Experimental Study On Material Design And Performance Of Steel Deck Pavement SMA-10 Asphalt Mixture

The asphalt paving layer as an important component of the bridge shows a significant influence on the quality of driving and life expectancy of steel bridges,which could be attributed to its excellence of material performance.The steel bridge deck paving structures commonly used at home and abroad mainly include: pouring type and SMA,double layer SMA,double layer epoxy asphalt,double layer pouring type.Compared with poured asphalt mixtures and epoxy asphalt mixtures,SMA has the advantages of mature construction technology,easy operation,low cost,and convenient maintenance and implementation during operation.This paper focuses on the material design and mixture properties of SMA-10.From the two levels of raw material selection and material design,it improves its water tightness,deformation follow-up with steel plates and high temperature stability,and finally improves the durability of SMA bridge deck paving structure.This research,therefore,pays more attention to the asphalt paving layer of the SMA structure on the basis of the current research status of steel bridge deck surfacing technology.The main contents are as follows:(1)Raw material selection and testing.This part will focuses on the performance comparison of SBS modified asphalt and high-elastic modified asphalt which is consist of SBS modified asphalt and high-elastic modifier.(2)Research on the performance of the asphalt paste system of mineral powder.Comparing the high temperature and low-temperature properties of different mineral powders,the ratios of powder to rubber and modified asphalt pastes by the experiment of dynamic shear rheometer(DSR)and low-temperature bending beam rheometer(BBR).Analyzing the influence of mineral powder on the performance of asphalt paste(3)SMA-10 grade optimization and mix ratio design.This paper proposes a performance equilibrium mineral grading optimization design method with porosity and skeleton penetration intensity as indicators.In this paper,the Marshall volumetric design method is used to determine the optimal amount of asphalt for mineral gradation.(4)The research of SMA-10 road performance experiments.Through freeze-thaw splitting experiments and immersion marshall experiment,research the water stability of gradation,asphalt types(highly elastic composite modified asphalt,SBS modified asphalt),and asphalt mixtures with different ore powders.Through rutting experiments,research the effects of gradation,asphalt type and mineral powder on the high temperature performance of SMA-10 mixture.Through low-temperature trabecular experiments,research the effects of gradation and asphalt type on the low-temperature crack resistance of asphalt mixtures.The main research conclusions drawn in this paper including:(1)According to the test results of softening point,low temperature ductility,and needle penetration index.The high-temperature performance,low-temperature performance and temperature sensitivity of high elastic composite modified asphalt are better than SBS modified asphalt..(2)The composition and performance of the ore powder affect the high temperature and low-temperature properties of the asphalt ore powder paste.Compared with the type of ore powder and the powder-to-glue ratio,the properties of asphalt have a greater impact on the high-temperature performance of asphalt paste.The high temperature and low-temperature performance of high elastic composite modified asphalt paste are better than SBS modified asphalt paste.The anti-rutting factor of highly elastic composite modified asphalt paste is 3.91 times of SBS modified asphalt paste.The low-temperature bending creep strength value of the highly elastic composite modified asphalt paste is 24.9% lower than SBS modified asphalt paste.(3)For the protective layer SMA-10 asphalt mixture,the performance equilibrium gradation optimization design method is adopted.In the process of gradation optimization,the porosity and penetration intensity indicators are used to determine the coarse aggregate ratio of the skeleton and the amount of filling particles.(4)Compared with SBS modified asphalt,the high temperature stability and low temperature crack resistance of SMA-10 are significantly improved.The dynamic stability of SMA-10 is increased by52.50%,and the bending strain value of low temperature girder test is increased by13.01%.The experimental rules of high temperature and low temperature of asphalt mixture are consistent with the experiments of glue paste.(5)The low porosity SMA-10(its porosity is less than 3%)has strong water stability,crack resistance,and its high temperature performance is also at a high level.The research results of this paper have important guiding significance in the design and construction of asphalt pavement layers on SMA structural bridge decks.