The Research On Interface Damage Around Rubber Particles Of Porous Elastic Mixture

Porous elastic road surface(PERS)is a kind of noise reduction pavement structure which uses rubber particles as damping materials,polyurethane as binder and large voids.As the design key of the porous elastic mixture,the high content of rubber particles will lead to a sharp reduction in durability,and may lead to the road rebound deformation is too large,the vehicle driving energy consumption increases,so this paper uses the low content of rubber particles in the design of the porous elastic mixture.According to the design of the mixture proportion,the road performance,the evolution of the rubber particles’ interface damage and the internal void of the porous elastic mixture based on test and PFC,this paper lay a certain foundation for improving the durability of the porous elastic mixture.Firstly,the single component polyether polyurethane was selected as the binder of the porous elastic mixture;the mix proportion of the porous elastic mixture is designed according to the grading of open grading OGFC-13;the polyurethane content and void ratio of the porous elastic mixture with the volume fraction of rubber particles(10%,20% and 25%)are determined.Secondly,the road performance test was carried out with the selected combination of porous elastic mixture with low rubber particle content.The results showed that: when the polyurethane content is higher and the rubber particle content is less,the splitting strength and dynamic stability is larger,but the loss of standard dispersion and three kinds of immersion dispersion is smaller.the high temperature and water environment had a greater impact on the water stability of porous elastic mixture.The results of low temperature bending test showed that with the increase of the content of rubber particles,the flexural tensile strength and flexural stiffness modulus will decrease,and the failure strain will increase,the failure strain can’t be used as an index to evaluate the bending performance of porous elastic mixture.Then,based on the cyclic loading test and CT scan,the internal interface damage of porous elastic mixture was studied.There are four stages of interface damage(deformation)around rubber particles in porous elastic mixture: damage weakening(initial stage of deformation),damage initiation(early stage of deformation),damage stable development(middle stage of deformation)and damage rapid development(late stage of deformation).The failure of the test piece is mainly concentrated in the height range of 10-40 mm,and the failure type is the expansion failure of the bottom layer.The internal reason is that the interface damage around the rubber particles develops faster in the range of 10-40 mm,when the interface damage within the range reaches the maximum value,the interface around the top and the bottom of the test piece also has the bearing capacity.According to the polynomial fitting,the internal porous elastic mixture is obtained The damage evolution equation of structure and interface around rubber particles.Finally,the cyclic loading test of the porous elastic mixture was simulated by using the PFC software.It is found that the PFC simulation can be used as a reliable research method for the damage of the porous elastic mixture.The contact tension of the rubber particlepolyurethane interface,the aggregate-polyurethane interface and the polyurethane interface in the specimen is negative exponential distribution,and the weakest structural link in the porous elastic mixture is the rubber particle.There are four stages of crack development in the porous elastic mixture: initial stage,micro crack accumulation stage,stable crack growth stage and unstable crack growth stage.These four stages correspond to the damage development in the rubber particle-polyurethane interface and are consistent with the results of the real test.The research results of this paper reveal the structural weakness of the porous elastic mixture,put forward the damage evolution law of the rubber particle interface,and explore the relationship between the macro performance and micro damage of the porous elastic mixture,which is of great significance to the study of the durability of the porous elastic mixture.