Preparation and Characterization of Temperature-Adjusting Asphalt with Diatomite-Supported PEG as an Additive

To solve the rutting damage of asphaltic pavement and the adverse effects of urban heat islands, diatomite-adsorbing polyethylene glycol (PEG), that is, diatomite-supported PEG (PEG/diatomite), was synthesized as a form-stable composite phase change material (CPCM), which was used as a modifier to prepare the temperature-adjusting asphalt, which can lower the temperature of the road surface on a hot summer afternoon. The microstructure and chemical structure of CPCM were investigated using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectra. Also, effects of CPCM on the thermal properties, morphology, and rheology of modified asphalt were studied via differential scanning calorimetry (DSC), atomic force microscopy (AFM), and dynamic shear rheometer (DSR) testing. It was found that the phase change enthalpy of CPCM is approximately $9.0332\mathrm{J}/\mathrm{g}$ , which is up to 60% of the theoretical enthalpy. In the laboratory test, the highest temperature variation of the temperature-adjusting asphalt specimens was $\sim 9.0°\mathrm{C}$ , which plays an effective role in regulating pavement temperature. Small bee structures were observed on the surface of PEG/diatomite-modified asphalt and showed no obvious changes from before to after aging.