Research On The Effect Of Continuous Construction Method On Base And Interlayer Contact State In Asphalt Pavement

The early disease of the semi-rigid base asphalt pavement seriously affects its service life.The horizontal force generated by the braking state of the vehicle causes shear failure and cracking of the asphalt pavement,which is the main cause of early damage.The quality of interlayer contact and the prevention and treatment of crack problems have become technical problems in the application of asphalt pavement,asphalt pavement foundation-surface continuous construction method was proposed.Through the flexible paving,the interlayer contact state between the base and the surface layer is improved,the overall structural strength of the asphalt pavement is improved,and the bond strength between the base and the surface layer is enhanced to improve the shear resistance of the pavement structure.Asphalt pavement base-surface continuous construction method can fundamentally prevent the crack problem of semi-rigid base asphalt pavement,and provide a high-temperature,stable water content curing environment for the semi-rigid base layer,and improve the semi-rigid base layer resistance to dry shrinkage and temperature shrinkage cracking.Therefore,the generation and development of reflective cracks will be controlled.In order to research the effect of CCM on base and interlayer contact state in asphalt pavement,firstly the temperature field of pavement structure under CCM was simulated by ABAQUS,the effects of CCM curing temperature on the performance of cement stabilized macadam base was studied through the paving of laboratory tests,the influence of CCM on the curing temperature,early strength and moisture content of the base course were verified by the test road.The results show that CCM can help to increase the average temperature of the base layer,the variation of the water content of the test road base layer is small,the temperature shrinkage dry and wet cracks of the semi-rigid base layer are reduced,and the excessive reflection cracks are prevented,thereby helping to delay and reduce the occurrence of early damage on the asphalt pavement.The effect of CCM on the friction coefficient and embedding depth between the base layers was studied through the paving of laboratory tests,and the theory analysis was made through compaction work of surface layer and high temperature characteristic of CCM.The bond performance between the base-surface layer of the continuous and conventional construction test pieces and the bond performance between the base layers of different embedding depths were compared by the multi-angle oblique interlaminar shear and pull-out tester.According to Mohr-Coulomb strength theory draws multi-angle interlaminar shear strength map,introduces the concept of shear energy W_p and W_c to study the ability of asphalt pavement base layer to resist shear deformation.The shear strength line and the shear energy W_p and W_c are studied to evaluate the contact state between the base and the surface of the asphalt pavement.The analytical results show that even under the high temperature condition of 60°C,the base-face layer of the test piece formed by the continuous construction method still has good bond strength.It shows that the cohesive force c provided by the asphalt material is continuously lost with the increase of temperature,and continuous construction can provide greater internal friction resistance for the base layer.When shear tests were carried out on specimens formed by continuous construction at 25°C and 60°C test temperatures,the shear energy W_p and W_c required for the base-to-surface interlayer failure were much larger than those of conventional construction test specimens.The CCM can improve the interlayer contact state,enhance the bonding strength between base and surface layer and improve the shear resistance of pavement structure.Relying on Jiangzhao and Guangqing highway to design and construct continuous construction test roads,we will continuously improve and improve some key technical problems in continuous construction methods.Through years of tracking and testing,the road conditions of continuous construction and conventional construction molding test roads were analyzed,and the positive effects of continuous construction on preventing cracks and improving the contact state between the base layers are verified.