Evaluating the Performance of Phase Change Materials in Alkali-Activated Materials

The high energy consumption for buildings pursues researchers to examine various potentials to improve energy efficiency for construction materials. Among various potentials, the use of phase change materials (PCMs) demonstrated a high ability to modulate the inside temperature of the buildings. These materials can absorb and release the heat in a specific temperature range regulating thermal performance for mortars and concrete. However, the performance of PCMs, including stability and heat storage efficiency in non-cementitious mixtures such as alkali-activated materials (AAMs), is still questionable. Hence, this study evaluates the performance of micro-encapsulated paraffin, as an organic phase change material, in alkali-activated materials through various tests. Results showed that the high alkalinity of the used alkali activator did not significantly affect the performance and the stability of the micro-encapsulated PCMs. A slight reduction in the mechanical performance of the alkali-activated materials due to the addition of PCMs compared to cement-based mixtures was reported. This study can help the in situ engineers choose the proper mixture for environmental and mechanical performance.