Sustainable design and ecological evaluation of low binder self-compacting concrete

Self-compacting concrete (SCC) is a kind of high-performance concrete that is able to consolidate under its own weight without vibration. Due to its high binder content, the production of SCC normally needs a larger number of cement, the production of cement are associated with high energy consumption and CO2 emissions, which result in serious environmental pollution. To maintain the ecological sustainability of SCC, this research recommends a sustainable mix design method for SCC with a low binder content based on particle packing theory. The packing density of the concrete mixture is optimized by selecting an appropriate powder composition and particle gradation of the aggregate. Using the SCC mix design with the optimal packing density, a sustainable SCC can be achieved with the lowest possible of binder content while maintaining the desired level of workability and mechanical performance. The proposed design reduces the required binder content in the SCC mixture by 16%, the energy consumption during production of concrete by 30.57%, the CO2 emissions by 33.98%, and the material cost by 6.24%, respectively, compared with the typical mix design recommended by the American Concrete Institute (ACI C237) standard for similar 28-day compressive strength. The proposed mix design strikes a good balance between the ecological sustainability and performance based behaviors of SCC.