Development And Application Of A New Waterproof Adhesive Layer Material For Heavy Traffic Concrete Bridge Deck

Asphalt concrete paving layer of cement concrete bridge deck under heavy traffic produces early elapse,convection and other diseases,it is greater related to the destruction of waterproof adhesive layer.The service life of the bridge deck pavement determined by the selection and material design of the waterproof adhesive layer directly,even the durability and safety of the bridge structure is affected.Therefore,the stress characteristics,material properties of the waterproof adhesive layer and the pavement system performance need be depth studied.First,The abaqus software is used to establish a simple-supported beam bridge model of cement concrete.The shear stress of the waterproof adhesive layer under different loading positions and different asphalt concrete pavement thickness is calculated to determine the most unfavorable load position and the appropriate thickness of asphalt concrete pavement.The development principle of the waterproof adhesive layer material of the heavy traffic cement concrete bridge deck is the shear strength not less than 0.75 MPa by calculating the shear stress of the waterproof adhesive layer under the temperature-load coupling effect.Secondly,the traditional cement-based infiltrated crystalline materials is modified and developed a new type of cement-based waterproof adhesive layer material.It is found that its heat resistance,water impermeability and anti-pollution properties are good,and the low temperature performance meets the specification requirements.At the same time,the three factors and four levels of orthogonal test is used to determine the optimum construction process of the cement-based waterproof adhesive layer material as follows:the cement concrete slab should be napped,the optimum amount of cement-based waterproof adhesive layer material is 5.0 kg/m~2,and the best setting time is 0.5h.Thirdly,The three commonly-used asphalt-bases waterproof adhesive layer of SBS modified asphalt,rubber asphalt and waterborne epoxy resin modified asphalt are selected to compare with the cement base waterproof adhesive layer.The shear and pull performances of four types of waterproof adhesive layer under different temperatures,before and after water immersion,before and after freeze-thaw and before and after long-term aging are evaluated.It is found that the shear strength of the cement-based waterproof adhesive layer is 1.62MPa(greater than 0.75 MPa)at 60°C,which meets the development principle of the waterproof adhesive layer material of the heavy traffic cement concrete bridge deck,and the shear strength of the three commonly-used asphalt-based waterproof adhesive layer are 0.19?0.19 and 0.41MPa,they are all less than 0.75 MPa.The cement-based waterproof adhesive layer has superior shear strength and pull strength,and the high temperature performance,water stability and freeze-thaw resistance performance of the cement-based waterproof adhesive layer is superior than the asphalt-based waterproof adhesive layer.The water-impregnated rutting test was used to evaluate the anti-deformation performance of the four waterproofing adhesive layer.It is found that the high temperature performance and deformation resistance of the cement-based waterproof adhesive layer are significantly better than those of the asphalt-bases waterproof adhesive layer.Due to the inapplicability of the freeze-thaw cycle test method of bituminous mixture to the cement-based waterproof adhesive layer,this paper presents a test method for evaluating the freeze-thaw resistance of cement-based waterproof adhesive layer by freeze-thaw cycles at-18°C±2°C for 4 hours,5°C±0.5°C for 1 hour,and freeze-thaw cycle 10 times.Finally,the asphalt pavement performance climate zoning method is used,and combined with mechanical calculations and indoor shear test results,the applied areas of four waterproof adhesive layer are determined.The cement-based waterproof adhesive layer is suitable for the hot summer and cold winter areas,the SBS modified asphalt waterproof adhesive layer is suitable for the cool summer and cold winter areas,the rubber asphalt waterproof adhesive layer is suitable for the cool summer and cold winter wet areas,the epoxy resin modified emulsified asphalt waterproof adhesive layer suitable for summer cool winter cold humid area.It provide a theoretical basis for the selection and application of waterproof adhesive layer.