Understanding the compressive strength degradation mechanism of cement-paste incorporating phase change material

Abstract

This study aims to elucidate the effect of different mixing speeds on microencapsulated phase change material (mPCM) and examine the associated degradation mechanism of compressive strength of cement-paste. Experimental results showed that moderate to high mixing speed led to the damage of mPCM particles and consequently the PCM leakage. The PCM leakage was evidenced by changes in the rheological properties of the mPCM-pastes. The early age compressive strength seemed to be more sensitive to the PCM leakage than the 28-day compressive strength. The XRD results showed no evidence of any chemical change in the mPCM-paste associated with this leakage. Therefore, the lowered compressive strength in mPCM-paste was mainly ascribed to the decrease in the heat of hydration along with a significant increase in porosity and coarsening of pore structure.