Heating and cooling systems are a major contributor to global energy consumption and CO2 emissions in the construction industry. In case of restoration of historical buildings, a possible solution to mitigate this problem is to incorporate thermal energy storage systems, like phase change materials (PCMs), into restoration mortars. PCMs, like poly-ethylene glycol (PEG), can be incorporated in lime-based mortars as bi-phased smart aggregates. These aggregates consist of a porous inert matrix, for instance small flakes of Lecce Stone, containing the active PEG phase [1]. Although mortars with PCM show favourable thermal properties, nevertheless they present a reduction in their mechanical resistance possibly due to: (i) a lack of compatibility between aggregate and binder; (ii) a lack of confinement of the PEG polymer in the stone, causing its dispersion in the mortar. Therefore, the aim of this study was to investigate the causes of the observed reductions in mechanical properties and to propose a method to prevent this occurrence. The results showed that the dispersion of PEG-1000 within the binder is apparently the main reason behind the reduction of the mechanical properties. Micro-FTIR compositional mapping evidenced that the lack of confinement of the PEG-1000 in the inert aggregates results in its dispersion inside the mortar; mechanical tests showed that the binder’s mechanical resistance is reduced in the presence of PEG. To prevent PEG dispersion, a simple coating procedure of the smart aggregates was successfully implemented. The improved confinement of the PEG-1000 in the inert aggregates produced a reduction of the internal cracks and pores of the mortar.
Prevention of PEG-1000 Migration in Eco-Sustainable, Form-Stable Phase Change Material Included in Aerial Lime-Based Mortars
Frigione M.;Sarcinella A.;
2025-01-01
Abstract
Heating and cooling systems are a major contributor to global energy consumption and CO2 emissions in the construction industry. In case of restoration of historical buildings, a possible solution to mitigate this problem is to incorporate thermal energy storage systems, like phase change materials (PCMs), into restoration mortars. PCMs, like poly-ethylene glycol (PEG), can be incorporated in lime-based mortars as bi-phased smart aggregates. These aggregates consist of a porous inert matrix, for instance small flakes of Lecce Stone, containing the active PEG phase [1]. Although mortars with PCM show favourable thermal properties, nevertheless they present a reduction in their mechanical resistance possibly due to: (i) a lack of compatibility between aggregate and binder; (ii) a lack of confinement of the PEG polymer in the stone, causing its dispersion in the mortar. Therefore, the aim of this study was to investigate the causes of the observed reductions in mechanical properties and to propose a method to prevent this occurrence. The results showed that the dispersion of PEG-1000 within the binder is apparently the main reason behind the reduction of the mechanical properties. Micro-FTIR compositional mapping evidenced that the lack of confinement of the PEG-1000 in the inert aggregates results in its dispersion inside the mortar; mechanical tests showed that the binder’s mechanical resistance is reduced in the presence of PEG. To prevent PEG dispersion, a simple coating procedure of the smart aggregates was successfully implemented. The improved confinement of the PEG-1000 in the inert aggregates produced a reduction of the internal cracks and pores of the mortar.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
