Biochar offers a low-carbon pathway for stronger and more sustainable concrete
image: The state-of-the-art review on biochar as green additives in cementitious composites: performance, applications, machine learning predictions, and environmental and economic implications
Credit: Ping Ye, Binglin Guo, Huyong Qin, Cheng Wang, Yang Liu, Yuyang Chen, Pengfei Bian, Di Lu, Lei Wang, Weiping Zhao, Yonggan Yang, Li Hong, Peng Gao, Peiyong Ma, Binggen Zhan & Qijun Yu
A new comprehensive review highlights how biochar, a carbon-rich material derived from biomass, could transform the cement industry by reducing emissions while improving the performance of construction materials.
Cement production is responsible for about 8 percent of global carbon emissions, making it one of the most carbon-intensive industries worldwide. Researchers are increasingly searching for sustainable alternatives that can maintain or even enhance material performance while lowering environmental impact. Biochar has emerged as a promising solution due to its carbon-negative properties and versatile functionality.
“Biochar provides a unique opportunity to simultaneously address carbon emissions and material performance in the construction sector,” said the study’s corresponding author. “By integrating biochar into cement-based materials, we can move closer to achieving carbon neutrality while improving durability and functionality.”
Produced through the pyrolysis of biomass such as agricultural and forestry waste, biochar is a porous and stable material with a high surface area and rich carbon structure. These characteristics allow it to interact effectively with cement matrices, influencing both physical and chemical properties.
The review shows that adding appropriate amounts of biochar can significantly improve the mechanical strength of cementitious composites. Biochar particles can fill microscopic pores, enhance bonding within the material, and promote hydration reactions, leading to increased compressive and flexural strength. However, the researchers caution that excessive amounts may reduce performance, highlighting the importance of optimizing dosage.
Beyond strength, biochar also enhances durability. Its porous structure can improve resistance to water penetration and harmful chemical intrusion, extending the lifespan of concrete structures. At the same time, biochar can reduce thermal conductivity, improving insulation performance and potentially lowering energy consumption in buildings.
The material also contributes to additional functional benefits. Biochar-modified cement can offer improved fire resistance, sound absorption, and even microwave shielding properties, opening new possibilities for advanced construction applications.
Another key finding of the study is the growing role of machine learning in this field. Traditional testing of cement materials is time-consuming and influenced by many variables. Machine learning models can help predict the performance of biochar-enhanced composites more efficiently, accelerating material design and reducing experimental costs.
Despite these advantages, challenges remain. The properties of biochar can vary depending on feedstock type and production conditions, which affects its performance in cement systems. Additionally, potential environmental risks, such as the presence of contaminants in certain biochar sources, must be carefully managed.
The researchers emphasize the need for standardized production methods, improved life-cycle assessments, and stronger collaboration between academia, industry, and policymakers to fully realize the potential of biochar in construction.
As global demand for sustainable infrastructure continues to grow, biochar-based materials could play a key role in reshaping the future of the built environment. By turning waste biomass into a valuable construction resource, this approach not only reduces emissions but also supports a circular economy.
The study provides a roadmap for future research and industrial application, suggesting that with continued innovation and optimization, biochar could become a cornerstone material in the transition toward low-carbon construction.
===
Journal Reference: Ye, P., Guo, B., Qin, H. et al. The state-of-the-art review on biochar as green additives in cementitious composites: performance, applications, machine learning predictions, and environmental and economic implications. Biochar 7, 21 (2025).
https://doi.org/10.1007/s42773-024-00423-1
===
About Biochar
Biochar (e-ISSN: 2524-7867) is the first journal dedicated exclusively to biochar research, spanning agronomy, environmental science, and materials science. It publishes original studies on biochar production, processing, and applications—such as bioenergy, environmental remediation, soil enhancement, climate mitigation, water treatment, and sustainability analysis. The journal serves as an innovative and professional platform for global researchers to share advances in this rapidly expanding field.