Morphology changes of polymer solid-solid phase change material in high-viscosity modified asphalt (HVMA) and its influence on the properties of HVMA

Abstract

Asphalt pavement has excellent performance, but the asphalt binder is a temperature-sensitive material, which not only easily causes high-temperature distress, but also exacerbates the “urban heat island effect”. One possible method to solve this problem is to use phase change material (PCM) in the asphalt mixture, in which polymer solid-solid phase change material (PSSPCM) is one of widely used PCM. If the PSSPCM can be used in high-viscosity modified asphalt (HVMA), the high-performance modified asphalt with temperature regulation function can be obtained. However, the morphology of PSSPCM may change under the high mixing temperature of HVMA, which may also influence the properties of PSSPCM/HVMA composite. This paper selected one typical PSSPCM to investigate the morphology changes of solid-solid phase change material in HVMA and its influence on the properties of HVMA. The change of morphological and thermal property of PSSPCM in the high-temperature preparation were characterized by scanning calorimeter tests, thermogravimetric tests and heating tests, the physical, rheological and temperature regulation properties of PSSPCM/HVMA were also investigated. Test result shows that, the PSSPCM melted in HVMA at high mixing temperatures condition. However, when added in smaller contents of PSSPCM, the melted PSSPCM could uniformly distribute in the HVMA and the polymer network structure was formed. The melted and distributed PSSPCM in HVMA still had favorable temperature regulation function. The temperature regulation range of PSSPCM during the heating process and cooling process is maximum 3.8°C and 2.9°C respectively. Notably, the PSSPCM/HVMA has great high-temperature properties and favorable low-temperature properties. This study has reference value for developing the high-performance modified asphalt with temperature regulation function.