In Industrial Crops & Products, Zhonghao Li and colleagues, published research exploring the use of 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 from agricultural waste to improve cement mortar. Their study found that incorporating biochar, particularly from peanut shells, enhances cement mortar’s mechanical strength and significantly reduces shrinkage. This offers a promising avenue for more sustainable construction materials.

The researchers prepared biochar mortar by substituting cement with biochar derived from peanut shells, corncob, and wood chips, at levels of 1.0%, 3.0%, and 5.0%. They then meticulously examined the mortar’s workability, mechanical strength, shrinkage, composition, and microstructure. Workability decreased as biochar content increased, with peanut shell biochar mortar maintaining the best fluidity among the biochar types.

Mechanical strength initially improved, peaking at a 3.0% biochar substitution rate, before declining at higher concentrations. Notably, peanut shell biochar mortar surpassed ordinary cement mortar, showing increases in 28-day flexural and compressive strengths by 6.6% and 8.8%, respectively. This improvement is likely due to biochar’s porous structure, which aids in lowering the water-cement ratio and creating a denser cement structure. High biochar content, however, can lead to clumping, which weakens the material.

The study also demonstrated that shrinkage in cement-based materials lessened with increased biochar substitution. Peanut shell biochar mortar exhibited a substantial 25.3% reduction in 28-day shrinkage compared to regular mortar. Microscopic analysis identified the main mineral components of the biochar-modified cement as Ca(OH)2​, CaCO3​, ettringite, and C-S-H gel.

Furthermore, peanut shell biochar provides environmental benefits. Cement mortar with 3.0% peanut shell biochar reduced CO2​ emissions by 19.0% compared to ordinary cement mortar, highlighting biochar’s potential to support more environmentally friendly construction practices.

Source: Li, Z., Wang, X., Wang, S., & Feng, X. (2025). Comparative study on the effect of agricultural waste biochar on the properties of cement mortar. Industrial Crops & Products, 227, 120854.