Optimizing microencapsulated PCM ratios of sustainable cement mortar for energy savings in buildings

Energy efficiency improvement techniques for buildings are among the fundamental challenges to sustainable buildings. PCMs incorporation in mortar is one of the efficient techniques for improving the energy efficiency of buildings. However, the low integration ratio of PCMs into cement mortar significantly decreases its effectiveness. Using PCMs as a replacement for sand has a negative effect that leads to the deterioration of the mechanical properties of mortar. This study aims to extend using PCMs in mortar eco-friendly and study the impact PCMs up to 50% as additions of cement content with ceramic fine aggregate waste as a replacement for sand on thermal energy storage ability improvement and enhance its physicomechanical properties. Twelve specimens were prepared, four mixtures of mortars with 0%, 12.5%, 25%, and 50% PCMs, as additions to the cement content with 100% natural sand. Eight mixtures were prepared with different ceramic fine aggregate contents with 25%, 50%, 75%, and 100% as replacements from sand content with integrated 25% and 50% PCMs, respectively. SEM, thermal performance, and physical–mechanical characteristics of the mortar-integrated PCM were performed. The results showed no chemical interactions between the PCM and the cementitious components during hydration. The compressive strength and thermal performance results showed enhancement when using ceramic as a replacement for sand by increasing about 37.1% for compressive strength, with the decreased temperatures to 9.5 °C and phase peaks shifting ahead by 115 min for a mix of 50% PCM + 100CFA, compared to 7.0 °C with phase peaks shifting by 85 min for a mix of 50 %PCM + 100NS.