Biochar-Enhanced Carbon-Negative and Sustainable Cement Composites: A Scientometric Review

The increasing demand for cement, driven by global urbanization and infrastructure expansion, necessitates the adoption of sustainable alternatives as construction materials. Cement-based composites, a prevalent construction material, are known for their high carbon footprint. Consequently, exploring sustainable alternatives is urgently needed to mitigate the environmental impact of the construction sector by capturing carbon dioxide (CO₂). Utilizing biochar (BC) in cement-based composites—either as an additive, cement replacement, or aggregate replacement—could be a green approach to producing enhanced composites with CO₂ sequestration capabilities. This review investigates BC-modified cement composites by performing a scientometric assessment of the Scopus database, supplemented by a thorough manual review. A scientometric analysis of Scopus-indexed publications (2010–2024) was conducted to highlight key research trends, including influential authors, frequently cited works, contributing countries, and institutions. The findings provide a comprehensive overview of the current state of BC research and applications in cement-based composites for sustainable construction. The assessment revealed that the Construction and Building Materials journal was the most prolific source of publications (n = 34), followed by Gupta (n = 11) as the most prolific author, and China (n = 56) as the leading country in the field. Emerging areas for the use of BC in the construction sector for CO₂ sequestration and potential future directions are also highlighted. Additionally, the review discusses BC sources, production technologies, and characteristics, as well as the influence of BC inclusion on fresh properties, mechanical properties, durability characteristics, carbon capture capabilities, and the environmental impacts of modified cement-based composites. Notably, BC addition to cement-based composites at 1%–2% levels can enhance mechanical performance. However, replacements beyond 5%–6% resulted in declines compared to non-modified composites. BC addition reduced the flow characteristics of modified composites due to its porous morphology and hydrophobic nature but demonstrated improved internal curing and reduced shrinkage. The microstructure of the cement-based composite was also enhanced through pore refinement, attributed to the filling ability of BC particles, which is related to their specific surface area and size. Moreover, the carbon sequestration potential of BC can be exploited in cement-based composites to create low-carbon or carbon-negative building materials with improved mechanical and durability characteristics. This study highlights future directions for further research and large-scale implementation strategies for BC as a sustainable construction material. Keywords: biochar; biochar-based composites; scientometric analysis; mechanical properties; durability; carbon sequestration; sustainability