Experimental Study On Cooling Techniques Of Low-heat Absorption Asphalt Pavement

As a common pavement type,the asphalt pavement takes in heat easily in summer,which makes the pavement materials worse under the load of vehicle and affects the surrounding thermal environment,resulting in damages of pavement such as rutting and the aggravation of the urban heat-island effect.Therefore,an effective cooling mode that is suitable for asphalt pavement will be of great significance.The research mainly focuses on the two cooling methods including the thermal-resistant materials and the heat-reflective coating.A variety of cooling ways,which include the heat-reflective coating,thermal-resistant adhesive layer,thermal-resistant asphalt,thermal-resistant aggregate and combinations of these cooling ways are researched through a series of experiments including the indoor radiation simulation test,the thermal physical property test and the road performance test.On the basis of the analysis of the the relevant test equipment’s deficiency in the current researches of the low-heat absorption pavement,a new device for measuring the thermal property of pavement materials is designed,which can measure the cooling effect,the thermal diffusivity,the heat conductivity coefficient and the solar reflectance ratio.The cooling effect of the heat-reflective coating R1 and two kinds of thermal-resistant materials including expanded perlite powder and ceramic sand of adhesive layer are studied by the indoor irradiation simulation test.Likewise,the cooling effect of thermal-resistant ceramsite aggregate and three kinds of thermal-resistant asphalt including expanded perlite asphalt,rubber asphalt and ceramic asphalt are studied in the same way.The cooling mechanism and the influence on road performance of the four cooling ways are researched by the thermal physical property test and relevant pavement performance tests respectively.The results show that the four kinds of cooling ways perform differently in cooling effect,the heat-reflective coating can significantly reduce the surface temperature and the bottom temperature of the specimen at the same time.And,three kinds of use of thermal-resistant materials can effectively reduce the accumulation of heat in the road.In addition,the expaned perlite asphalt not only can reduce the heat in the road but also can improve the high-temperature stability of asphalt mixture.Finally,the four cooling ways are used in conjunction for four combinations.On the base of coMParision of the cooling effect,road performance and economy,the optimal composite low-heat absorption functional layer that performs well in these aspects is elected,the upper surface temperature of the specimen applying this kind of composite functional layer is reduced by six point four degrees Celsius,the bottom temperature is reduced by eight point one degrees Celsius.The paper improves the test device of low-heat absorption asphalt pavement and explores the study on cooling ways of asphalt pavement.The results of this paper provide certain reference and guidance for the study of low-heat absorption pavement.It is greatly significant for the advancement of the study on low-heat absorption pavement and the improvement of the working condition of asphalt pavement.