THE BEHAVIOR OF CONCRETE IN HOT CLIMATES

The paper, after very briefly discussing the classification of world climates, considers hot climates before taking up a review of papers dealing with the effects of hot climates on the properties of both fresh and hardened concrete. Raw materials for concrete are discussed, where the adverse and positive effects of C3A and gypsum contents of Portland cement, thermal movement of concrete and sulphate and chloride contents of aggregate and mixing water in hot climates are pointed out. The effect of elevated temperature, ambient and initial paste temperature, ambient relative humidity, solar radiation, and water/cement ratio on the rate of Portland cement hydration and hydration product structure are discussed. The behaviours of both fresh and hardened concrete are taken up. The effect of evaporation from a fresh concrete surface on the behaviour of hardened concrete is discussed. The paper concludes that the presently published works on the properties of concrete in hot climates are fragmentary, uncoordinated and at times contradictory. It points out that systematic studies of the properties of concrete cast and continuously exposed to either hot-humid or hot-dry climates remain to be done.