Research On The Preparation And Performance Of Specialized Asphalt For Pervious Pavement

With the rapid development of transportation in China,the function of asphalt pavement has been paid more and more attention.The drainage function of asphalt pavement has been widely concerned,but its special open gradation structure requires that the asphalt should have high cohesion,anti-spalling and antirutting characteristics.In this paper,rubber asphalt was used to prepare rubber asphalt-based permeable pavement asphalt with different content of SBS and its performance was studied.The swelling and degradation of rubber asphalt are studied according to the change trend of 135°C viscosity and viscoelasticity.The influence of rubber asphalt viscoelastic system and particle size on its rheological properties are studied by using dynamic mechanical analysis(DMA).The influence of SBS content on the performance of special asphalt is investigated.Finally,ten specialized asphalt binders are selected and used in permeable asphalt mixture tests.The results show that:The swelling and degradation of rubber asphalt show that the swelling state of rubber asphalt is full swelling when the viscosity of rubber asphalt increases to a stable state at constant temperature swelling stage.When the reaction temperature rises,the viscosity of rubber asphalt continues to increase because of swelling,and then decreases with the deepening of degradation degree.When the degradation time is long enough,the viscosity reaches a stable value.The time for small rubber asphalt to reach full swelling and degradation is shortened,and the swelling and degradation reactions are more likely to occur.The swelling degree of rubber asphalt is helpful to improve its resistance to permanent deformation and rutting,while the degradation process weakens its elasticity and deformation recovery ability.The effects of swelling/degradation degree on the performance of rubber asphalt show that with the increase of degradation degree,the high temperature performance of rubber asphalt decreases significantly,the zero shear viscosity decreases gradually,and the recovery rate R% increases first and then decreases,while the non-recoverable compliance Jnr increases continuously.Total swelling asphalt has the best rutting resistance at high temperature,while total degradation asphalt is the worst.In terms of low temperature performance,full-swelling asphalt is the worst,while full-degradation asphalt is the best.The particle size of rubber powder has great influence on the high temperature performance of the whole swelling and partial degraded rubber asphalt,but has little effect on the whole degraded rubber asphalt.The shear thinning of fully swollen asphalt is obvious and tends to be non-Newtonian fluid,while the Newtonian fluid range of full-degradation asphalt is wider.The influence of SBS content on the performance of special asphalt shows that SBS can improve the high temperature rutting resistance,resilience and low temperature performance of special asphalt.Within the scope of study,the high and low temperature performance of full-swelling asphalt can not meet the requirements of permeable asphalt pavement for asphalt binder performance at the same time,while partial and full-degrading asphalt can meet the performance requirements when the content of SBS reaches 3wt%.The application study of special asphalt mixture for pervious pavement shows that the final gradation of pervious asphalt mixture is 16.3% when the target void ratio is 20%,and the optimum asphalt-aggregate ratio is 4.23%.The asphalt mixture prepared from 10 kinds of special asphalt can meet the performance requirements of permeable pavement at high temperature,voidage,leakage and dispersion,strength,water stability and water permeability.The feasibility of using different viscoelastic rubber asphalt binders for permeable asphalt pavement is verified.