The hydration and heavy metal immobilization performance of the CO2-active incineration fly ash-calcined clay-cement (CFC3) composite low-carbon cementitious system

Abstract

CO2-active enhances the performance of municipal solid waste incineration fly ash as a supplementary cementitious material, increasing its utilization in cementitious systems. CFC3, a low-carbon cementitious material, effectively utilizes CO2-active incineration fly ash (CIFA). To minimize cement usage, the component effects on hydration need to be studied. In this study, hydration, mechanical and environmental properties of CFC3 were evaluated based on cement dosage and calcined clay/CIFA values. The maximum compressive strength of the samples reached 18.0 MPa at 3d and 47.6 MPa at 56d. The introduction of CIFA delayed the reactions of C3S and aluminates. Calcined clay contributes to improved gel polymerization, optimizes the Si/AlCASH ratio, and refines pore structure. A decrease in cement content increased in the aluminate phases, making monocarbonate the primary hydration product. The results of leaching tests indicated that Cd and Pb in R2C50 were transformed into non-leachable, inactive substances. Demonstrating the environmental friendliness of CFC3.