Mechanical Response Analysis And Performance Evaluation Of Adhesive Layer Materials Of Polymer Concrete Deck Pavement Of Beijing Wuzicun Bridge

Wuzicun bridge in Fangshan,Beijing is a long-span simply supported steel box girder bridge.A new type of polymer concrete deck pavement material is proposed for its pavement.Waterproof adhesive layer is the key to form an organic whole of steel bridge deck pavement structure,and its material selection is closely related to the type of pavement.As a new type of steel bridge deck pavement material,polymer concrete has better performance than traditional asphalt based materials.However,if the waterproof bonding layer is not properly selected,the bridge deck is easy to be damaged and the service life of pavement is seriously affected.Based on this,combined with the structural characteristics of the bridge,traffic and climate conditions,this paper analyzes the interlayer mechanical response,puts forward the interlayer strength control index,evaluates the interlayer mechanical properties of typical bonding materials through laboratory tests,and recommends the appropriate bonding materials.Firstly,the three-dimensional finite element model of wuzicun bridge in Fangshan District of Beijing is established by using ABAQUS software.Further analysis shows that the most unfavorable load position of interlayer stress of the whole bridge occurs in the web area,and the normal temperature(25oC)The maximum tensile stress and shear stress are 0.97MPa and0.91MPa respectively;According to the calculation method in technical code for design and construction of highway steel bridge deck pavement(JTG/T3364-02—2019),and according to the highway grade coefficient and traffic load grade correction coefficient of the line to which the bridge belongs,the pull-out strength index and shear strength index of the lower layer of the target bridge at room temperature are determined to be 1.87 MPa and 1.73 MPa respectively;The influence of interlaminar contact condition,horizontal force coefficient,temperature and pavement thickness on interlaminar stress is analyzed by orthogonal test.The order of significance of each factor on shear stress is interlaminar contact condition>horizontal force coefficient>thickness>temperature,and the order of significance on tensile stress is pavement thickness>interlaminar contact condition>temperature>horizontal force coefficient.Then,the optimum binder aggregate ratio of PC-13 polymer concrete is 7.0%by Marshall test;The surface dry time of three kinds of adhesive materials(GW-SL911M one component polymer,0807 polyurethane adhesive and epoxy resin)at different temperatures were measured.0807 polyurethane adhesive had too long surface dry time,which did not meet the interlayer technical requirements and was no longer used as an alternative adhesive material;Through 45°The interlaminar structure strength was systematically studied by shear test and pull-out test.The influence of interlaminar treatment measures such as aggregate spreading and antirust paint coating on interlaminar strength was analyzed.The optimum coating amount of GW-SL911M single component polymer adhesive layer and epoxy resin was 0.64kg/m~2 and 0.62kg/m~2respectively.Finally,the effects of temperature change and different aging conditions such as freeze-thaw cycle,temperature aging and ultraviolet light on the interlaminar strength of the two adhesive layers were studied.The interlaminar shear strength and drawing strength decreased significantly with the increase of temperature,but the polymer adhesive layer had lower temperature sensitivity than epoxy resin;The temperature aging resistance and freeze-thaw resistance of the polymer adhesive layer are better than those of the epoxy adhesive layer.The UV light can not act on the waterproof adhesive layer through the pavement layer,so it has little effect on the interlaminar strength;The effects of stress level and freeze-thaw cycles on the fatigue properties of two kinds of adhesive layer materials were studied by shear fatigue test.With the increase of shear stress and freeze-thaw cycles,the fatigue life of adhesive layer decreased correspondingly,but the fatigue life of polymer adhesive layer was always higher than that of epoxy resin adhesive layer.Therefore,the order of waterproof adhesive layer materials recommended in this paper is GW-SL911M single component polymer and epoxy resin.