Preparation and performance evaluation of phase-change microcapsules and performance analysis of phase change asphalt.

In this study, the impact of phase-change microcapsules (PCM) on asphalt performance was investigated through a series of orthogonal experiments. These experiments focus on the evaluation of the effect of the urea-formaldehyde (melamine-urea-formaldehyde) resin as a shell material and w-tetradecane as a core material on the synthetic efficiency of PCM. The optimal preparation process for PCM was analyzed. Differential scanning calorimetry and dynamic shear rheology were employed to assess the performance of the PCM-modified asphalt (referring to as phase change bitumen). The findings indicated that the most effective synthetic parameters were determined for PCM at an emulsifier concentration of 7 wt. %, an emulsification speed of 2 000 r/min, a mass ratio of core to wall material of 1:1, a 1: 7 oil-to-water volume ratio, a synthetic time of 90 min, and a reaction temperature of 80 °C. Under such conditions, PCM exhibited a latent heat of 117 J/g. Furthermore, the microcapsule shell presented excellent sealing properties, ensuring the stability of asphalt within the range required for construction temperature. The PCM-modified asphalt showed an exothermic interval from -7. 1 to -17. 9 °C and an endothermic interval from 2. 3 to 13. 5 °C. The PCM-modified asphalt presented a phase-change enthalpy of 5. 1 J/g at a microcapsule concentration of 7 wt. %. More importantly, the incorporation of PCM effectively slowed down the hardening process of the PCM-modified asphalt and maintained its stability at room temperature. The developed phase-change asphalt exhibits great potential for application. [ABSTRACT FROM AUTHOR]