Study On The Bridge Deck Pavement Technology Of Large Span And Low Tower Cable-stayed Bridge Cantilever

Large span, large cantilever Extradossed Bridge cantilever plate stiffness is relatively small, the web and stiffer have relatively larger rigidity,the stress of the concrete box girder and steel box girder bridge is similar, with large deformation, easy to cause cracking in the middle of the cantilever platebridge deck, so large span, large cantilever Extradossed Bridge deck pavement technology is one of its key technologies.Gussasphalt deck pavement has good deformation ability, good integrity, with excellent resistance to low temperature cracking, fatigue cracking and deformation from recovery. But because of the high temperature performance of modified asphalt, recover from deformation and durability insufficient, serious damage appears soon after the opening of the deck. On the basis of the existing domestic and international research, conbining Shiwan Bridge construction project in Foshan, analysing mechanical characteristics of Shiwan bridge deck pavement deeply and systematically, using TLA + SBS modified asphalt and adding complex basalt fiber, conducting a research on TLA + SBS modified asphalt concrete composite bridge deck TGAC mix design, road studied performance, construction technology and construction quality control methods:1. The most unfavorable position of Shiwan bridge deck pavement and stress control indexThrough the establishment of large span and large cantilever cable-stayed bridge deck composite pavement system model, using the three-dimensional finite element method to analyse the mechanical response of bridge deck pavement, in order to determine the most unfavorable position of vehicle and the stress control index of pavement layers. On this basis, put forward SBSAC-13 C modified paving mixture and TGAC-10 modified paving mixture technical indexrequirements, and aquire the fatigue life prediction equation of TGAC-10 modified paving bottom layer.2. The composite material of TLA + SBS compoundmodified asphalt optimizationThrough thirteen kinds TLA content of TLA + SBS modified bitumen compound were tested, obtained TLA + SBS compoundmodified asphalt softening point, equivalent softening point, penetration, penetration index PI, extension force TLA and other content with the variation to determine the optimal ratio of TLA + SBS modified asphalt composite proposed technical performance requirements TLA + SBS modified asphalt compound. For TLA + SBS modified bitumen microscopic properties of composite test revealed modification mechanism TLA + SBS modified asphalt compound through. 3. Research on the composition optimization of TLA and SBS compound modified asphalt concrete mixtureThe grading range of TLA and SBS compound modified asphalt concrete TGAC-10 of 9.5mm nominaldiaeter was designed. By using the TLA and SBS compound modified asphalt of five different TLA dosage(0%, 20%, 30%, 40%, 30%), Marshall test mix proportion design for asphalt concrete AC-10, SMA-10 and TGAC-10 was carried out respectively and its comparative study of road performance was made.Itconcluded the change rule of road performance index of various kinds of asphalt concrete with the TLA content,determined the target mixture ratio of the TGAC-10 which satisfied the requirement of bridge deck road pavement and put forward the technical requirements of TGAC-10 that used in the bridge deck pavement of Foshan Shiwan Major Bridge.4. The quality control indicators and method of the bridge deck pavementwith TLA and SBS compound modified asphalt concreteBased on the result of inside and outside experiment and entity engineering,the construction technology and construction quality control technology of bridge deck pavement with TLA and SBS compound modified asphalt concrete TGAC-10 were studied, construction technical guidance and quality control standard of bridge deck pavement with TLA and SBS compound modified asphalt concrete TGAC were proposed.5. The use performance of bridge deck pavement of TLA and SBS compound modified asphalt concreteThe TGAC bridge deck pavement of TLA and SBS composite modified asphalt concrete was longitudinal observation, and the performance in service such as PFWD modulus, roughness, compactness, rutting were detected. It was found that the production mixture proportion of the lower pavement with asphalt mixture TGAC-10 was controlled strictly and the requirement of quality control was meet. It also had excellent performance, meet the requirement of construction control and had remarkable economic and social benefits.