Investigating the effects of using seawater and superabsorbent polymers on the internal curing of self-compacting concrete

Internal Curing in recent years is one of the special topics in achieving optimal mechanical properties and durability in self-compacting concrete. The use of superabsorbent polymers with the ability to absorb and release water in the hydration process in internal curing has fewer performance limitations. Due to environmental considerations and the lack of drinking water in the world, the use of seawater in construction, including concrete Structures and curing of bulk, high-performance and self-compacting concrete has been the subject of recent research. The present study investigates the effect of using superabsorbent polymers and seawater in the internal curing of self-compacting concrete. Two types of superabsorbent polymers with two different amounts have been used in this research. In order to evaluate the mechanical properties and durability of internally cured concrete samples, compressive strength, electrical resistance, water penetration under pressure, freeze-thaw cycles, and microstructure tests were used in this research. The results showed that the compressive strength of samples made and cured with seawater and superabsorbent polymers increased by over 10%. Examining the results of the electrical resistance test on the samples cured using potassium-based super absorbent polymers also shows the greater effect of internal curing in the process of obtaining resistance and completing the hydration. The increase in electrical resistance as a result of internal curing using potassium-based superabsorbent polymer with amounts of 0.2% and 0.3%, compared to sodium, was 25.5% and 19.9%. Internal curing using seawater and potassium-based superabsorbent polymer caused a reduction of over 40% in the test of water penetration compared to sodium-based superabsorbent polymer. Investigation of microstructure results obtained from SEM, XRF, and XRD experiments, showed an increase of 8.1% and 6.2% in final products of the hydration process when using potassium-based superabsorbent polymer.