Study for Material Configuration and Producing Method to Achieve Carbonation Curing Concrete Pre-Cast Structural Elements

Reducing concrete’s CO2 emissions has become an urgent issue from the perspective of environmental considerations and circular economy. Under these circumstances, we have been developing concrete products that reduce CO2 emissions by using γ-dicalcium silicate (γ-C2S), which absorbs and fixes CO2 and increases its strength. In this paper, we describe the examination results about the formulation and production of relatively high-strength precast concrete members that significantly reduce CO2 emissions by using cement containing a large amount of ground granulated blast furnace slag (GGBS) as a binder, γ-C2S for admixture materials and carbonated curing. As a results, it is found that carbonation curing concrete can reduce CO2 emissions by approximately 90% compared to concrete using ordinary Portland cement. Furthermore, it is clarified that in order to carbonate the concrete deep inside, carbonation curing process should be initiated as early as possible after casting at low concrete strength state.