Multi-scale analysis of mechanical and thermal behaviour of mortars incorporating phase change materials

Abstract

This study presents the influence of phase change materials (PCMs) on the cyclic behaviour of mortars. A multi-scale analysis comprising mechanical and thermal tests was used to explain the phenomena involved. Mechanical and thermal cyclic tests were performed on four configurations of mortars containing 0%, 5%, 8%, and 10% of PCMs. It was revealed that mechanical cyclic loading did not significantly affect the resistance of mortars contrary to thermal solicitations. Indeed, it was shown that the incorporation of PCMs improved the thermal capacity of the mortars. However, severe degradation of the heat capacity and enthalpy was noticed after the temperature cycles. The physicochemical characterisation tests confirmed a moderate structural degradation, which primarily occurred in the initial cycles. Regarding the thermal cycles, scanning electron microscopy (SEM) and calorimetry characterisations corroborated the leakage of PCMs into the cement matrix, which was responsible for the degradation of latent heat. Finally, it was observed that the PCM–mortars resisted mechanical cyclic solicitations, at least up to 1000 cycles; however, they were still sensitive to repeated variations in temperature.

Keywords:

• Mortar
• phase change materials
• cyclic behaviour
• thermal performance
• multi-scale analysis
• scanning electron microscopy
• porosity
• differential scanning calorimetry

Acknowledgements

The authors would also like to acknowledge the technical staff, who participated in this work.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by SCUSI of Rhône-Alpes and the Auvergne region, which financed this study.