| Has the world’s largest highway network in our country,by the end of 2019,the national highway maintenance mileage reached 98.8% of the total mileage,national large sums of maintenance and maintenance funds every year,according to the goal of construct ion of traffic power and the demand of the construction of a new generation of high-performance road,long-life pavement technology is the inevitable choice of pavement technology development in our country in the future.The ultra-thin overlay is a kind of maintenance material which can effectively improve the functional performance of road surface.It meets the requirements of "environmental protection,low carbon,energy saving,emission reduction,noise reduction" road advocated by the state,and has a good application prospect.Due to the high requirements for mechanical properties of ultra-thin overlays,ordinary asphalt ultra-thin overlays are prone to disease between pavement structure layers and overlay layers during service(mainly manifested as ag gregate falling,delamination,slippage,reflection cracks,et al.),which seriously affects the service level and service life of the road surface.Epoxy asphalt,as a kind of thermosetting material with long life,has excellent bonding,shear resistance,high temperature and fatigue resistance.In order to reduce the cost of life cycle and pave the pavement with high performance and long life,the research group proposed to apply epoxy asphalt material to the interlayer and surface layer of the ultra-thin coating to meet the higher mechanical performance requirements of the ultra-thin coating.In order to analyze and evaluate the interlayer and surface performance of epoxy asphalt ultra-thin coating,the road performance,fatigue performance,anti-reflection crack performance and interlayer bonding performance of epoxy asphalt ultra-thin coating mixture were systematically tested and analyzed in this paper.In addition,combined with the chemical modification characteristics of epoxy asphalt mixture and the construction process characteristics of epoxy asphalt mixture "post mixing method",indoor simulation test research was carried out for the key links in the construction process.Finally,the research results of this paper are applied to engineering prac tice.The main research results and conclusions are as follows:(1)Conclusions on road performance performance: The Marshall stability of epoxy asphalt SAC-10 mixture reached 85.08 k N,the immersion residual stability ratio is 96.4%,the freeze-thaw splitt ing strength ratio reaches 83.9%,the dynamic stability reached 55090 times/mm,low temperature tensile strain is 3012 με,the flexural tensile strength is 6.02MPa;assuming that the design traffic volume is1×108,the tensile strength structural coefficie nt of epoxy asphalt SAC-10 mixture is 2.18,and the tensile strength structural coefficient of SBS modified asphalt SAC-10 mixture is 4.82,that is,epoxy asphalt the structural coefficient of tensile strength of the mixture is only 45% of that of ordinary asphalt.explains that epoxy asphalt SAC-10 mixture has high strength,good resistance to water damage,high temperature stability and low temperature crack resistance,and good fatigue resistance.it is a long-life road surface material with superior per formance.It uses epoxy asphalt mixture.When the material is used as the asphalt paving layer,the thickness of the paving structure layer can be greatly reduced.(2)Conclusions on the bonding performance between cement concrete panels and epoxy asphalt ultra-thin overlays: This type of pavement structure has strong interlayer bonding performance.under different test temperature conditions,the optimal amount of epoxy asphalt bonding material is different;the loading rate has a great influence on the sh ear strength.The shear strength of the composite specimens of the two asphalt bonding materials increases with the increase of the loading rate;after immersion damage and long-term aging,the bonding performance of epoxy asphalt bonding material is signi ficantly better than that of SBS modified asphalt,and after long-term aging,the interlayer bonding performance of epoxy asphalt bonding material increases instead.(3)Conclusions on the bonding performance between asphalt concrete base layer-epoxy asphalt ultra-thin overlay layer: This type of pavement structure has strong shear strength between layers.aiming at this pavement form,compared to the cold bonding non-bonding material construction process,the use of thermal bonding technology or sprinkling of epoxy asphalt bonding material will significantly improve the interlayer shear strength of the pavement,but the thermal bonding construction process is not the increase in shear strength between pavement layers is more effective;under the same interl ayer treatment method,when the ultra-thin surface gradation is SAC-10,the interlayer shear strength of the pavement is the largest,followed by AC-10,and SAC-13 the smallest.It is better to use either of the thermal bonding process and the spraying of epoxy asphalt bonding material to improve the shear strength between the layers of the composite pavement at the same time.(4)Conclusion on anti-reflective cracking performance of epoxy asphalt ultra-thin cover: 0.135 mm is recommended as the target displ acement value of epoxy asphalt mixture OT(Overlay Tester)test;compared with SBS modified asphalt mixture,epoxy asphalt mixture has excellent anti-reflective cracking performance.the effect of freeze-thaw damage on the crack resistance of the two aspha lt mixtures is greater than that of long-term aging;for the maximum load-period curve,the epoxy asphalt mixture conforms to the change law of logarithmic function,while the SBS modified asphalt mixture conforms to the power function change law.(5)Combining the material characteristics of epoxy asphalt mixture and the process characteristics of epoxy asphalt mixture "post-mixing method" construction process,the on-site preparation of epoxy asphalt B component mixture,epoxy asphalt mixture on-site roll ing,epoxy asphalt A component addition amount,mixing work,curing time,B component storage time and retention time,etc.,carried out indoor simulation test research,detailed analysis and summary of possible problems in the process of engineering pract ice,for the construction of epoxy asphalt ultra-thin surface the corresponding measures are proposed for real-time control and construction quality assurance.(6)Taking yunnan wutangxun expressway(wuding-dangdian-xundian)luquan No.1 tunnel right asphalt pavement project as a physical application,the research results of this paper are used in engineering practice. |
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