Abstract:
Phase change materials (PCMs) are the latent thermal storage materials that can store a large
amount of thermal energy while changing their phase and are usually incorporated in concrete for
improving its thermal properties. However, the fire performance of concrete incorporated with
PCMs is adversely affected due to high temperatures. This research is focused on improving the
fire performance of concrete incorporated with a PCM that was intruded into the lightweight
aggregate (LWA) pores using the vacuum impregnation technique. Macro encapsulation holds the
PCM inside the LWA pores. Two encapsulation layers were coated to prevent PCM from fire. First
encapsulation of epoxy sealed the paraffin inside the pores of LWA at ambient conditions, while
the melamine-formaldehyde second layer prevented the leakage of PCM into the concrete matrix
at elevated temperatures and consequently inhibited the flammable reaction of PCM with oxygen.
The fire performance of PCM embedded concrete was assessed through its residual fracture
properties after being exposed to elevated temperatures. By retarding the flammable reaction of
PCM, the fire performance of concrete was improved and it rendered PCM inside concrete
completely functional up to 250°. Different tests were conducted which helped to evaluate the
behavior of PCM modified concrete. It was observed that single Encapsulated (SE) specimens
retain around up to 32% of their compressive strength at 200°C, while Double Encapsulated (DE)
specimens retain up to 60% of their strength by inhibiting the flammability of PCM.
