Quantifying the water donation potential of commercial and corn starch hydrogels in a cementitious matrix

In this study, we introduce a new methodology to quantify the internal curing potential of hydrogels in a cementitious matrix. The swollen Super Absorbent Polymers (SAPs) and newly synthesized corn-starch hydrogels are investigated by embedding a capsule filled with swollen hydrogel in a cement mortar cube and monitoring the internal wetting area around the hydrogel capsule for 56 days. Our findings demonstrate that all of the investigated hydrogels serve as effective internal curing agents, releasing water in a cyclic pattern governed by the humidity gradient between the hydrogel and the surrounding matrix. Moreover, the regions around the hydrogel capsules display a denser accumulation of calcium silicate hydrate (CSH) gel, indicating improved hydration due to internal curing from the hydrogels. This research offers valuable understanding into the possibilities of utilizing bio-based materials and SAPs for internal curing and the creation of environmentally friendly cementitious materials. In summary, the proposed innovative approach serves as an effective way for measuring the internal curing capabilities of hydrogels within cementitious materials.