The development of piezoresistive sensors for internal deformation detection and damage assessment in building maintenance is garnering significant attention. Traditional piezoresistive sensors using multi-walled carbon nanotubes (MWCNTs) are limited by their high cost. This study aimed to commercialize cement composite sensors incorporating biochar as a cost-effective alternative. Additionally, biochar was surface-modified with ferric chloride (FeClâ‚‚) aqueous solution to evaluate its potential for sensor applications and compatibility with MWCNTs. Mechanical property analysis confirmed that specimens with biochar exhibited higher average compressive strength. Electrical property analysis was conducted to assess the role of biochar as a sensor, focusing on strain recovery capability through repeated compression tests. Using an LCR meter, the fractional change in resistance (FCR) was analyzed, demonstrating the applicability of surface-modified biochar for sensing applications. A comparison of vertical strain and FCR values revealed that specimens incorporating both biochar and MWCNTs exhibited superior performance in terms of strain recovery capability and sensitivity. These findings suggest that further research on biochar-based sensors is necessary to explore their full potential.