Corn waste-derived biochar as a sustainable fine aggregate in pervious concrete for climate-resilient urban pavement applications

This study introduces a novel pervious concrete incorporating corn waste-derived biochar as a partial replacement for natural fine aggregate. Unlike prior work that substitutes biochar for cement, this design uses biochar as a sustainable bio-fine aggregate, replacing 7.5–12 % of fine sand. The optimized mix (BPC3) achieved a 28-day compressive strength of 14.7 MPa, a total porosity of 27.3 %, and a water permeability of 4.21 mm/s. These values meet the functional requirements for permeable pavements. A cradle-to-gate life cycle assessment revealed a 21.6 % reduction in greenhouse gas emissions compared to conventional pervious concrete. This environmental benefit arises from carbon sequestration in biochar and avoided CO₂ emissions from the open-field burning of corn residues. These results demonstrate that corn-biochar pervious concrete can deliver the necessary mechanical and hydraulic performance while substantially reducing embodied carbon, offering a low-carbon solution for sustainable pavement construction.