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Abstract: The incorporation of phase change materials (PCMs) into concrete bridge decks shows promise as a method of decreasing freeze/thaw cycling in bridge decks. The authors have conducted a study to determine the best carrier to be used for the incorporation of PCMs into concrete, as well as the effects of the incorporation of the carriers and PCMs on strength and thermal properties of mortars. Four different PCMs (PCM6, PT4, PEG400, and PEG600) were combined with two different light weight aggregates (LWAs, expanded clay and naturally porous Greek pumice) by soaking the aggregates in the liquid PCMs. The ability of each PCM to impregnate the LWAs was investigated to determine which LWA is the best carrier for the PCMs. 11 mortars in total were tested, including 3 controls (one of pure concrete, and two containing concrete and one of the LWAs) and it was determined that all of the compressive strength decreased for each of the mortars containing LWA; however, this decrease was only significant enough as to limit practical applications for mortars containing LWA and PEG based PCMs. It was found that the highest thermal conductivity of the mortars was observed for the control containing only concrete, and the lowest thermal conductivity was observed in the mortars containing pumice and PT4. The results of the tests performed were used to refine a previously developed model for the determination of the service life of concrete mixtures containing PCMs. 

Reference: Construction and Building Materials, 35 (2012) 483-490

DOI: 10.1016/j.conbuildmat.2012.04.042