Aging-Related Cooling Performance Evaluation and Fabrication Conditions Optimization for Alkane-Based Phase Change Microcapsule-Modified Asphalt

ABSTRACT Phase change microcapsules (PCMCs) have been developed as asphalt binder additives that can lower the peak road temperatures or extend the time it takes to reach the peak temperatures in hot summer times. However, few studies pay much attention to the possible cooling performance decline of PCMC-modified asphalt (PCMA) caused by the degradation of PCMCs during asphalt binder preparation and service processes. In this research, one type of PCMC with a phase change point of 37°C was chosen for the preparation of PCMA. The impact of PCMCs on performance grade, storage stability and cooling effects of PCMA was evaluated. The degradation of PCMCs in asphalt binder after thin-film oven tests and pressure aging vessel (PAV) aging tests was investigated from both perspectives of PCMCs and PCMA. Additionally, the optimal design and preparation conditions for PCMA were discussed based on the cooling efficiency. The results demonstrate that the introduction of PCMCs can endow asphalt with better cooling performance while not causing adverse effects on binder performance grade and storage stability. The results from morphology and enthalpy of PCMCs to rheological behavior and cooling performance of PCMA consistently illustrate the massive damage of PCMCs and cooling performance deterioration of PCMA caused by aging. Increasing the dosage of microcapsules and reducing the binder preparation temperature contribute to the sustainable cooling performance based on orthogonal experiment results.