Microstructure and durability characteristics of self-curing concrete

Efficient curing of concrete requires high water demand which is not available in many practical situations. Therefore, the need of self-curing concrete becomes more demanding. In this study, polyethylene glycol (PEG) and polyacrylamide (PAM) have been used as water soluble polymers to develop self-curing concrete. The main microstructural and durability characteristics of the developed self-curing concrete mixture were examined and compared to those of conventional concrete mixtures with no self-curing agents under different curing regimes. One batch of the self-curing and the conventional mixtures were left in the lab air-cured to act as non-water-cured control samples. The water curing regimes for conventional mixture included continuous moist-curing (water-immersion) for 3, 7 and 28 days and periodical moist-curing by means of wetted burlaps for 3 and 7 days. Curing regimes for the self-curing mixtures included 3 days of moist-curing and periodical curing using wetted burlaps for 3 and 7 days. The microstructure characteristics of the concrete mixtures were investigated by a scanning electron microscope. The durability performance of the concrete mixtures was evaluated by measuring the rapid chloride permeability and water permeability. Self-curing concrete mixtures showed better microstructure development and durability performance than those of the air-cured conventional concrete mixtures. A short 3 days moist-curing significantly improved the performance of the self-curing concrete mixture to a level almost similar to that of the conventional concrete mixture that was water-immersed for 28 days. Self-curing concrete represents a step towards a new construction material due to its lower water demand needed for curing, and hence can reserve the limited water resources in many parts in the world.