The field of civil engineering is undergoing a quiet revolution, driven by the need for more sustainable and resilient infrastructure. A new study, “Self-sensing response of cementitious sensors with wood-based 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 and liquid MWCNTS,” published in Life-Cycle Performance of Structures and Infrastructure Systems in Diverse Environments, highlights a significant step forward. Authored by Jin-Hui Lee, Jin-Seok Woo, Jae-Yong Jeong, Hyun-Do Yun, Sun-Woo Kim, Wan-Shin Park, and Won-Chang Choi, this research explores the use of biocha as a key component in “self-sensing” cement. This innovation could lead to more durable, eco-friendly buildings that can monitor their own health in real time.

Keeping our bridges, dams, and high-rise buildings safe requires constant vigilance. Structural health monitoring (SHM) is a crucial technology for this, using sensors to detect internal stresses and deformations before they become a danger. While self-sensing cement composites (SSCCs) using materials like multi-walled carbon nanotubes (MWCNTs) are effective, their high cost and tendency to clump together (agglomeration) limit their widespread use. This is where biochar offers a promising solution. Produced by heating 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 with limited oxygen, biochar is a sustainable and cost-effective material with a porous structure. It’s already known for its ability to capture and sequester carbon dioxide, and this study explores its potential to act as a conductive material in sensors.

The research team set out to create a biochar-based sensor that could rival the performance of more expensive alternatives. They used wood-based biochar, which was ground to a fine powder and then treated with an iron chloride solution to enhance its electrical conductivity. Steel fibers were also added to the cement mixture for reinforcement and conductivity. The results were impressive. The biochar-based specimens (BCCC) showed a remarkable 25.5% higher average compressive strength compared to the plain cement control specimens (OPC). The authors suggest that the porous structure of the biochar helped retain moisture during the initial curing phase, which led to a denser and stronger final composite.

The study also evaluated the sensors’ piezoresistive performance—their ability to change electrical resistance in response to mechanical stress. The researchers used a repeated compression test, applying loads at increasing percentages of the material’s compressive strength. While the plain cement control had detectable electrical properties due to the steel fibers, it showed poor deformation recovery. The specimens with iron-treated biochar (FBCC) showed better strain recovery, but their performance became inconsistent when the load exceeded 70%. The real breakthrough came with the specimens that combined biochar and MWCNTs (FCCC). This hybrid sensor exhibited superior performance in both strain recovery and sensitivity. The combination effectively addressed the limitations of using MWCNTs alone. However, the researchers noted some unexpected interactions between the surface-modified biochar and the MWCNTs, suggesting that further investigation is needed to fully understand this synergy.

This research demonstrates that biochar is a viable, sustainable, and economical alternative to expensive carbon nanomaterials like MWCNTs for creating self-sensing cement. Its dual benefits of improving mechanical strength and providing a pathway for structural health monitoring make it a powerful tool for the future of construction. While some aspects, particularly the complex interactions in the hybrid sensors, require more study, the findings underscore the potential of biochar to create more intelligent, durable, and environmentally friendly infrastructure. The future of construction may be less about pouring cement and more about growing it.

Source: Lee, J.-H., Woo, J.-S., Jeong, J.-Y., Yun, H.-D., Kim, S.-W., Park, W.-S., & Choi, W.-C. (2025). Self-sensing response of cementitious sensors with wood-based biochar and liquid MWCNTS. In Li & Frangopol (Eds.), Life-Cycle Performance of Structures and Infrastructure Systems in Diverse Environments.