Thermal performance of gypsum plasters with paraffin–expanded vermiculite coated by composite cementitious materials for building temperature management

The reliance of the construction sector on conventional energy sources could be considerably reduced by optimising the utilisation of solar energy. Herein, an innovative gypsum-based composite incorporating a paraffin–expanded vermiculite phase-change material (PEVPCM) encapsulated with a composite cementitious material (CCM) was developed to address the persistent leakage challenges associated with phase-change materials (PCMs). The experimental results demonstrated that the integration of CCM into gypsum plaster enhanced the thermal energy–storage capacity and stability as well as mechanical properties of the resulting PEVPCM–gypsum composite. The CCM, comprising sulfoaluminate and calcium dialuminate, generated ettringite as its primary hydration product, enhancing the structural reinforcement and leakage mitigation in the composite system. The volume stability of the gypsum plaster was superior to that of an ordinary gypsum plaster, with a 44 % lower dimensional-change rate (0.05 % vs. 0.09 %). The melting and freezing latent heat of the considered gypsum plaster were 13.56 J/g and 12.71 J/g, respectively. Furthermore, the application of this advanced plaster reduced the room temperature by 0.5–1.5 °C, while temperature fluctuations in the test environment were approximately 2 °C, demonstrating its dual functionality in improving thermal comfort in living environments and reducing building energy consumption through passive thermal regulation. These findings underscore the material potential to be used in sustainable construction practices by enhancing the energy efficiency and structural durability of buildings.