Microstructural evolution and compressive strength enhancement of mortar containing spent coffee ground biochar as a sustainable fillerJidsucha Darayen, Chanikarn Vukthong, Chanachai Thongchom and Sutha KhaodhiarE3S Web Conf., 712 (2026) 09002DOI: https://doi.org/10.1051/e3sconf/202671209002