Effect of chelator on carbon sequestration and mechanical properties of CO2-cured cement pastes with different pore structures

Chelator can accelerate the mineralization reaction of cement-based materials, playing a positive role in reducing CO2 emissions into the atmosphere. Cement pastes with different pore structures were prepared by adjusting the water cement ratio, and effects of chelator on the microstructure, phase composition, carbon sequestration and mechanical properties of CO2-cured cement pastes with different pore structures were investigated in this study. The results indicated that chelator could promote CO2 transport in dense cement paste with more gel pore and transition pore and medium dense cement paste with many transition pore and capillary pore, and induce mineralization reaction to repair larger pores in loose cement paste with more capillary pore and megalopore (LCM). Chelator had the most significant effect on improving the performance of cement paste of LCM, increasing the carbonation sequestration rate and compressive strength of cement paste cured for 48 h by 19.0 % and 28.1 %, respectively.