Tayyab, et al (2024) BiocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More in cementitious composites: A comprehensive review of properties, compatibility, and prospect of use in sustainable geopolymer concrete. Resources, Conservation & Recycling Advances. https://doi.org/10.1016/j.rcradv.2024.200242

Biochar, a carbon-rich material derived from biomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More through pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More, offers promising potential in sustainable construction, particularly in geopolymer concrete (GPC). Geopolymer concrete, a low-carbon alternative to traditional cement, uses aluminosilicate materials (such as fly ashAsh is the non-combustible inorganic residue that remains after organic matter, like wood or biomass, is completely burned. It consists mainly of minerals and is different from biochar, which is produced through incomplete combustion.   Ash Ash is the residue that remains after the complete More or slag) as binders. However, the declining availability of these materials has driven researchers to explore alternatives like biochar.

The review explores biochar’s compatibility with GPC, focusing on its chemical, physical, and mechanical properties. Biochar, rich in silica and alumina, can serve as a precursor material for GPC. When properly engineered, it supports geopolymerization, the process forming GPC’s durable binder matrix. Furthermore, its high alkalinity, derived from potassium oxides, enables biochar to function as a natural alkaline activator.

Compared to ordinary cementitious composites, GPC allows higher biochar incorporation, improving sustainability. Biochar contributes to reduced permeability, better thermal insulation, and carbon sequestration while maintaining compressive strength at optimal dosages (up to 5–10%). Additionally, biochar’s porous structure enhances internal curing, boosting long-term durability.

Challenges remain, including biochar’s heterogeneity and its effects on GPC’s workability. Standardizing biochar production and developing optimized mix designs are crucial for broader adoption. As an economical and sustainable resource, biochar aligns with global goals to reduce greenhouse gas emissions and promote circular economy practices in construction.

This innovation not only advances sustainable building materials but also provides a valuable use for agricultural waste, marking a step toward greener infrastructure.