Performance enhancement of cement mortar with superabsorbent polymer composite internally embedded with porous ceramsite sand

Abstract

Superabsorbent polymer (SAP), which can act as water reservoir, was an internal curing (IC) agent with great potential to reduce the shrinkage and cracking of cement-based materials. However, the volume shrinkage of SAP after water release will lead to the formation of additional voids, which will lead to a clear reduction of mechanical properties. In present work, a novel SAP composite with a rigid skeleton (IP-PS) was synthesized by embedding in-situ polymerized SAP hydrogel into the pores of porous ceramic (PS). The results demonstrated that the compressive strength of IP-PS0.054 was above 10 % higher than that of SAP0.054 in the early and late stages, the compressive strength of IP-PS0.054 at 28 days reached 97.71 % of that of the control group, which was predominantly ascribed to the support provided by the embedded skeleton. The development of self-desiccation was also notably delayed by the incorporation of IP-PS, as evidenced by the approximately 12 % reduction compared to SAP0.054 and 47 % reduction compared to Control group in 7-day autogenous shrinkage, which was on account of the enhanced water storage and durable IC capacity of IP-PS. Furthermore, the impermeability of cement-based materials was also improved by the in-situ polymerized hydrogel modification.