Thermal Behavior of Phase Change Materials in Concrete Pavements: A Long-term Thermal Impact Analysis of Two Organic Mixtures

Elevated pavement temperature causes the urban heat island (UHI) effect as well as thermal stresses in concrete pavements. Therefore, efforts are being made since the last few decades to reduce the pavement surface temperature. Incorporating phase change materials (PCMs) in pavements to reduce the pavement surface temperature is an emerging field of research. The present study evaluates two commercially available organic mixture (OM)-based PCMs (OM35 and OM42) with an objective to reduce the pavement surface temperature. As direct inclusion of PCM adversely affects the mechanical strength of concrete, encapsulated PCMs were incorporated into the concrete pavement. While most of the earlier studies investigated the short-term thermal behavior of PCM-incorporated pavements, an effort has been made under this study to evaluate its seasonal and long-term performance. The latent heat and phase change temperature of PCM were identified as the crucial factors influencing the cooling potential of the PCM-incorporated pavements. Further, the pavement surface temperature during the night increased only to about half of the reduction in temperature during the daytime due to the slower solidification rate of the PCMs. The statistical analysis indicates that there is a significant and consistent reduction in pavement surface temperature with PCM incorporation in the long term. The maximum temperature reduction reported with PCM incorporation was 4.12 degrees C with OM42.