Research On Failure Mechanism Of Mechanical Properties Of Rigid Flexible Interface Of Composite Pavement

The composite pavement formed by cement concrete layer and asphalt mixture has been widely used in China,which not only improves the bearing capacity of the road,prolongs the service life of the road,but also improves the service level of the road.At present,the design specification and construction specification of composite pavement are not mature,and there are still problems of fracture,pit and groove in the actual road use.In order to find the source of these problems,many road scholars start from the directions of bond layer,reflection crack,bottom stress and deflection value of composite pavement,and study the direction of mechanical properties of rigid flexible interface of composite pavement It is also of great significance and practical value.In this paper,through the indoor test,the influence of the actual road construction,environmental factors,as well as the change of the mechanical properties of the Composite Pavement interface under the influence of the pavement structure itself are studied and analyzed.In this paper,cement concrete layer + binder layer + asphalt overlay is used as the typical structure of composite pavement.The mixture ratio of rigid cement concrete layer and flexible asphalt overlay is designed respectively,and the main materials for binder layer are determined,so as to complete the typical structure design of composite pavement required by the test.In this paper,45 ° oblique shear test,three-point bending test and flexural test are used to study the interface shear strength,flexural tensile strength and flexural strength of composite pavement under different influence factors.The factors such as different asphalt content of bond layer,segregation and aging of asphalt overlay,rolling strength,rolling times,thickness of asphalt overlay and water are studied respectively The failure mechanism of interface mechanical properties caused by different factors is analyzed.Through three kinds of different mechanical properties tests in the laboratory,the different influencing factors related to the mechanical properties of the interface are studied and analyzed,and the influence of different asphalt content and water action of the bonding layer on the mechanical properties of the interface is obtained,and the influence of the bonding layer on the mechanical properties of the interface is also analyzed;the asphalt overlay has different degree of segregation and aging and the effect of water on the interface is obtained The influence of asphalt overlay on interface mechanical properties is analyzed.The influence of composite factors in pavement construction on interface mechanical properties is obtained.The influence of single factor on rolling strength,rolling times and thickness of asphalt overlay is studied.The results show that all three factors have certain influence on interface mechanical properties,and then on three factors Through the orthogonal test,the influence degree of three factors on the interface mechanical properties is obtained,which are all significant factors,and the influence of pavement construction conditions on the interface mechanical properties failure is analyzed.In this paper,the failure mechanism of interface mechanical properties of composite pavement is studied and analyzed.The function of the bond layer affects the bond effect between the cement concrete and the asphalt overlay of the composite pavement.The segregation and aging of the asphalt overlay change its own strength characteristics and road performance.The design of pavement construction conditions also affects the strength characteristics and road performance of the asphalt overlay,and under the action of water,the composite pavement is prone to water damage or even reduce the bond effect of the bond layer Use.To sum up,when all the influencing factors make the interface mechanical properties reach the worst,the composite pavement will have the phenomena of bond layer sliding,cement concrete cracking,asphalt overlay cracking and so on under the repeated action of vehicle load,until the composite pavement has the pavement diseases such as sliding damage,slab bottom hollowing,pit and groove,which makes the interface mechanical properties of the composite pavement completely invalid The service performance and service level of the composite pavement are reduced,and the service life of the composite pavement is reduced.This paper mainly analyzes the influence factors that are easy to occur in road construction,studies the influence of road environment and its own factors,studies the influence rules of different influence factors on the interface mechanical properties of composite pavement,analyzes the influence of different influence factors on the interface mechanical properties,obtains the failure mechanism of rigid flexible interface mechanical properties of composite pavement,and summarizes the results In the actual road construction,we should pay attention to avoid the problems.The research results of this paper have important guiding significance for the design and construction of composite pavement.