Photocurable resin as rapid in-situ protective coating for slag concrete against dry shrinkage

Slag concrete has the advantages of low hydration heat evolution and a low carbon footprint, but the impact of drying shrinkage will increase the risk of cracking concrete components. To achieve low-cracking performance, dry shrinkage was prevented against water evaporation by an in-situ coating of the concrete with a photocurable resin. In this study, polyurethane-acrylic resin was applied as an in-situ coating on the surface of slag concrete by UV polymerization for the first time. The purpose of the experiment is to explore the feasibility of using photocurable resin as a surface protective coating for general construction. The experimental results show that the drying shrinkage percentage of slag concrete samples after 28 days is reduced by 40%, the compressive strength of the test block increases by 1.67 times, and the tensile strength increases by 1.8 times. The photocurable resin in-situ protective coating can adhere tightly to the surface of the substrate, inhibiting water evaporation in the sample, and providing a moist internal curing environment that effectively alleviates shrinkage. Crack propagation on the concrete surface was also greatly prevented, resulting in a more deviated crack propagation behavior; therefore, the ductility of slag concrete is improved.