Superabsorbent Polymers for Internally Cured Concrete

Two commercial superabsorbent polymer (SAP) formulations were used to internally cure cement pastes, mortars, and concretes with a range of water-to-cement ratios (w/c 0.35–0.52). The following properties were determined as a function of cement chemistry and type, use of chemical admixtures, use of slag, and batching parameters: SAP absorption capacity, fresh mixture workability and consistency, degree of hydration, volumetric stability, cracking tendency, compressive and flexural strength, and pumpability. SAP internal curing agents resulted in cementitious mixtures with improved hydration, accelerated strength gain, greater volumetric stability, and improved cracking resistance while maintaining sufficient workability to be pumped and placed without sacrificing compressive or flexural strength. When using SAP, batching adjustments prioritized the use of water reducing admixture instead of extra water to tune workability. While the benefits of SAP internal curing agents for low w/c mixtures were expected, SAP-containing mixtures with w/c ≥ 0.42 displayed accelerated strength development and decreased cracking tendency.