Capsulated phase-change materials containing paraffin core/polymethyl methacrylate shell: Thermoregulation modifier for asphalt binder

Abstract

The paraffin/polymethyl methacrylate capsulated phase-change material (CPCM) with 55–56 °C phase transition temperature was synthesized via in-situ polymerization, and its applicability in asphalt binder was investigated by conducting various experiments. The CPCM possesses spheric morphology, with an initial decomposition temperature as high as 185.2 °C, with melting enthalpy of 128.13 J·g−1, exhibiting remarkable thermal stability. Therefore, the thermoregulation efficiency of CPCM for asphalt and the impact of CPCM on the physical properties, storage stability and rheological performance of asphalt binder were further investigated. The thermoregulation result shows that the maximum temperature difference between matrix asphalt and modified asphalt can reach 7.5 °C during the heating process. The heating rate of modified asphalt remarkably reduced at the temperature range of 47–55 °C due to the phase transition of CPCM. Additionally, the addition of CPCM slightly affected the softening point and penetration of asphalt while reducing the low-temperature ductility and viscosity. Furthermore, the softening point difference and rheological segregation index can be reached at 1.7 and 1.43, respectively, when the content of CPCM was 9 %, indicating poor compatibility between CPCM and matrix asphalt. Dynamic shear rheometer (DSR) results reveal that the addition of CPCM increased the elastic components in asphalt. Besides, the G*/sin δ of all the modified asphalt was higher than matrix asphalt during the phase transition temperature range, demonstrating the dramatic improvement in the rutting resistance of the asphalt binder.