| The steel deck pavement technology is one of the key technologies of long-span bridge construction and operation and maintenance which has been attached great importance and concern by the academia and engineering sector of domestic abroad. At present, the main pavement on orthotropic bridge steel deck are double-SMA type, Guss asphalt type, Epoxy asphalt type, Polymer concrete type and the combinations type around the world, especially the epoxy pavement type performed better on numerous orthotropic bridge steel deck with high temperature,heavy traffic. Epoxy asphalt mixtures is an excellent pavement material with excellent resistance to high temperature, high toughness, good performance to anti fatigue, especially it can adapt to heavy traffic better. However, the investigation showed that part epoxy-asphalt pavements appear poor skid resistance at the early time, and epoxy-asphalt mixtures tests and construction are lack of test evaluation methods and specific technical standards which were reference the bituminous mixtures. In order to solve the problems, we optimized the gradation of epoxy asphalt mixtures to improving the design methods of epoxy-asphalt mixtures and evaluating the compaction characteristics and regularity of epoxy-asphalt mixtures.Asphalt mixture gradation, porosity and compaction characteristics, pavement surface texture and durability influence each other. Void ratio is the key control index of compaction of mixtures. In order to evaluate the influence of porosity on epoxy asphalt mixture performance, firstly, combining with tensile strength of epoxy-asphalt, the splitting strength of epoxy-asphalt mixtures before and after freeze-thaw cycles and the fluorescence photomicrographs and SEM photomicrographs of epoxy asphalt and epoxy-asphalt mixtures, to investigate the damage mechanism of mechanical properties of epoxy-asphalt mixtures with high air voids(>3%)under freeze-thaw cycles.By the Fluorescence Microscopy and the Scanning Electron Microscopy, the microstructures of the epoxy-asphalt and epoxy-asphalt mixtures after freeze-thaw cycles were investigated. Then study on the performance of the epoxy-asphalt and epoxy-asphalt mixtures under freeze-thaw cycles by tensile tests and freeze-thaw splitting tests. The results show that: the bitumen particle which in the micstructure of epoxy-asphalt had moved together, the tensile strength of epoxy-asphalt declined 23.9% and the splitting strength ratio of epoxy-asphalt mixtures was 69.8% after freeze-thaw cycles.In order to improve the skid resistance and fatigue resistance of epoxy asphalt mixture, proposed the design methods which were coarse gradation epoxy-asphalt mixtures and rich epoxy-asphalt mixtures. The performances of Marshall Stability, trabecular bending, water stability and fatigue resistance of two newly epoxy asphalt mixture were comprehensively compared and evaluated. The performances of two newly epoxy asphalt mixture were analyzed comparatively with traditional gradation epoxy asphalt mixtures. The results showed that the coarse graded epoxy-asphalt mixtures could improve skid resistance, while its flexural tensile property, marshall stability and water stability did not change significantly; rich epoxy-asphalt mixtures enhance deformation property greatly, the fatigue performance of the rich epoxy asphalt mixtures is the best, the type I coarse gradation epoxy-asphalt mixtures is the second, the traditional gradation of epoxy-asphalt mixtures is the lower.Compaction characteristics of epoxy-asphalt mixtures with different gyration compaction numbers, temperature and gradation were studied by SGC. At the same time, the difference of compaction curves of A-90, A-70, SBS modified asphalt and epoxy asphalt was also compared. In addition, the molding method of compaction molding, wheel roller compaction and rotary compaction were compared. The results showed that the compaction property of epoxy-asphalt mixtures was different from that of bituminous mixtures, and the compaction curve obtained by Marshall compaction was significantly different from gyration compaction. The compaction curve obtained by wheel roller compaction and gyration compaction was similar.In the end, this paper made an engineering applied research based on Jiangshun bridge steel deck pavement project. Optimal design gradation of epoxy-asphalt mixtures compacting technology had been tested study, and analyzed the coarse graded epoxy-asphalt mixtures of construction technology, providing a reference for grading design and construction control of epoxy-asphalt pavement.Research shows that: the larger void in epoxy asphalt concrete is not suitable for steel bridge deck pavement, which easily unboiled water damage problem of durability. Based on this, put forward type I dense and coarse gradation epoxy asphalt concrete which can improve skid resistance and the fatigue performance is better than traditional grading of epoxy asphalt concrete. The compaction law of epoxy asphalt concrete was studied by SGC test, and the construction technology of epoxy asphalt mixture with coarse gradation was summarized and analyzed. |
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