Overview
- RMIT researchers report a cradle‑to‑grave life‑cycle assessment showing CO2 reductions of 15%, 23% and 26% when coffee‑ground biochar replaces 5%, 10% and 15% of sand in concrete.
- The study, led by Dr. Jingxuan Zhang and Dr. Mohammad Saberian, appears in the International Journal of Construction Management and also finds up to 31% lower fossil‑fuel use and improved impacts on rivers and lakes.
- Earlier lab work showed that substituting 15% of sand with coffee‑derived biochar increased 28‑day concrete strength by about 30%, indicating performance gains alongside environmental benefits.
- Biochar is produced by heating spent coffee grounds to about 350°C in low oxygen, creating a carbon‑rich material that becomes locked within the concrete matrix.
- Public pilots have included a footpath trial and a section on the Victorian Big Build, and the team is now working with industry and government on larger pilots, mix optimization and alignment with construction standards.