The Preparation And Study On Shape-stabilized Phase Change Materials For Road Surface Temperature Control

With the rapid development of China's transportaion,the disease problem of roads has increased dramatically throughout the country.High temperature in summer directly affects the stability of asphalt concrete pavement and causes road damage,which reduces road safety,durability and operational efficiency.Therefore,it is very important to study the high temperature stability and improvement measures of road surface.This paper summarized the common methods of road temperature control and focused on the research progress of temperature control technology by adding phase change material into asphalt concrete during construction.A shape-stabilized phase change material suitable for temperature control of asphalt concrete pavement was prepared and its feasibility was studied.The specific research contents are as follows:(1)Based on the technical requirements of road phase change temperature-controlled materials,polyethylene glycol(PEG),an organic phase change material with good heat storage performance and less undercooling during phase change,was selected as the core material of the shaped phase change material.To solve the problems of liquid flow and leakage of phase change materials,the shape-stabilized phase change material(PEG/SBA-15)was prepared for construction-friendly by introducing PEG into the matrix of onion-shaped mesoporous silica(SBA-15)by vacuum impregnation in this paper.The thermal conductivity of PEG/SBA-15 was increased to 1.3 times that of PEG,the phase transition temperature was suitable,and the phase transition enthalpy was higher(112 J/g),which could store more heat,thus improving the effect of road temperature control.(2)In order to solve the problem of low thermal conductivity of phase change materials,a novel shape-stabilized phase change material(PEG/CLMS)with improved thermal conductivity was prepared by using the carbon layer modified mesoporous silica(CLMS)as the matrix of PEG.After 100 heat cycles,the thermal properties did not change significantly.In addition,the thermal conductivity of PEG/CLMS was significantly improved,reaching 1.65 times that of PEG,which was conducive to the rapid absorption and release of concrete heat by phase change materials,so as to timely control the temperature of the pavement.(3)This paper studies the feasibility of adjusting the temperature of the prepared formalized PCM by adding it into asphalt mixture by equal volume substitution method,and the temperature by heat transfer theory calculation.The results show that when the mass fraction of the PCM mixed with asphalt concrete is 5%,the theoretical temperature control can reach 5.55?.Therefore,it has a good prospect of road temperature control and provides more choices for road temperature control materials.