It aimed to investigate the effect of carbonation-hydration coupling curing mechanism on the CO2 uptake,compressive strength,volume stability and Cr leaching of cement paste containing high content of stainless steel slag.Cement paste was exposed to CO2(99.9%,0.2 MPa)for carbonation curing after hydration for 3 d,7 d and 28 d.The results indicated that carbonation-hydration procedure has a significant impact on the compressive strength of hardened paste.Hardened pasted carbonation curing for 1 h,2 h,and 6 h after hydration curing for 3 d can increase the compressive strength by 16.3%,26.5%,and 50.2%,and the hydration reaction will continue and impart the paste a continuously increasing compressive strength.The compressive strength of 28 d increased by 17.6%,27.7%,22.8%.The CO2 uptake and Cr leaching of the paste also depends on carbonation-hydration coupling curing mechanism.C2S,C3S and the hydration products(C-S-H gel and Ca(OH)2)can react with CO2 to form stable calcium carbonate.C-S-H gel and Ca(OH)2 show better carbonation activity than that of C2S,C3S,thereby samples exposed to CO2 after 28 d hydration curing absorb most CO2.Carbonation-hydration curing show excellent solidification effect on Cr from stainless steel slag,and the Cr leaching of samples carbonated for 6 h after hydration for 3 d decreased by 58.2%compared to the reference samples.
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