Fifty-four different concrete mixes were exposed to hot arid weather in Kuwait to monitor their extent of carbonation. Various parameters affecting carbonation such as water/cement ratio, cement content, type of cement, type and dosage of admixture, water-curing period and type of coating were investigated. For many of these variables, the carbonation depth and rate constant (K) are reported for an exposure period of 8.6 years.
The results show that the water/cement ratio is one of the main factors affecting carbonation. The values of 'K' ranged from 2.1 to 7.8 as the water/cement ratio increased from 0.45 to 0.8. Concrete made with white Portland cement carbonated less than ordinary or sulphate resisting cements. Two curing compounds were effective in reducing carbonation while two coating materials prevented carbonation after eight years of exposure.