DEVELOPMENT AND THERMAL PERFORMANCE EVALUATION OF A PCM-ENHANCED CONCRETE PAVEMENT FOR SURFACE TEMPERATURE REDUCTION IN TROPICAL CONDITION

Abstract

The urban heat island (UHI) effect is an important environmental challenge in rapidly developing urban areas, where built surfaces can reach substantially higher temperatures than surrounding areas. Pavement materials contribute to this phenomenon by absorbing and storing solar energy during daytime exposure. This study investigates the thermal and mechanical performance of a phase change material (PCM)- enhanced concrete pavement developed to reduce pavement surface temperatures under tropical outdoor conditions. Paraffin wax was selected as the PCM because of its phase-change temperature range suitable for the experimental conditions, while expanded clay aggregate (ECA) was used as a porous carrier for PCM incorporation. Four pavement mixtures containing 0%, 3%, 6%, and 9% PCM-integrated ECA were prepared, with the PCM-containing material incorporated within the upper surface layer of the pavement specimens. The thermal performance was evaluated through outdoor monitoring over a 15-day period at one-hour intervals. Compressive strength was evaluated at 7, 14, and 28 days, while flexural strength was evaluated at 28 days. The results showed that PCM incorporation reduced the peak pavement surface temperature compared with the control specimen. The 3%, 6%, and 9% PCM mixtures reduced the peak surface temperature by approximately 3.5 °C, 6.0 °C, and 6.5 °C, respectively. Although increasing PCM content improved thermal performance, the additional reduction between 6% and 9% was relatively small. The 6% PCM mixture provided a balance between thermal performance and mechanical strength, with a reported 28-day compressive strength of 27 MPa and flexural strength of 3.12 MPa. The findings indicate that PCM-integrated concrete pavement has potential for reducing pavement surface temperatures under tropical outdoor conditions. However, further investigation is required to evaluate long-term durability, environmental implications, thermal cycling behaviour, and the potential contribution of the technology to urban-scale UHI mitigation.