Enhancement of Concrete Performance and Sustainability through Partial Cement Replacement with Biochar: An Experimental Study

India is one of the world’s largest rice-growing countries. The rice husk production in India is approximately 24 million tons per year. Biochar is a solid material prepared by pyrolysis of waste biomass. There are many potential uses for this waste. In the present study, various dosages of biochar (0%, 3%, 5%, and 10 wt.(%) were replaced with cement in high strength concrete (M55 grade), as filler. Fresh state properties such as water permeability, slump value, and compaction factor were examined according to ASTM standards. The mechanical properties, including compressive strength, split tensile strength, and microstructural properties, were analyzed using FESEM, XRD, FTIR, and TG/DTA and compared to those of the control concrete. The results showed that biochar contents of 3% and 5% by weight of cement improved the mechanical characteristics and internal microstructure of concrete. The results illustrated that concrete incorporating 3% and 5% biochar enhanced compressive strength up to 57 and 58 MPa, respectively, because the finer biochar particles had a packing effect, creating a denser matrix. Furthermore, embodied energy analysis of concrete with different biochar dosages was examined. It was inferred that biochar could partially replace cement in concrete mixtures. Reducing the quantity of cement used directly lowers the associated greenhouse gas emissions because cement production is a significant source of CO₂ emissions. Moreover, 3% and 5% of biochar substitution for partial cement in concrete provides a long-term solution for reducing cement consumption and promoting waste management.