| Some highway bridges built in recent years have experienced traffic congestion and vehicle backlog traffic problems after they are in service.New bridges require a lot of investment,cost a lot and waste resources on existing old bridges.Therefore,many cities adopt the method of widening bridges to improve traffic capacity and alleviate the growing traffic demand.In the widening project of the old bridge,the reinforced concrete cantilever beams of the original bridge deck need to be reinforced.Due to factors such as the control of the bridge deck elevation and the reduction of the thickness of the bridge deck pavement to reduce the constant weight of the bridge,it is often encountered that the asphalt pavement and the cantilever reinforced steel protection layer are generally insufficient.In engineering practice,it was found that after a period of operation of the bridge widening project,due to the insufficient thickness of the reinforcing steel protective layer,it was deformed,and the asphalt layer of the bridge deck widening section was prone to pits and other diseases,which was extremely unfavorable to the bridge structure durability and driving safety.Overlaying the anti-slip wear layer can protect the bridge and satisfy the safety and comfort of the vehicle,which is of great significance for ensuring the safety of the vehicle.In this paper,the material composition and structure optimization of the epoxy asphalt ultra-thin anti-slip wear layer of the old bridge widened by relying on the bridge deck pavement restoration engineering system of the widened section of the old bridge of Tianfu Interchange is proposed.technology,optimizing the material composition and interlayer treatment of the ultra-thin anti-slip layer of epoxy asphalt in the old bridge,to extend the service life of the wear layer and improve the anti-slip durability.The main research results are as follows:(1)The technical properties of the anti sliding wearing course of epoxy asphalt are studied through laboratory tests.The ratio of epoxy asphalt binder is optimized by using orthogonal test,considering the effects of ductility,anti-aging and curing time of epoxy asphalt binder.(2)Through the pull-out test,the factors affecting the bonding performance between epoxy asphalt ultra-thin wearing layers are studied,and the influence law between the interface treatment method of bridge deck concrete leveling layer and the bonding strength is analyzed.The test results show that the bonding effect after groove treatment is significantly better than that of surface roughening,and the bonding effect increases with the increase of groove depth,and has a negative correlation with the groove spacing;epoxy asphalt binder and aggregate The adhesion performance between the particles was positively correlated with the abrasion temperature,loading time and aggregate particle size.(3)The interlaminar torsional shear performance of different wear layer structures was detected by interlaminar torsional shear,the optimal amount of cement was recommended,and the appropriate anti-slip wear layer structure combination and construction process were optimized.The test results show that when the amount of epoxy cementitious material at the bottom of the structure is too high,the phenomenon of the whole piece falling off easily occurs;although the single-layer aggregate structure has high torsional shear strength,its overall structural toughness is poor,prone to brittle failure and adaptable to deformation.poor.(4)The durability performance of epoxy anti-slip wear layer was systematically studied by accelerated loading wear test equipment.The test results showed that BPN and MTD of epoxy asphalt ultra-thin wear layer decreased rapidly in the early stage,then slowed down,and finally tended to decrease.For stability,the ultra-thin anti-slip wear layer has excellent anti-slip and anti-peeling durability. |
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