Study On The Application Of Permeable Asphalt Pavement Based On The Sponge City

In recent years,as urban flood disaster happens more and more frequently,the concept of the sponge city was arisen at the right moment.Permeable asphalt pavement plays an important role in sponge city,while the research and applications of permeable asphalt pavement based on sponge city in China are still not well developed.Therefore,based on the project piloted for sponge city in Kunshan,this paper studied on the application of permeable asphalt pavement based on sponge city.In this paper,the research on the component of asphalt binder for permeable asphalt pavements is firstly conducted.The optimal combination of raw materials is selected by performing various properties tests of the asphalt binder.Then the mixture design was conducted and laboratory experiments were performed to ensure the mixture performances are qualified.Subsequently,the weeping property of pavement with different structures was analyzed by finite element method,and the combination of pavement structures which matched the rainfall intensity was recommended.Finally,the water circulation system based on the permeable asphalt pavement was designed,and the experimental road was constructed and proved to be qualified.For the raw materials used in the permeable asphalt pavement,this study conducted a comprehensive comparison regarding the effects of different types and contents of high viscosity additives on the performance of asphalt binder.The results showed that the use of SBS modified asphalt to produce high-viscosity asphalt binder could significantly improve the 60°C dynamic viscosity and high temperature performance of high-viscosity asphalt binder and reduce the impact on low-temperature performance compared to 70#base asphalt.The 60°C dynamic viscosity of the high-viscosity asphalt binder made of SBS modified asphalt has a high correlation with the softening point with R~2 of 0.83.The correlation between the penetration and the m value,penetration and creep stiffness are also strong,whose R~2 are 0.97 and 0.79,respectively.When the amount of high viscosity additive is in the range of 0~12%,the dynamic viscosity of high-viscosity asphalt binder will show three different growth stages as the additive content changes.With the increase of additive content,the dynamic viscosity of high-viscosity asphalt binder will gradually increase.The growth rate increased firstly,then remained unchanged,and finally decreased.For the mixture used in the permeable asphalt pavement,this study conducted the mixture design according to domestic and foreign specifications.It was also found that the addition of anti-cracking agent in this study can greatly reduce the leakage and scattering loss of the mixtures.For the geometry structure of permeable asphalt pavement,this study used Geo-studio series software to analyze the weeping property of pavement with different structures.It was recommended that 2.5%transverse slope+4cm permeable layer could guarantee that there is no water film in the road surface under the intensity of heavy rain;at the same time,it was recommended to use 2%or 2.5%transverse slope+4cm upper permeable layer+6cm base permeable layer as double-layer permeable asphalt pavement,which could ensure no water film on the road surface under violent rain conditions.For the design of the water circulation system in the sponge city,this study regarded the double-layer permeable asphalt pavement as the principle part,and the sinking green space as the auxiliary facility.Then the water circulation system was established with the addition the modified road basement,curb structure and the drip irrigation system.Finally,a testing road of160 m long and 3.5 m wide was paved on Chaoyang Road in Kunshan and passed the quality acceptance.