| About 75% of the roads in China suffer from the problem of snow and ice on the road surface caused by winter,and the phase-change self-melting snow technology as a new environment-friendly snow and ice removal technology can effectively solve the problem of snow and ice on the asphalt pavement.Meanwhile,because hot mixing technology has certain negative effects on the environment,economic benefits,human health and other factors,the warm mixing technology and the addition of DTC phase change material during the mixing process to make the warm mixing phase change asphalt mixture(PCWM)are adopted in this paper,and the anti-sliding effect,snow melting effect,ice melting effect and temperature regulation performance of PCWM are studied.The main research contents and results are as follows:(1)The freezing test in low temperature rain and fog environment was designed.The variation of surface friction coefficient of test specimen at low temperature-5℃ and environmental humidity of 60%,as well as the temperature changes of water accumulation on the surface of the test specimen at low temperature-5℃ and rainfall environment were analyzed.The results show that under the conditions of low temperature-5℃ and environmental humidity of 60%,the higher the DTC content,the higher the surface friction coefficient of PCWM specimens;Under low temperatures of-5℃ and rainfall conditions,PCWM can effectively delay the temperature decrease of water accumulation on the surface of the specimen.When the appearance of an overall thin ice layer is taken as the standard,the 5‰ dosage specimen can delay the freezing time by about 1h at most compared to the0‰ dosage specimen.(2)The PCWM indoor ice melting test was designed.The ice melting performance of PCWM in the cooling stage and the heating stage at-5℃、-10℃and-15℃ were analyzed.The results show that with the increase of DTC content,the ice melting rate of PCWM increases gradually in the cooling stage,and decreases gradually in the heating stage.At the same time,the ambient temperature has a great impact on the ice melting ability of PCWM.The temperature decreases,and the ice melting ability of PCWM decreases gradually.(3)PCWM indoor snow melting test and outdoor snow melting test were designed.In the indoor snow melting test,the snowfall intensity,snow compaction and test environment temperature were designed by the self-made mold;The snow melting performance of PCWM under different snow cover areas were analyzed in outdoor snow melting experiments.The results show that the snow-melting ability of PCWM decreases with the increase of snowfall intensity and snow density,and the greater the snow coverage area of PCWM in outdoor environment,the lower the snow-melting ability.(4)The direct pull-out test of ice-road adhesion was designed.The supplementary scheme for the energy of the test piece before the test was designed,and the adhesive force between the ice layer and the PCWM test piece at different test temperatures was measured by using the freeze-break test instrument.The results show that PCWM can reduce the adhesion between ice layer and pavement effectively,but the decrease of temperature and the extension of low temperature duration will increase the adhesion.(5)Outdoor temperature regulation performance test was designed.The outdoor cube model and temperature sensor layout scheme were designed by ourselves.Through recording the temperature change of the model in the cooling stage in the outdoor environment,the temperature field distribution and the change of the characteristic interface in the model are studied,and phase change temperature regulation value(PCTRV)is proposed as DTC phase change temperature regulation index.The capability and mechanism of DTC phase-change temperature regulation are characterized effectively,and the impact of direct sunlight on the effect of DTC phase change temperature regulation has been pointed out. |
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