Preparation And Research Of The Composite Shape-Stabilized Phase Change Materials Applied To Cooling Pavement

Asphalt pavement is widely used in highway engineering because of its advantages of strong load capacity,convenience in construction and maintenance,good driving comfort,low noise and renewable utilization.According to the statistics,asphalt pavement has become the main form of pavement in our paved road construction.At present,over90% of the expressway built,reconstructed or repaired has adopted asphalt pavement.However,asphalt pavement is prone to produce various thermal stability diseases at high temperature.At the same time,the volatilization of asphalt materials will release a lot of volatile matter and heat because of the high temperature,which not only pollutes the environment,but also aggravates urban heat island effect.Based on the theory of phase-change thermal storage,two kinds of composite shape-stabilized phase change materials had been prepared in this study,which can be applied to bituminous mixture to reduce the temperature of the asphalt pavement.First of all,according to the technical requirements of asphalt pavement engineering,two kinds of phase change materials,stearic acid and polyethylene glycol,are selected.In view of the occurrence of leakage of two kinds of materials in application,the inorganic carriers TAMSN and Dop-SBA-15 were used to fix stearic acid and polyethylene glycol respectively,to avoid the leakage of both phase change materials.The composite phase change materials SA/TAMSN and PEG/Dop-SBA-15 were prepared by physical adsorption.Secondly,using analysis and characterization methods,including of scanning electron microscopy(SEM),transmission electron microscopy(TEM),Fourier Transform Infrared Spectroscopy(FT-IR),X-ray diffraction(XRD),Brunner-Emmet-Teller measurements(BET),differential scanning calorimeter(DSC)and thermo gravimetric analysis(TGA),to test surface morphology,chemical composition,thermal stability,crystallization,enthalpy and phase change temperature range of the SA/TAMSN and PEG/Dop-SBA-15 composite phase change material,moreover,the optimum content of stearic acid SA/TAMSN composite phase change material is 70 wt% and the optimal content of polyethylene glycol PEG/Dop-SBA-15 composite PCM is 60 wt% through the results of leakage test.According to the other experimental results,the melting enthalpy of70 wt% SA/TAMSN is 108.8 J/g,the enthalpy of solidification is 114.1 J/g,the transformation temperature range of melting is 67.1 C,~78.0 C,and the temperature rangeof transformation is 59.5 ~64.0 ~64.0.The melting enthalpy of 60 wt% PEG/Dop-SBA-15 is 66 J/g,the setting enthalpy is 45.6 J/g,the transformation temperature range of melting is 52.4 C,~66.4 C,and the phase change temperature range of solidification is 45.8 ~28.7~28.7.Both two kinds of materials meet the technical requirements of asphalt pavement material and have good thermal properties,which makes them has good potential in application potential.In this study,not only new type of composite shape-stabilized phase change materials has been prepared to be used for cooling of asphalt pavement,but also expand the applications of phase change materials,providing the theoretical basis and technical support for the application of composite phase change asphalt materials.