Thermal and structural behavior of thermal inertia-reinforced mortars for building envelope applications

Abstract

Phase-change materials (PCM) are applicable to various building components and systems. In this study, a thermal storage mortar is manufactured by mixing thermal storage aggregate (TSAs) synthesized using a vacuum-impregnating PCM with blast furnace slag. In the scanning electron microscopy analysis, the TSAs were mixed and dispersed relatively uniformly in the thermal storage mortar and maintained their physical shape. From the differential scanning calorimetry result, the theoretical latent heat amounts of the thermal storage mortar mixed with 10, 20, and 30 wt% TSA were 3.27, 6.21, and 8.86 J/g for both heating and cooling, respectively. The cumulative specific heat of the thermal storage mortar was 160.95 J/g when the temperature increased from 0 °C to 80 °C. Results of the thermal conductivity analysis showed that when the TSA content for the thermal storage mortar increased to 20 wt%, the thermal conductivity increased because of the effect of blast furnace slag. In the structural analysis, the reference mortar and the thermal storage mortar containing 10 wt% TSAs exhibited brittle fracture, whereas the thermal storage mortar containing 20 or 30 wt% TSA showed ductile fracture. Results of the dynamic heat transfer analysis showed that the upper and lower surfaces of the thermal storage mortar indicated a peak temperature reduction and time lag in the phase-change temperature range during heating and free cooling.