Experimental Research Of Porous Composite Phase Change Materials Used To Cool Asphalt Pavement By Heat Storage

Owing to its high solar absorptivity,in summer,asphalt pavement tends to absorb heat and its temperature tend to increase.On the one hand,it will cause rutting distress of asphalt pavement,then decrease its service life;on the other hand,as a heat resource,asphalt pavement was being baked and the urban heat island effect would be aggravated.In view of these,supported by National Natural Science Foundation[2],on the purpose of relieving the part of the urban heat island effect caused by asphalt pavement and to prolong the service life asphalt pavement,this paper attempt to explore decrease the temperature of asphalt pavement through utilizing phase change heat storage materials.First of all,on the basis of reviewing research efforts on phase change materials both domestic and abroad,to find a phase change material which is applicable to the practical requirement of asphalt pavement,according to four principles,forms of phase change,temperature of phase change,degree of supercooling and phase separation,high temperature performance,experiment methods such as thermoanalytical technique(DSC/TG),Fourier transform infrared spectroscopy(FT-IR)were used,eventually,polyethylene glycol 2000(PEG 2000)was selected as target phase material.Then,polyethylene glycol modified asphalt was prepared,means of water bath and sunshine bath was used to analyze heat storage efficiency of phase change modified asphalt and phase change modified asphalt mix.Thirdly,to increase amplitude of heat storage and temperature decreasing,combined with consideration of pavement construction and application requirement,epoxy resin was utilized to encapsulate PEG2000 into porous volcanic rock base to prepare phase particle capable of heat storage.Finally,by conducting Marshall stability and freeze-thaw split test,the coolly mixed heat storage asphalt mixture was evaluated.The results show that the phase change temperature of PEG2000 was about 50?,the phase change enthalpy of 188J/g,which is applicable to asphalt pavement;as a carrier,phase change materials can be effectively adsorbed and properly capsulated by porous volcanic rock;marshall stability and flow value of coolly mixed heat storage asphalt mixture could meet the specification requirements,but its water stability should be observed in further study.This study explored the phase change material used in asphalt pavement,could be referential in design and selection of phase change thermal storage of asphalt pavement.