Design And Performance Study Of Steel Bridge Deck PC-SMA Composite Pavement Structure

Polyurethane mixture,due to its superior high temperature,low temperature,and fatigue resistance property,can significantly extend the service life of pavement structures and is expected to become an excellent substitute for asphalt bridge deck pavement materials.However,if polyurethane mixture is used in both the wearing and protective layers of bridge deck pavement structures,on the one hand,its price is relatively expensive and it is not easy to promote;On the other hand,if the polyurethane mixture is used as a wearing layer,the defects of relatively insufficient water stability,wear resistance,and slip resistance are easily exposed.Therefore,this study proposes a new paving structure with polyurethane mixture as the protective layer and SMA as the wear layer.This structure applies polyurethane mixture to the protective layer,which can leverage its advantages of good following and fatigue resistance.Using asphalt mixture as the wear layer can avoid the weaknesses of poor water stability,wear resistance,and sliding resistance of polyurethane,and fully utilize the respective characteristics of polyurethane mixture and SMA.This study conducts mechanical analysis and road performance tests on this new type of pavement structure,and compares it with traditional bridge deck pavement structures to explore the feasibility of the new structure.Firstly,taking the Wuhan Baishazhou Yangtze River Bridge as the research background,a three-dimensional model of the steel deck pavement structure of the Baishazhou Bridge was constructed using the finite element analysis software ABAQUS.The loading was carried out in accordance with the bridge design specifications,and the load arrangement was carried out using a single wheel uniform distribution method to find the most unfavorable load acting area along the entire bridge direction.The maximum surface tensile stress and strain of the new pavement structure under different temperatures and loads were calculated and analyzed The mechanical responses such as bottom shear stress and maximum vertical deformation are compared with those of traditional pavement structures to reveal the influence of new pavement structure combinations on stress.The results indicate that an increase in temperature and load will have adverse effects on the pavement structure,and the magnitude of load is positively correlated with the mechanical response;The influence of different types of pavement structures on stress is different.Under the same temperature and load conditions,the surface tensile stress and bottom shear stress of the pavement structure with upper SMA and lower EA are relatively high,while the vertical deformation of the double-layer SMA and upper SMA+lower GA is relatively large.Secondly,conduct oblique shear tests and direct shear fatigue tests to analyze the effects of factors such as the type of adhesive layer material,coating amount,curing time,and temperature on the interlayer shear resistance,and recommend the most suitable interlayer bonding material.The results indicate that the selection of adhesive layer materials needs to be based on environmental conditions.For summer cooling areas,for economic reasons,choosing SBS modified asphalt as the adhesive layer material is sufficient to meet the usage needs;For hot summer and hot summer areas,choosing polyurethane as the adhesive layer material is more suitable;For areas severely affected by freezing and thawing,it is more appropriate to choose epoxy resin as the adhesive layer material.Finally,the PC-SMA pavement composite structure was subjected to composite plate rutting tests,composite small beam low-temperature bending tests,and composite small beam bending fatigue tests to evaluate its high-temperature stability,low-temperature crack resistance,and fatigue resistance.The results showed that both the PC-SMA pavement composite structure and the EA-SMA pavement composite structure had good high-temperature stability,The PC-SMA pavement composite structure has excellent low-temperature crack resistance and fatigue resistance.