The potential of using phase change materials (PCM) in cementitious materials to miti- gate damage due to thermal loadings has been recently focus of intensive research. In the case of PCMwithtransition temperatures near to the freezing point of water, their…
The potential of using phase change materials (PCM) in cementitious materials to miti- gate damage due to thermal loadings has been recently focus of intensive research. In the case of PCMwithtransition temperatures near to the freezing point of water, their potential to delay frost in a cementitious matrix has been largely investigated through the monitoring of internal temperature changeswhenexposedtorepeatedcyclesofsubzeroandambienttemperature. Yet,theeffectofthese admixtures to prevent damage in cement-based materials has not been directly studied. In this paper, mortars cylinders of two different sizes and containing 0, 10 and 30% of PCM replacement by vol- umeofaggregatesweresubjectedtofrostsalt scaling during freeze and thaw cycles. Prior to the start of the weathering and after cycles 1, 3, 7 and 15 the cylindrical specimens were subjected to X-ray microtomographytomonitormorphologicalchangesduetofrostaction,suchaschippingandcracks. Compressive and flexural strength, coefficient of thermal expansion and apparent porosity of the un- damaged composites were also investigated. Results suggest that the improvement of frost scaling resistance of the mortars with incorporated PCM is a trade-off between resulting mechanical proper- ties, thermal volume stability and porosity of the composite, as evinced from the better performance of mortars with 10% of PCM replacement.