Effect of temperature and salt contamination on carbonation of cements

This research was conducted to evaluate the concomitant effect of chloride and sulfate contamination and high temperature and humidity on carbonation in plain and blended cements. The cement mortar specimens were contaminated with chloride and sulfate ions and exposed to 55°C, 75% relative humidity (RH) and 3% CO₂ atmosphere. The progress of carbonation was evaluated by measuring the depth of the carbonated layer and the weight gain. Morphological changes due to carbonation were examined using scanning electron microscopy. The results indicated greater carbonation in the contaminated specimens than in the uncontaminated specimens. This was observed in both plain and blended cements. The increased carbonation in the contaminated specimens is attributed to changes in the pore structure of cement due to the inclusion of contaminants.