Engineering and environmental performance of eco-efficient self-consolidating concrete (Eco-SCC) with low powder content and recycled concrete aggregate

Abstract

Self-consolidating concrete (SCC) is an innovative type of concrete that requires little to no mechanical vibration, and can be consolidated into formwork under its own weight. While the precast concrete industry has fully adopted SCC because of its tremendous benefits, the overall use of SCC in the concrete market, particularly in the ready-mixed concrete production, is still very limited. One of the main obstacles that prevents the wide use of SCC is the high cost and environmental impact associated with the high powder (cement, cementitious materials, and filler) content. A new concept of eco-efficient SCC (Eco-SCC) was recently presented in Europe and Asia, which aims to achieve SCC behavior with a powder content comparable to conventional vibrated concrete. This paper presented a preliminary study of the development of Eco-SCC with low powder contents and recycled concrete aggregate (RCA). Results showed that while the lower amount of powder materials and the use of RCA did affect the fresh and hardened concrete behaviors of SCC, most of the mixtures included in the study showed good flowability, passing ability, stability as well as strength that well satisfied the criteria of SCC. An environmental performance evaluation was also performed to justify the environmental benefit of Eco-SCC. The study demonstrated that through the optimization of particle size distribution and the optimum use of chemical admixtures, it is possible to obtain Eco-SCC with engineering properties comparable to traditional SCC, yet more environmentally friendly.