Performance Assessment of Cool Pavements Embedded With Phase Change Materials

Abstract

Higher pavement temperature leads to Urban Heat Island (UHI) and various thermal distresses in pavements. Incorporating Phase Change Materials (PCM) in pavements to regulate the temperature is an emerging area of research. The PCMs incorporated in pavements can absorb the heat energy and store it as latent heat, resulting in a reduction in pavement temperature. However, the PCMs adversely affect the desirable properties of asphalt and concrete, and hence, they are usually provided in encapsulated form. In this work, suitable PCMs and their encapsulation methods for application in concrete and asphalt pavements in Indian climatic conditions are presented. Commercially available organic PCMs, Organic Mixture 35 (OM 35) and Organic Mixture 42 (OM 42), were used in this study. Shape stabilization and core-shell encapsulation methods were adopted to incorporate the PCM in concrete and asphalt pavements respectively. Maximum reduction in concrete pavement surface temperature of 3.98 and#8451; and 4.12 and#8451; was recorded with OM 35 and OM 42 incorporation, respectively. In asphalt pavements, a peak reduction of 3.05 and#8451; and 4.36 and#8451; in the pavement surface temperature was observed using OM 35 and OM 42, respectively. Further, numerical models were developed to analyse the thermal performance and phase change process of these PCM incorporated pavements. The results of the numerical analysis indicate that the cooling potential of both concrete and asphalt pavements increases with an increase in the thermal conductivity of the pavements. In the case of shape stabilised PCMs, the cooling potential increased with the increase in porosity of the medium. Results of the long-term thermal analysis indicate that the phase change temperature determines the season of occurrence of peak temperature reduction, and the latent heat influences the magnitude of the reduction in pavement surface temperature.