Environmental assessment of several paths toward a carbon neutral ready-mixed concrete sector

To prevent serious consequences of climate change, it is essential to reduce greenhouse gas emissions, especially CO₂. The concrete industry, largely made up of ready-mixed reinforced concrete (RC), is a key part, as concrete is produced more than all other construction materials combined. This study evaluates decarbonization strategies in the RC sector, including low-clinker concrete (concrete with limestone calcined clay cement - LC 3 and high-volume limestone powder concrete - HVLPC), carbon capture and storage (CCS) and concrete with carbonated recycled aggregates (CRAC). Life cycle assessment was conducted on a typical RC floor slab under current and future conditions, including CCS and full electricity decarbonization. Results show a 60%–90% CO₂ reduction at the concrete level, but only ∼50% overall due to reinforcement impact—insufficient for net-zero under the assumptions made in this study. The best option combines HVLPC, oxyfuel CCS, and green electricity. With CCS and fully decarbonized electricity implemented in the future scenario, differences between conventional and low-clinker concretes drop below 10%. Possible mitigation strategies that can contribute to achieving carbon neutrality in the RC sector are decarbonization of the steel sector, increasing bioenergy and/or green hydrogen use in the kiln's fuel mix and decarbonization of transport.