Defensive behaviour of building envelopes in terms of mechanical and thermal responsiveness by incorporating PCMs in cement mortar layers

This paper presents a comprehensive approach to elucidate the mechanical and thermal aspects of coating layers integrated with organic-based PCMs. In that respect, three sets of cement mortars were studied experimentally to underline the significance of PCMs proportion. From a mechanical point of view, the strength of specimens cured at 20 ◦C resulted to be superior compared to 40 ◦C, with a more evident influence for cement mortars containing PCMs. Laboratory tests on specimens subjected to 50 wetting–drying cycles demonstrated an insignificant in­ crease of the mass for coatings without PCMs and a slight increase for coatings containing PCMs. During this process, growth in strength for the base mix without PCMs and a loss in strength for mixtures with PCMs was exposed; an exponential decay relationship was noted between the compressive strength with the PCM pro­ portion. Alongside this, a transient thermal analysis was carried out to assess the effect of PCMs on the dynamic thermal parameters of coating layers. A higher proportion of PCM ingredients leads to enhanced responsiveness since the heat wave penetrating the layer is smoothen and delayed. These issues can adequately address the defensive behaviour capacity of building components, without surpassing their carrying structural stability and mechanical properties.