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, type of coating, and the addition of silica fume or pulverized fuel ash were investigated. For many of these variables, the carbonation depth and rate constant (K) are reported for an exposure period of 8.6 years.