Effects of Curing Regimes on Calcium Oxide–Belite–Calcium Sulfoaluminate-Based Aerated Concrete.

This study delves into the effects of carbonation curing and autoclave–carbonation curing on the properties of calcium oxide–belite–calcium sulfoaluminate (CBSAC) cementitious material aerated concrete. The objective is to produce aerated concrete that adheres to the strength index in the Chinese standard GB/T 11968 while simultaneously mitigating CO2 emissions from cement factories. Results show that the compressive strength of CBSAC aerated concrete with different curing regimes (autoclave curing, carbonation curing, and autoclave–carbonation curing) can reach 4.3, 0.8, and 4.1 MPa, respectively. In autoclave–carbonation curing, delaying CO2 injection allows for better CO2 diffusion and reaction within the pores, increases the carbonation degree from 19.1% to 55.1%, and the bulk density from 603.7 kg/m3 to 640.2 kg/m3. Additionally, microstructural analysis reveals that delaying the injection of CO2 minimally disrupts internal hydrothermal synthesis, along with the formation of calcium carbonate clusters and needle-like silica gels, leading to a higher pore wall density. The industrial implementation of autoclavecarbonation curing results in CBSAC aerated concrete with a CO2 sequestration capacity ranging from 40 to 60 kg/m3 and a compressive strength spanning from 3.6 to 4.2 MPa. This innovative approach effectively mitigates the carbon emission pressures faced by CBSAC manufacturers. [ABSTRACT FROM AUTHOR]