Research On Optimization Of Anti-clogging Performance Of Permeable Asphalt Pavement

With the development of the sponge city,the permeable asphalt mixture has become one of the "sponge city" materials.The characteristics of good seepage,pressure resistance,wear resistance,anti-skid,environmental protection,beauty,comfort,sound absorption and noise reduction are showed in the substantive application of the permeable asphalt pavement,which has become a "breathing" urban landscape pavement.However,the permeable asphalt pavement is easily clogged in the process of use,and as the congestion increases,the water permeable function decreases continuously until it is completely lost,therefore,it is necessary to improve the anti-clogging performance of permeable asphalt pavement.The anti-clogging performance and road performance of permeable asphalt pavement are mutually restricted.It is important to maximize the balance between anti-clogging performance and pavement performance to improve the quality of permeable pavement.In this paper,the permeable asphalt mixture was taken as the research object,and the four influencing factors of porosity,maximum nominal particle size,gradation type,and asphalt type were used as test factors to design a balanced optimization test for road performance and anti-clogging performance of permeable asphalt mixture Based on the quantification and analysis of sensitive factors,the influence law of each test factor on road performance and anti-clogging performance was studied,and the PAC grading optimization was carried out based on the research results combined with the grey correlation comprehensive analysis method.Firstly,the permeable asphalt concrete specimen with different structural parameters were designed and prepared to study the influence of different test factors on the road performance of permeable asphalt mixture.Secondly,a mathematical model for estimating the number of clogging times was established to evaluate the anti-clogging performance of permeable asphalt mixture,and the self-made anti-clogging performance evaluation system was used to simulate the PAC rainfall clogging process through laboratory tests.Finally,on the basis of optimizing the anti-clogging performance and combining the road performance,the gray correlation analysis method was used to optimize the PAC gradation.The results show that the higher the porosity of the permeable asphalt mixture,the coarser the gradation,the larger the maximum nominal particle size,the stronger the water permeability and anti-clogging performance,but the poor water stability and anti-scattering performance;the coarser the grade Mixing with a larger maximum nominal particle size can improve the high-temperature stability of the permeable asphalt mixture.The increase in porosity causes the high-temperature stability to rise first and then decrease.When the porosity of the permeable asphalt mixture reaches about 21%,its high temperature stability is the strongest;the use of high viscosity modified asphalt as a binder can significantly improve the PAC's high temperature stability,water stability and anti-scattering performance,but has no significant effect on water permeability and anti-clogging performance.Based on the research on road performance and anti-clogging performance,PAC grading is preferred.The largest nominal particle size is 13 mm,the target void ratio is 21%,and the grading type is a coarser gradation.The range is 9.5 to 16.0mm and 4.75.The ratio of the aggregate content of ? 9.5mm particle size is variable.The gray correlation analysis method is used to optimize the PAC grading.When the ratio of the aggregate content of 9.5 to 16.0mm and 4.75 to 9.5mm particle size is 1.2,the PAC13 gradation is optimal.The PAC grade finally optimized in this study has high anti-clogging performance and can also ensure good road performance.