Research On Interface Contact Performance Of Asphalt Concrete Bridge Deck Pavement Repair Block

Asphalt concrete pavement has a variety of diseases due to the combined effects of environmental factors and vehicle loads during daily use.Among them,pit-type diseases occur more frequently,and the probability of damage in a short period of time after repair is greater.At present,the pothole repair block is limited by many factors such as its own material composition,construction technology and external environment,and many kinds of damage often occur soon after the repair.In this paper,through a field survey of the use of pothole repair blocks for municipal roads and bridges in Chongqing,the types and numbers of repair block damage are counted,and the main types of damage for pothole repair blocks in Chongqing area are obtained.The ABAQUS finite element simulation software is used.The force law of the interface between the repair block and the old pavement under the moving load is analyzed,and the factors that affect the bonding performance of the new and old pavement interface are studied through experiments to provide a theoretical basis for the maintenance and repair of the bridge deck pavement.The following research results:(1)According to the bridge structure,4 active continuous rigid frame bridges and 3municipal roads were selected for on-site investigation.The investigation found that there are five main types of secondary damage in the repair of the asphalt pavement and bridge deck paving potholes in this area: loose spalling,crowding,sinking rutting,interface failure and cracking,of which interface failure is the main form.(2)The ABAQUS finite element software was used to establish the overall model of the upper structure of a single box girder and the pavement repair block of the bridge deck.The force law of the interface between the repair block and the old pavement layer under the action of rectangular uniformly distributed moving load was analyzed,and the effects of different loads were studied.The influence of position on the interface force,the most unfavorable load position is found when the load center line of a single wheel acts on the center line of the repair block.(3)Under the most unfavorable load conditions,the force law of the horizontal and vertical interfaces along the depth and along the edge of the interface was obtained,the possible failure points of the horizontal and vertical interfaces were found,and the possible locations and locations of interface failures were clarified.Reason: The overload rate is used to indicate the overload state of heavy load,and it is found that when the overload rate reaches 200%,the maximum tensile stress and maximum shear stress τyz of the transverse interface are increased by 104% and 103% respectively compared with the standard axle load.(4)When the edge interface of the repair block is inclined at a certain angle,the mechanical response at the interface is greatly improved compared with the vertical interface.The larger the interface inclination,the larger the contact area between the new and the old interface,the stronger the bonding performance,and the maximum tensile stress on the interface And the maximum shear stress is significantly reduced.When the slotting angle exceeds 45°,the maximum tensile stress and the maximum shear stress on the interface begin to increase.At the same time,considering many restrictions such as material saving and actual construction conditions,it is recommended that the transverse interface be slotted at 30°～45° when conditions permit.To improve the bonding performance between the new and the old interface.(5)Using the oblique shear test as an evaluation method,changing factors such as temperature,humidity,adhesive types and interface treatment methods,analyzed the shear strength of different bonding layer combinations under different conditions,and found that as the temperature rises and the water immersion time increases,The interfacial bonding performance is decreased;the bonding performance of cold liquid-filled asphalt is slightly higher than that of PC-3 emulsified asphalt;AC-5 asphalt sand as a leveling layer can effectively improve the interfacial bonding performance,and at the same time has certain resistance to temperature changes and moisture intrusion Ability,in practice,an additional layer can be added to increase the service life of the repair block.