Study Of Composite Pavement System On Orthotropic Steel Bridge Deck

Wearing surface on orthotropic steel bridge deck is a complicated yet still not well solved technical problem. Due to the great flexibility and large local deformation of orthotropic steel bridge deck, combining with the influence of the traffic, temperature, wind, earthquake and other natural factors, the stress and deformation of the bridge deck are very complicated, which leads directly to its pavement more complex and negative. The tensile, compressive and shear strength of asphalt concrete are relatively small, much more different from steel bridge deck. So the mechanical situation of the wearing surface is very complicated. Fatigue cracking, rutting, delaminating and other early damage are common. Obviously, it is quite difficult to solve the problem of wearing surface on orthotropic steel bridge deck with the traditional method.Therefore, the characteristics and requirements of the orthotropic steel bridge deck pavement are investigated and analyzed in the paper, based on technical exploration, theoretical analysis and laboratory tests. Given the unique advantage and great achievements of the steel-concrete composite structure in civil engineering, a new composite wearing surface system consisting of SMA13 wearing course and lightweight polymer cement mortar (LPCM) transition layer, is presented and studied theoretically and experimentally.Firstly, according to the investigation and analysis of the diseases in wearing surface over orthotropic steel bridge deck, main failure types appeared in service are concluded. And the corresponding design index are proposed, such as tensile stress of surface, shear stress between wearing surface and steel bridge deck, vertical compressive strain of the wearing surface, and shear stress of the wearing surface.Secondly, taking orthotropic steel bridge with stiffening ribs and vertical/cross slabs, and wearing surface on beam segment as calculation target, the typical wearing surface response is analyzed and determined. The relation between main design index and the modulus of transition layer or between main design index and the thickness of pavement is analyzed. Given the great achievements of the steel-concrete composite structure, a new surface system consisting of SMA13 wearing course and LPCM transition layer, is proposed. And the design and calculation method is presented, such as the thickness of the system and the structure of shear connectors.Thirdly, the materials is selected, graduation is design and marshall tests are carried out to design a high-performance SMA13.Then rutting test under high temperature, triaxial shear test, water stability test, and fatigue test are conducted to study the road performance of SMA13. And a trial road is constructed to study on structure and material of asphalt pavement under heavy load and high temperature under a project from Guangdong Provincial Communication Department. At the same time, acrylic latex was added into lightweight cement mortar, and mixture ratio is design. The bending strength, the compressive strength, the fatigue performance, the ultimate bending strain and the resistance to chloride ion permeability were tested. Then a lighter, rigid transition, excellent fatigue resistance and excellent bending performance LPCM is proposed, which is applicable to transition layer on orthotropic steel bridge deck. And the action mechanism shows that high-tensile strength of the polymer membrane is significantly improved LPCM mechanical properties.Fourthly, the stability between wearing surface and steel deck, within wearing layers, and the thermal compatibility and durability of the new wearing surface system under high temperature are experimented to investigate the temperature and intensity of the new system. The fatigue damage of four-point bending fatigue test process for SMA13 and LPCM is analyzed using a classic damage theory, Comparing the analysis results with the test results, the fatigue damage model was verified, and the prediction method of these two kind materials is developed. In addition, composite beam fatigue tests of the new composite system and the traditional double-SMA system are carried out, which shows the fatigue performance of the new system is better than the traditional one.Finally, based on the summary of the previous studies, the design method of the composite wearing surface system on the orthotropic steel bridge deck was discussed in the paper. And the control index and checking index of the new system on orthotropic steel bridge are proposed.