Snow Melting Effect And Damage Mechanism Of Phase Change Warm Mix Asphalt Mixture Under Aging Condition

The winter in northern China is long,and the ice and snow pavement always puzzles people’s travel mode.The appearance of energy-saving and environmental-friendly self-melting snow material opens up a new research direction for many scientific researchers.In order to avoid the negative impact of high temperature mixing on the environment,this paper adopts warm mixing technology,phase change material DTC are mixed into warm asphalt mixture to make phase change temperature mixing asphalt mixture.Under the condition of thermal oxygen aging and ultraviolet aging,the ice melting effect,road performance,decay law and damage mechanism of phase change warm mix asphalt mixture were studied.The main research contents and results are as follows:(1)The reaction and exothermic range of the warm mix agent and DTC were determined by infrared spectrum test and differential scanning calorimetry test.The results showed that there was no chemical reaction between the warm mix agent and DTC,and the exothermic range of DTC was from 20.6 ℃ to-20.8 ℃.(2)The indoor snow melting test and outdoor snow melting test are designed,and the snow melting effect of the test road is observed.Indoor ice and snow melting test Through self-made mold,the thickness of snow,the ambient temperature of ice and snow melting,the time of ice and snow melting,and the scheme of energy replenishment for the test pieces before ice and snow melting were designed by ourselves;the outdoor snow melting test is carried out in a few days in winter,and the samples are placed in a sunny place to simulate the real road environment,and the snow melting conditions with different snow thickness are designed;the pavement design of the test section is as follows The road with DTC is the test section,and the road without DTC is the contrast section.The results show that the snowmelt volume per unit area indoor,the icemelt volume per unit area indoor and the DTC content increase linearly with y=ax+b,and the thermal oxygen aging and ultraviolet aging have no significant effect on the snowmelt;the snowmelt volume per unit area outdoor is more significant for the snowmelt of small and medium snow;the snowmelt observation on test road shows that the pavement in the test section is 3 hours faster than that of the pavement.(3)The pavement performance of phase change temperature mix asphalt mixture is studied based on Marshall stability test,beam bending test,freeze-break test,immersed Marshall test and freeze-thaw splitting test.It is found that when the amount of DTC is increased by 1‰ the Marshall stability,bending tensile strength(-10 C),bending tensile strain(-10 C),freeze-break stress and residual stability decrease by 4.66%,3%,10%,4.39% and 1.66% respectively.The freeze-thaw splitting strength ratio reaches peaks at3‰ of DTC phase change material.Considering snow melting effect and road performance comprehensively,the amount of DTC phase change material in asphalt mixture should not be too large.It is suggested that the amount of DTC should be controlled within 3‰ of the mixture.(4)Microstructure of Phase change warm mix asphalt mixture was studied by electron microscopy and nuclear magnetic resonance(NMR).The results show that with the increase of DTC phase change material content,the roughness of specimen increases and the porosity increases.It can be seen from NMR test that the porosity of phase change warm mixing asphalt mixture increases with the increase of DTC.When the content of DTC is 0‰-4‰,the porosity of phase change warm mixing asphalt mixture is ranked from large to small as follows: short-term aging > ultraviolet aging > non-aging > long-term aging.When the content of DTC is 5‰,the ultraviolet aging porosity is slightly larger than short-term aging.