Effects of PVA Fibers on the Mechanical and Thermal Properties of Microencapsulated Phase Change Material Mortar

Microencapsulated phase change material (MPCM) can be used in place of sand in mortar to obtain phase change construction materials; however, this will degrade the mortar’s mechanical qualities. To address this challenge, a novel synergistic approach was proposed: phase change materials were used in mortar to enhance its thermal properties, while polyvinyl alcohol (PVA) fibers were uniquely incorporated to counteract the mechanical degradation caused by MPCM. Twenty different types of mortar were created and produced. Tests were conducted on the mortar’s micro properties, consistency, compressive strength, thermal conductivity, and specific heat capacity. The findings indicate that adding 0.4% PVA to the mortar optimally strengthened it, compensating for mechanical loss, while replacing sand with MPCM had a negative impact on consistency. The thermal conductivity of the PVA-MPCM mortar ranged from 0.75 to 1.2 W·m−1·K−1, decreasing by up to 34.45% when the MPCM substitution rate reached 4%. Furthermore, as the MPCM substitution rate rises to 4%, the peak value of specific heat capacity increased by 195.28% during the heating process, and replacing sand with MPCM had a negative impact on consistency. The thermal conductivity of the PVA-MPCM mortar ranged from 0.75 to 1.2 W·m−1·K−1, indicating that adding MPCM to the mortar had a significant impact on thermal conductivity. As the MPCM substitution rate rises, so does the peak value of specific heat capacity.