Shielding Encapsulation to Enhance Fire Endurance of Phase Change Materials in Energy-Efficient Concrete

Phase change materials (PCMs) are latent heat storage materials that can store a large amount of thermal energy while changing their phase and are usually incorporated into concrete for improving thermal properties. However, the fire performance of concrete incorporated with PCMs is adversely affected at elevated temperatures as PCMs have weaker fire endurance and burn out instantly in case of fire exposure. This research is focused on improving the fire endurance of PCMs introduced into the lightweight aggregate (LWA) using the vacuum infusion technique and incorporated in concrete encapsulated with fire resistant coating materials to achieve energy efficiency. In two encapsulation layers, the first encapsulation of epoxy sealed paraffin inside the pores of LWA at ambient conditions, while the second melamine-formaldehyde layer prevented the leakage of PCM into the concrete matrix at elevated temperatures and consequently shielded the flammable reaction of PCM. By shielding PCM, the fire performance of concrete was improved, as PCM inside concrete effectively remained serviceable up to 250 degrees C temperature.