Bridge Deck Pavement Material And Structure Design Based On Rubber Asphalt

Based on the Jiangyin Yangtze River Bridge,to solve the problem that deck pavement is easy to produce cracks and ruts,this paper provides the deck pavement structure of rubber asphalt SMA-13 upper layer+rubber epoxy asphalt AC-10 lower layer,which could technically support for the deck pavement structure design of the same type bridge in China.Firstly,the aggregate gradation ranges of SMA-13 on the upper layer and AC-10on the lower layer were investigated and analyzed,and the optimal asphalt-stone ratios of SMA-13 and AC-10 were determined to be 6.17%and 6.54%respectively by the Marshall Test method.Considering the influence of the content of epoxy resin and curing agent on AC-10 asphalt mixture,the optimal content of 30%was determined by comparing the performance of high and low temperature of AC-10 asphalt mixture with different content.Then,the high temperature performance,low temperature performance,water permeability performance,water stability performance,fatigue performance and uniaxial compression performance of the upper and lower layers were evaluated by laboratory tests.Secondly,considering the characteristics of Jiangyin Yangtze River Bridge with long service time and large structural flexibility,it is necessary to overcome the limitations of local simplified finite element model.In order to study the mechanical response of the designed deck pavement under vehicle load,and to propose the optimal thickness combination of the upper and lower layers,this paper carried out the overall-local bridge finite element model of the designed deck pavement structure,which was based on the measured material parameters in the laboratory.In the whole bridge model under dead load and lane load,the bending moment of the main girder was taken as the control index,to determine the position of the most unfavorable girder section.According to St.Venant’s principle,the local bridge model was established to be a length of about 80 m along the longitudinal direction of the bridge.The most unfavorable condition of vehicle load was analyzed in the local bridge model.Then,under the most unfavorable vehicle load conditions,the optimal thickness combination for Jiangyin Yangtze River Bridge was determined to be 3.0cm upper layer+3.0cm lower layer.The influence of the shear capacity of waterproof adhesive layer on the mechanical response of the deck pavement was also explained in the local bridge model.Finally,in order to analyze the interlayer adhesive performance of the designed pavement structure,and to find the weak adhesive position and failure form of the whole structure,the deck pavement composite structure specimens with steel plate at the bottom were formed in laborary.Epoxy resin waterproof adhesive material and rubber asphalt adhesive material between the upper and lower layers were selected in the specimens.By the pull-out test,the variation of interlayer adhesive property with different content of waterproof adhesive layer was not considered obvious.And according to the failure specimens,the weakest adhesive locations were all located between the upper and lower layers,which indicated that the bonding strength of the used contents of waterproof adhesive layer was greater than the measured values.Therefore,when the content of epoxy resin waterproof adhesive layer is 0.2～1.1 kg/m~2and the content of rubber asphalt adhesive layer is 0.8 kg/m~2,the bonding strength of the whole deck pavement structure designed in this paper can meet the requirements of more than or equal to 1.80 MPa at room temperature.