Preparation of polyurethane solid-solid low temperature PCMs granular asphalt mixes and study of phase change temperature control behavior

Abstract

In order to slow down the cooling rate of mixture and reduce the low-temperature cracking of asphalt pavement in large temperature difference areas, polyurethane solid–solid low-temperature phase change materials (PSLPCMs) were prepared by prepolymer method in this study. The PSLPCMs were incorporated into hot mix asphalt mixture to prepare PSLPCMs particle asphalt mixture. The pavement performance and phase change temperature control behavior of this special type of mixture were analyzed from the perspectives of particle content and particle size. Studies have shown that PSLPCMs have good phase change thermal storage performance and thermal stability. Different PSLPCMs content and particle size have certain improvement effect on the high temperature stability and low temperature crack resistance of the mixture, and have no obvious adverse effect on the water stability of the mixture. At the same dosage, with the increase of particle size, the improvement effect of PSLPCMs particles on the road performance of the mixture is more obvious. With the increase of PSLPCMs particle content, the specific heat capacity of asphalt mixture increases, and the thermal conductivity decreases. The temperature regulation effect of asphalt mixture shows an increasing trend, and the cooling rate slows down. The PSLPCMs particles with particle size of 1.18–2.36 mm have better improvement effect on the temperature regulation performance of the mixture. When the content of PSLPCMs is 7 wt%, the maximum temperature regulation effect of the mixture reaches 3.4 °C.