Hydration and Carbonation Properties of Different Hydraulic Lime

The main mineral phases of natural hydraulic lime (NHL) as a hydraulic lime binderare Ca(OH)2, C2S, C3S, C3A, and SiO2 residues. Also, NHL has the characteristic of setting and hardening by a hydration reaction with water and by carbonation reactions with carbon dioxide from the air. In this study, in an effort to investigate changes of the mineral phases by NHL hydration and carbonation reactions, transitions of mineral phases and the microstructures of hardened pastes were analyzed by XRD, DSC, SEM, and by pore size distributions using domestic and foreign-sourced NHL pastes after curing at 1, 3, 7, and 28 days. On the basis of the analysis results, it was confirmed that domestic low-grade limestone can be used for the manufacturing of NHL. The main hydration mineral phases were Ca(OH)2, CaCO3, C2S, and SiO2 residues, while in the case of foreign-sourced NHL, a small amount of an aluminium hydration phase formed. Also, the CaCO3 content after the carbonation reaction increased with an increase in the curing time. After hydration for 28 days, NHL containing considerable amounts of C2S and C3S showed higher carbonation ratios than others types.