Research On Repairing Interface Performance Of Wear Layer On Ultra-High Performance Composite Deck

The ultra-high performance new composite deck pavement system(steel deck-UHPC-wear layer)solves two technical problems of fatigue cracking and poor durability of steel bridge deck pavement.UHPC has an extremely high durability and a service life of up to 100 years,while the asphalt wear layer has a service life of 8-12years.During the service of the bridge,the wear layer must require multiple milling and resurfacing.Therefore,it is necessary to study not only the performance of the first paving wear layer and the new UHPC interface,but also the deterioration of the interface between the milled resurfacing wear layer and the old UHPC.In this paper,the UHPC-asphalt wear layer interface conditions before and after repair are analyzed and compared,and the following work is completed:(1)Based on the shear failure energy analysis principle,the shear fracture energy evaluation is proposed.Through the shearing and drawing tests,the UHPC-mechanical properties and aging resistance are analyzed by the immersion damage,high temperature damp heat and chloride salt erosion.The test results show that the UHPC-asphalt wear layer has excellent mechanical properties,but the high temperature sensitivity is high.The load-interface displacement whole process curve shows four stages,and the fold line can be used to simplify the model.Under three unfavorable natural environments,the composite test piece The deterioration resistance of interlayer shear performance is similar,but the degree of aging is different.The environmental impact order is:water damage>chloride salt corrosion>high temperature and high humidity;shear fracture energy comprehensively reflects the interlaminar shear strength and the amount of shearing displacement.The shear strength of the interlayer is more fully characterized;the shear strength has the same tendency as the tensile strength of the adhesion.A linear function can be used for fitting between the two.The influence of environmental factors on the tensile strength of the interface is greater than the shear strength.(2)Simulating the repair process of asphalt wear layer on the original test block,analyzing the influence of the binder dosage on the repair effect and the aging resistance of the repair interface through laboratory tests.The test results show that the amount of binder in the repair process has a significant effect on the repairing effect.It is recommended to use 0.7kg/m~2 of binder.When the dosage is 0.5kg/m~2,0.3kg/m~2,the repair interface performance will be different.The adverse environmental factors have a significant impact on the repair interface performance.The shear strength,shear fracture energy and adhesion pull strength of the repair interface decrease with the increase of the number of cycles.(3)By comparing the difference in mechanical properties and durability between the new pavement and the resurfacing specimen,the repair effect of the asphalt wear layer was comprehensively evaluated.The comparative analysis shows that the0.7kg/m~2 binder is used in the resurfacing of the wear layer,and the mechanical properties of the repair interface are basically the same as the new pavement interface.Under the adverse environmental conditions,the shear strength of the interface between the new paving and the resurfacing specimen is The shearing fracture energy and the tensile strength of the adhesion are basically the same,but under the same cycle,they are smaller than the new one,and the difference between the two increases with the number of cycles,indicating that the interlayer is resistant to aging after repair.Performance has declined to some extent.At the same time,the construction process of the new paving and resurfacing wear layer of the new composite deck pavement system and the main points of the construction are briefly proposed,which will provide reference for the subsequent practical engineering application.