Thermal Performance Evaluation of PCM-Impregnated Aggregates in Hot Mix Asphalt: Mitigating Urban Heat Island Effects

Abstract

The Urban Heat Island (UHI) phenomenon, in which the temperature in urban regions is higher relative to that in surrounding rural areas, is primarily attributed to human activities and urban development. This temperature escalation poses various challenges, impacting energy consumption, human well-being, and the overall urban environment. This study explores the potential of phase change materials (PCMs) as an addition to asphaltic mixes in alleviating the UHI effect. PCMs can store and release thermal energy through phase transition and exhibit valuable thermal properties for temperature management. In the context of UHI, PCMs play a pivotal role in alleviating the surplus heat amassed in urban areas. This study evaluates the effectiveness of shape-stabilized PCM-impregnated aggregates to reduce pavement temperature. The mechanical and thermal performance of the four different bituminous mixes has been evaluated in this study. A decrease in marshall stability while an increase in marshall flow has been observed with the increase in the proportion of PCM-impregnated aggregates in the mix. Based on the thermal analysis of PCM-modified mixes, a temperature drop of 5.03 °C and 2.9 °C in core temperature was observed in the case of 70% and 35% replacement with PCM-impregnated aggregates. The introduction of PCM-impregnated aggregates into the mix lowers the rate of increase and decrease in temperature of the asphaltic mix in direct sunlight. Electrical resistivity increased by around 4% and 8.6% for 35% and 70% replacement as compared to control sample.