LAUSR

Abstract This paper investigates the preparation and assessment of mortar-phase change materials (PCM) systems to gain a full understanding of using the heat stored in PCMs to delay or prevent ice formation in concrete. Desirable PCMs and light weight aggregates (LWA), which act as carriers of the PCMs, were first selected based on their thermal and physical properties. LWAs containing PCMs were prepared and assessed for different combinations of materials. Cyclic freeze-thaw mass loss, latent heat attenuation, and FTIR tests were conducted to characterize the stabilities of the LWA-PCMs. The thermal performances of the mortars containing LWA-PCMs were investigated using a longitudinal guarded comparative calorimeter (LGCC) that was operated under quasi-steady state conditions during the cooling/heating process. The results confirmed that PCMs can be steadily absorbed in LWAs without chemical reactions or great losses in latent heat when the LWA-PCMs were coated in a certain way. Cement paste was recommended to coat the surface of the LWA-PCMs for better compatibility with the system than that of traditional coating materials. The ability of the PCM to delay or prevent ice formation in mortar was verified from the exothermic/endothermic events associated with the phase transformations of the pore solution and PCM. In the present study, when up to 50% vol. of the LWA was replaced as carriers of PCM, the heat released by the PCM was sufficiently high to inhibit ice formation.