Effect of Internal Curing with Super-absorbent Polymer on the Surface Hardness of Normal Strength Concrete

The traditional curing methods for concrete might be difficult for reinforced concrete tall building and some dangerous parts. Thus, using internal curing methods with different agents which exposed to be a perfect method to reduce risk for labors and reduce the difficulty of curing. Even though, the internal curing has a positive impact on the mechanical properties, such as compressive and tensile strengths, the hardness of the concrete cured with internal curing agents encounter an issue due to leaving voids in concrete. This investigation highlights the influence of super absorbent polymer on the surface hardness and void content in the normal strength concrete. As a result, it was found that the surface hardness of the concrete improves up to 19% due to inclusion of 0.08% of super absorbent polymer to cement ratio. However, the velocity of passing wave through concrete via ultra-pulse velocity device was reduced due to increasing the length of path of the wave from separating voids in the concrete.