capitalizing on their inherent strengths while mitigating potential weaknesses.