Abstract
Carbonation has been considered as a deterioration factor in concrete because it reduces the pH of concrete from between 12.6 and 13.5 to about 9. However, carbonation can have some positive consequences. Because CO3 occupies a greater volume than Ca(OH)2, which it replaces, the porosity of carbonated concrete decreases. On the other hand, carbonation turns bound chloride into free chloride. The results verify that carbonation has some beneficial effects by enhancing compressive strength and volume safety and reducing permeability and chloride ion penetration. In general, carbonation enhances concrete performance.
