Thermal-mechanical behaviors of concrete with innovative salt hydrate PCM-based thermal energy storage aggregate

This study introduces a novel approach, called fine aggregate polymerization, for the development of a thermal energy storage aggregate (TESA) using salt hydrate phase change material. The TESA features a core-shell structure, efficient encapsulation, high latent heat, thermal stability, low supercooling, and favorable chemical compatibility. The influence of TESA volume contents and particle sizes on the mechanical properties of thermal energy storage concrete (TESC) under different thermal response conditions was investigated using response surface methodology (RSM). The results reveal that reducing the particle size of the aggregate enhances both the energy storage capacity and compressive strength of the concrete. Additionally, the addition dosage of TESA positively impacts the energy storage density but negatively affects compressive strength. The dynamic mechanical thermal analysis (DMTA) reveals a reduction in the rigidity of TESA with increasing heating temperature, resulting in a decrease in the strength of TESC. However, the compressive strength can be tailored to meet diverse building design requirements, ranging from 15 MPa to 50 MPa. Furthermore, a robust RSM model was developed to elucidate the relationship between compressive strength, TESA dosages and sizes, and thermal response conditions, with its effectiveness confirmed through the analysis of variance (ANOVA). This research provides valuable insights into the development of TESA and the thermal-mechanical behavior of TESC, facilitating the design and implementation of sustainable and efficient building systems.