CORRELATION OF CONCRETE CARBONATION PROCESS UNDER NATURAL CONDITION AND HIGH CO2 CONCENTRATION ARTIFICIAL ACCELERATED CLIMATE ENVIRONMENTS

Carbonation process of concrete under natural condition and its correlation with high CO2 concentration artificial accelerated carbonation are of a great concern. The pH values of carbonated concrete were measured, the variation of pH values was determined, and the variations of Ca(OH)(2) and CaCO3 contents in the carbonated concrete under the natural environment and the high CO2 concentration accelerated climate environments were determined by microcosmic test methods such as DTA and X-ray diffraction. The experimental results showed that the overall variation trend of pH Values and phase component of carbonation layer of concrete under accelerated climate environments with high CO2 concentrations were the same as those tinder natural conditions. Therefore, the carbonation processes of concrete were considered consistent under both conditions. However there was a difference in the length of semi-carbonation zones. The one measured under high CO) concentration accelerated climate environments was shorter than that under natural condition, which was caused by the differences climate condition (temperature and relative humidity) as well as the properties of the concrete. It is acceptable to simulate the natural condition by applying the high CO2 concentration artificial accelerated carbonation technique for the purpose of the study of carbonation process of concrete.