| Due to its beautiful appearance and strong bearing capacity,the construction of steel box girder bridges on important urban intersections is gradually rising.However,compared with large highway steel bridges,the research on the pavement of small and medium-sized steel bridges has not received enough attention.The direct transplantation of large cross-border steel bridge pavement is insufficient in economy and function.Based on the Xiaozhuang overpass steel bridge pavement project of Nanjing Hongshan Road rapid transformation project and based on high-performance polymer modified asphalt,this paper establishes a double-layer modified asphalt mixture pavement system suitable for the pavement of small and medium-sized span steel bridge surface,so as to meet the pavement performance requirements and achieve economic benefits at the same time.Firstly,ABAQUS finite element software is used to establish three-dimensional solid finite element models based on the main bridge and ramp of the actual project to study the temperature field and mechanical response of small and medium-span steel box girder bridge deck pavement.Based on the study of the most unfavorable load position,this paper analyzes the influence of pavement modulus and thickness,longitudinal and transverse load and bridge span on the mechanical response of pavement,and studies the temperature field of pavement periodically varying with temperature in adverse seasons under different environmental conditions,so as to clarify the structural design requirements of steel deck pavement of medium and small spans and give reasonable structures and parameters.Secondly,according to the characteristics of wearing course and protective layer of bridge deck pavement,the cement is optimized and the mixture is compared to study the road performance of single-layer pavement materials.Three kinds of polymer modified asphalt,high-strength asphalt and cast-in-place asphalt,are selected.The high-temperature,low-temperature,fatigue and micro properties of the three kinds of asphalt are compared through temperature scanning test,multi stress creep recovery test,bending beam rheological test,linear amplitude scanning test and infrared spectrum test.The results show that the high-temperature,low-temperature and fatigue properties of high-strength asphalt are better.SMA-13 mixture is designed.After comparing the high and low temperature performance of high rubber asphalt and high strength asphalt mixture through rutting test and trabecular bending test,high rubber asphalt SMA-13 mixture with better performance is finally selected as the wearing course.The oil-rich low porosity mixture is designed with high glue asphalt as binder and AC-10 and CAM as gradation.Compared with the pouring asphalt mixture,the high glue asphalt ac-10f mixture and high glue asphalt cam mixture with relatively balanced high temperature and low temperature performance are finally selected as the protective layer.Uniaxial dynamic creep test and dynamic loading semicircular bending fatigue test were carried out for the selected three mixtures to verify their high-temperature viscoelastic properties and medium temperature fatigue resistance.Finally,through the research on the bonding performance,deformation performance and waterproof performance of the waterproof bonding layer,it is determined to use Japanese epoxy as the waterproof bonding layer,with the dosage of 0.5kg/m~2.With the pavement structure of4cm upper layer and 3.5cm lower layer,the high temperature performance and fatigue performance of the pavement system are verified by rutting test,dynamic creep test and improved five points composite beam fatigue test.The results show that with high rubber asphalt as binder,SMA-13 grading as wearing course and oil-rich ac-10f and cam as protective layer,the high temperature and fatigue performance of the structure can meet the pavement requirements.Among them,CAM as protective layer has better high temperature performance and AC-10F as protective layer has better fatigue performance. |
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