Development of a Sustainable CO2 Solidified Aerated Concrete

This study reports a CO2 solidified aerated concrete (CSAC) with gamma-C2S as the primary carbonatable binder. Several experiments were performed to test CSAC for its physical and mechanical properties. With the coupling positive effects of high carbonation reactivity of gamma-C2S and the addition of cellulous fibers, CSAC is characterized with high compressive strength, high and uniform carbonation degree, prominent strength-based CO2 absorption efficiency, and low energy consumption with a short CO2 curing duration. The uniquely wrinkled texture of cellulous fibers facilitates the inward diffusion of CO2 which explains the high degree of reaction and CO2 absorption. The results show that CSAC has a compressive strength of 4.5 MPa and a carbonation degree of 65.8% when the carbonation duration is only 2 h at 60% CO2 concentration, and the amount of solidified CO2 normalized with respect to the compressive strength and curing time of a mix (CO2 solidification efficiency) can reach 2.74 MPa-1 h(-1). The research provides a promising method for preparing aerated concrete with large-scale CO2 utilization to induce a sustainable stance for the concrete industry as it fulfills mandates for a lower carbon footprint.

Automated summary

This study presents a CO2 solidified aerated concrete (CSAC) using gamma-C2S as the primary binder. The addition of cellulose fibers enhances the compressive strength and carbonation efficiency of CSAC. The research provides a promising method for large-scale CO2 utilization in the concrete industry.