Enhance Fire Endurance of PCM Embedded Energy-Efficient Concrete Using Melamine Formaldehyde Encapsulation

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.