Preparation Of Phase Change Asphalt Mixture And Its Controling Temperature Mechanism

Because of big blackness and strong heat absorption capacity, bitumenconcrete pavement is easy to get high temperature rutting and related diseases.According to statistics, more than80%of maintenance and repair costs is used indiseases such as high temperature rutting at home or abroad every year, lots ofmanpower, material and financial resources is waste. Some technologies of bitumenconcrete pavement such as modifying asphalt, adding fiber, opt imized mineral gradecomposing were adopted to thermal environment and overloading, but effect waslimited. besides, paving area of bitumen concrete pavement is wide, urban heatisland effect is intensifiered. Therefore, the study is from perspective ofthermoregulation asphalt mixture temperature field actively, phase change principle,heat resistant of material, rheological property and modification mechanism ofphase change asphalt, phase change materials import encapsulation process andphase change asphalt mixture effect and mechanism of thermal regulating,foundation of phase change asphalt mixture engineering application was made.Eutectic phase change theory prediction model was established, phase changetemperature and phase change latent heat were predicted by the model, binary phasediagram was mapped by cooling curve method and phase change theory model wasverified, the models predicted reliable.Technical standard of road phase change materials was came up with and phasechange materials were screened, DSC, TG and FTIR were used to analysisthermostability of phase change materials, heat resistance of PEG was good.Three indicators of different proportion phase change asphalt were tested,effect of PEG400020%dosage on asphalt is smallest. In the view of phase changeproperties, DHR was used to analysis the high temperature, low temperature andfatigue performance of phase change asphalt, rheological property effect was moreor less of phase change asphalt. modification mechanism of phase change asphaltwas studied by FTIR and fluorescence microscopy, the result showsed that chemicalchanges of phase change asphalt and phase change particle was Uneven microngrade distribution in asphalt.Pore structure of ceramsite was characterized by mercury injection method, and C3and C5ceramsite were screened, effect of phase change material importingwas characterized by X-ray CT，import rate of phase change materials was32%~42%, import effect is good, Curing epoxy encapsulation process which was based onhigh temperature vacuum import was came up with,glass-transition temperature Tgand hardness as evaluation index, epoxy encapsulation layer performance was good,composite phase change aggregate were made by the curing epoxy encapsulationprocess, thermophysical property, phase change stability and heat resistance ofcomposite phase change aggregate were analysised, and the three performance weregood.Phase change asphalt mixture was prepared, thermal diffusion coefficient and specific heat capacity C were tested by transient planar heat source method (HotDisk), unsteady heat conduction method and specific heat transient indirectmeasurement method, wave increases of C and trough decreases of was the keyof phase change temperature in the phase change temperature. thermal environmentof asphalt concrete pavement was analyzed and sunlight temperature control boxwas made， tests of phase change asphalt mixture specimen were made, it’sthermoregulation effect was tested by temperature monitor system. Results showsthat comparing to asphalt mixture, phase change asphalt mixture can reduce thetemperature by8to10℃and it has a good effect on adjusting the roadtemperature. Road performance of phase change asphalt mixture was verified, roadperformance of directly incorporating phase change asphalt mixture was a littlelower with increase of dosage but they were still meet specification requirements,water stability was not meet the specification requirements, road performance ofphase change asphalt mixture of incorporating composite phase change material wasgood.