Effect of self-curing admixture on concrete properties in hot climate conditions

Hot climates prevail in many regions of the globe. The average summer temperature of hot arid areas is in the range of 40-50 degrees C with temperatures exceeding these values under direct solar radiation. Curing concrete in these regions may be challenging due to limited availability of suitable water for curing and/or rapid loss of curing water by evaporation. For many years self-curing admixtures were recommended as an alternative to water curing, however, limited studies have been conducted on their performance in hot weather conditions. In this investigation, the effects of a hot climate on the fresh and hardened properties of self-curing (SC) concrete and normal conventional concrete (NC) in hot weather were studied. A water-soluble polymer self-curing agent, polyethylene glycol (PEG 400), was added to the SC mixes. The testing parameters were concrete dry materials (25 or 50 degrees C) and/or mix water temperatures (5, 20 or 35 degrees C) at the time of mixing. NC samples were continuously water cured at 25 or 50 degrees C, whereas the SC ones were air cured at the same temperatures. The tested properties were workability, compressive strength, splitting tensile strength, and flexural strength. It was found that SC outperformed NC under varying conditions. The results could not be simply attributed to the retention of mix water by the self-curing admixture. A more comprehensive explanation for the observations is proposed. (C) 2020 Elsevier Ltd. All rights reserved.