Temperature Field And Rutting Analysis Of Composite Pavement Structure On New Type Steel Bridge Deck In Hot And Humid Area

The steel bridge deck paving structure not only affects driving comfort and driving safety,but also protects the steel bridge deck from load iMPact,spreads wheel load,and protects the bridge structure from environmental erosion.Due to the particular force of orthotropic steel bridge slab and the temperature sensitivity of asphalt mixture,the pavement structure is prone to diseases such as layer shift and rutting in the early stage of the joint effect of temperature and traffic load.This paper takes the new type of large longitudinal rib steel deck composite pavement structure "upper asphalt mastic macadam+lower ultra-high toughness concrete"adopted by Zhongshan Xihuan Lianshiwan Bridge as the research background.Firstly,the thermal physical parameters of the pavement materials are tested.Then the temperature field of the new composite pavement structure is analyzed by the finite element method,it provides the basis for the structural analysis and test of fatigue cracking,interlaminar shear failure and high temperature rutting.Finally,the rutting of the new steel deck composite pavement structure is analyzed by the finite element method.Firstly,the thermal conductivity and specific heat capacity of the materials used in the composite pavement structure are tested.The results show that at room temperature,the thermal conductivity of SMA-13 is 1.98 W/m · K,and the specific heat capacity is 1.014 J/g·℃;The thermal conductivity of UHPC with steel mesh is 2.80 W/m·K,and the specific heat capacity is 0.627 J/g·℃;At the same time,the influence of aging,porosity,dry and wet conditions on the thermal physical parameters of asphalt mixture is studied,the results show that the specific heat capacity and thermal conductivity decrease with the aging of asphalt mixture.The influence of different waterproof adhesive layers on heat conduction of pavement structure is analyzed,it is concluded that the blocking effect of epoxy resin on heat conduction is greater than that of SBS modified asphalt.Secondly,the finite element method is used to analyze the temperature field of the new steel deck composite pavement structure under three conditions of low temperature,normal temperature and high temperature,the results show that the temperature field of the pavement structure changes periodically as the ambient temperature,and the maximum temperature of the pavement layer in summer can reach 62.4℃ and lasts for a long time.Therefore,more attention should be paid to the high temperature problem in the design of the steel bridge deck pavement.By studying the influence of thermal parameters of pavement materials on the temperature field of new steel deck composite pavement structure under high temperature,it is concluded that the service condition of asphalt pavement under high temperature can be improved by increasing the thermal conductivity of upper and lower layers of pavement,increasing the specific heat capacity of upper and lower layers of pavement,increasing the emissivity of upper layer of pavement and reducing the absorptivity of upper layer of pavement.The temperature field results of the same steel beam form but different pavement structure,the same pavement structure but different steel beam form and the new steel deck composite pavement structure under high temperature are compared and analyzed,the results show that the open steel beam can significantly reduce the maximum temperature of the pavement structure,reduce the high temperature duration of the pavement structure,So as to reduce the risk of high temperature rutting and interlaminar shear displacement of pavement materials.Thirdly,the creep parameters of SMA-13 are obtained through uniaxial compression test.Combined with the temperature field analysis results under high temperature,the rutting finite element analysis model of pavement structure is established.The ruts of new composite pavement structures under continuous temperature and 60℃ are compared and analyzed.The rutting changes of the new composite pavement structure under different load positions and loads are analyzed,the results show that overload has a great influence on rut.The most unfavorable load in transverse direction appears in the middle of the two U-rib stiffeners.Based on the investigation results of the traffic volume in Zhongshan West Ring Road,the rutting depth of the new composite pavement structure is estimated and checked by using the finite element method.The results show that the rutting depth of the new steel deck composite pavement structure meets the requirements.