An Experimental Study On The Temperature Control And Road Performance Of PEG Cenosphere Phase Change Energy Storage Asphalt Mixture In Northwest Large Temperature Difference Area

Asphalt pavement is the most commonly used surface material for urban roads and expressways in China.However,the phenomenon of heat absorption is very significant in summer high temperature weather.Various high temperature diseases caused by traffic load seriously affect the service life of pavement and road traffic safety.The commonly used methods such as blending fiber and modified asphalt can alleviate the high temperature disease to a certain extent,but can not fundamentally solve the temperature sensitive property of asphalt pavement.In the northwest region with large temperature difference,the temperature difference between day and night is large,and the high temperature duration is short.In the latent heat stage of phase change,phase change materials(PCMs)can store /release a lot of heat without obvious change of its own temperature.To make the PCMs in the latent heat stage of phase change during the short period of high temperature,this characteristic is applied to asphalt pavement in Northwest large temperature difference area.In this way,it’s high temperature damage can be effectively reduced.Fly ash cenosphere is a kind of hollow bead material with high strength,wear resistance and high temperature resistance,which can be used as the adsorption carrier of PCMs.Based on the characteristics of PCMs,fly ash cenosphere is used as the shell of microcapsule.Then fly ash cenosphere phase change microcapsule is prepared by the way of fly ash adsorption wrapping PCMs.It is added to the asphalt mixture to adjust the temperature of the asphalt pavement.Then can get the phase change asphalt concrete with the performance of active temperature control,which can satisfy the basic road performance.Finally,it can be applied to asphalt pavement to absorb heat in a short period of high temperature and reduce the peak temperature of pavement.The main contents of this paper are as follows:(1)Polyethylene glycol(PEG)was used as phase change material,and fly ash cenosphere was used as microcapsule shell.PEG cenosphere phase change microcapsule was prepared by vacuum loading.Then a large number of PEG cenosphere phase change microcapsules were prepared,which were used to study the road performance and temperature control effect of phase change asphalt mixture.(2)By replacing fine aggregate with equal volume(the substitution amount is 20%,40%and 60%),PEG cenosphere phase change microcapsules are added into Superpave Asphalt Mixture(Sup-13,Sup-20).Combined with the specification and actual engineering test,the road performance of two kinds of phase change asphalt mixture with different content is tested.The results show that with the increase of PEG cenosphere phase change microcapsules content in asphalt mixture,the pavement performance of asphalt mixture is improved obviously.With the increase of content,the dynamic stability increased,and the Marshall stability decreased gradually,the maximum flexural strain decreased slightly.With the increase of asphalt content,at first,Marshall residual stability and freeze-thaw splitting tensile strength ratio of the two types of asphalt mixture increase,and then decrease.With the maximum content of 60%,all performance indexes of asphalt mixture meet the specification requirements.(3)Through the preparation of different contents of the middle and upper layer of the rutting plate specimens,the combination of rutting plate temperature specimens.PEG cenosphere phase change microcapsules were mixed into the middle and upper layers of the actual asphalt pavement.Through indoor simulation test and outdoor simulation test,the temperature control effect of different dosage combinations of rut plate temperature pieces was analyzed and compared.In the indoor simulation test,it is found that with the increase of PEG cenosphere phase change microcapsules content,the cooling effect of the rutting board temperature measurement specimen is more and more obvious.The middle and upper layers are the highest content groups,and the temperature decreases by 4.2 ℃,5.7 ℃ and 2.6 ℃at the depth of 2cm,5cm and 8cm respectively.In the indoor simulation test,the temperature decreases by 4.1 ℃ at the depth of 2cm.The results show that PEG cenosphere phase change microcapsules can play a significant role in adjusting the temperature of asphalt mixture and reduce the high temperature peak value of the mixture.