Laboratory investigation of phase change effect of polyethylene glycolon on asphalt binder and mixture performance

Polyethylene glycol (PEG) has been used as a phase change material in asphalt mixture to cool asphalt pavement in summer. However, the PEG is much likely to leak and then influence its performance. This study aimed at studying the interaction between PEG and asphalt for phase change effect. Laboratory tests were conducted to evaluate the influence of PCM on asphalt/asphalt mixture performance, including microscopic test, dynamic shear rheometer test, indoor irradiation test and shear strength test. The results showed that the measured phase change enthalpy of PEG/asphalt composite was lower than theoretical results. Based on the observed FTIR spectra and fluorescence images, the PEG was found evenly distributed in the asphalt at a low content. The results of frequency and temperature sweep tests indicated that the liquid state of PEG could improve the elastic property of PAC. Furthermore, the zero shear viscosity at 40-60 degrees C and the non-recoverable compliance at 3.2 kPa and 12.8 kPa both increased due to the addition of PEG. The peak temperature of the PEG/asphalt mixture with 20% PEG was 3.3 degrees C lower than control asphalt mixture. However, the shear strength of PEG/asphalt mixture decreased by 20.3%, compared with control asphalt mixture. The study findings indicate that it is desired to propose an effective method to incorporate phase change material in asphalt mixture in order to reduce the influences of PCM leakage on performance. (C) 2019 Elsevier Ltd. All rights reserved.