Core-shell PCM encapsulation model for thermoregulation of asphalt pavements

Abstract

The implementation of cooler pavements plays an important role in alleviating the urban heat island (UHI) effect and extending the lifespan of pavements. One potential approach to develop cool pavements involves the incorporation of phase change materials (PCMs). In this study, a numerical investigation is conducted to evaluate the effectiveness of incorporating core–shell encapsulated PCMs within asphalt pavements. To facilitate this analysis, an enthalpy-porosity-based heat transfer model is developed, and its accuracy is validated through experimental data obtained in-house. For this study, commercially available PCMs, namely Organic Mixture 35 (OM 35) and Organic Mixture 42 (OM 42), encapsulated within hollow steel balls are used. The outcomes of the investigation reveal that the inclusion of core–shell encapsulated PCMs is a viable method for reducing the temperature of asphalt pavements. Further, it is found that as the thermal conductivity of asphalt pavements increases from 1.21 to 2.41 W/mK, there is corresponding proportional increase in the temperature reduction achieved by integrating the PCMs with the pavements. The proportional temperature reduction with increase in thermal conductivity of asphalt pavements are found to be 3.55 °C using OM 35 and 3.37 °C using OM 42 respectively. It is worth noting that while the thermal characteristics of the steel balls exhibit a limited influence on temperature reduction, their physical attributes should be given careful consideration during the design phase of asphalt pavements.