Application Study On SMA Base Of Ji-Liao Expressway Heavy Maintenance

With the rapid development of the national economy, increasing road traffic, axle set is also increasing, drainage and road traffic on the increasingly high demand, high-temperature rutting, low temperature brittle fracture, poor performance against sliding disease a serious impact on the quality of the asphalt concrete road. SMA is a by asphalt, fiber stabilizing agent, slag, and a small amount of the fine aggregate composed of asphalt Matrix lipid-filled intermittent, with a mixture of asphalt. It is the basic component of crushed stone and Matrix asphalt two part. Because SMA is fully consider the widespread use of the AC, AM and AK levels with the advantages and disadvantages, and to use their advantages, thus improving their overall performance, such as anti-slide, down impatient, impervious and durable, reducing maintenance costs, Extend the service life of 30% to 40%. It can be said that this is new asphalt surface or surface highway Overlay preferred direction of development.The first chapter of this paper introduced the purpose of the study and research conditions at home and abroad. Ji-Liao for highway traffic, overloading of vehicles, the characteristics of major axis, while the road design thickness too small, the overall strength of inadequate road structure is irrational; caused a road rutting, vertical and horizontal cracks and the destruction of poor performance against sliding . SMA through the SBS modified bitumen road and overhaul of the application of the new structure to address the above issues.Chapter two of Ji-Liao expressway carried out a detailed road disease survey, the main diseases are cracks and rutting. Some sections of the coring, the formation of the road, deflection, and the lateral force coefficient was detected, and the road from the structure and factors outside influence on the road causes a disease in-depth analysis, pointing out that the need for overhaul .The third chapter deals with the SMA design and performance studies. SMA modified asphalt mix design, using Marshall Volume, to 4.75 mm sieve as the key sieve, was chosen by 24% and 27%, 30% three grades, with design, identified three kinds of mineral aggregate gradation. By the initial commissioning of the three-graded, in accordance with the relevant tests determined the SBS modified asphalt compaction temperature (for laboratory samples at the scene and forming the initial temperature RCC) to 165℃, double-sided hit it 75 times for the Marshall specimen Molding, each graded by asphalt content 5.5,6,6.5, respectively Marshall specimen molding. And the Marshall indicators were tested by the three-level with the comparative analysis of experimental data, to determine the optimal allocation for the aggregate level one with the best asphalt content of 5.9%.The fourth chapter is the research of the new road structure in Ji-Liao expressway heavy maintenance.(1) Pavement structure level combination is more reasonable. SBS on modified asphalt SMA the surface layer and SBS modified asphalt AC-20I use the modified asphalt, The softening point amounts to 79.5 degrees Celsius; Melts the basic unit to use the MAC asphalt, the softening point amounts to 71.2 degrees Celsius. The SMA bituminous mixture wheel rut dynamic stability achieves 4062 times /mm, anti-wheel rut ability obvious enhancement.(2) Additionally builds LSPM in the semi-rigid basic unit, has the draining water performance well, the intensity high, prevents the reflection crack, more suitable heavy transportation need. Had considered draining water and the waterproof design, reduces the pavement structure level the pounding destruction.(3) increased the graded broken stone excessively level, played draining water, had prevented the crack the role, in its under and supposed the calcareous soil to go down to the basic unit, selects material combination which various structures level the module decreased progressively gradually, caused various structures level stress to be more reasonable.The fifth chapter elaborated has aided chats road lying with the examination. Aids chats the high speed construction craft to have strict to have to include the blend the transportation, spreads paving with the roller compaction, the quality control. The roller compaction is especially important, the concrete step is:Under the pilot defined in paragraph structure, we do not use the early pressure, rehabilitation pressure, Final pressure RCC three phases. Bicycle use DD130 two vibratory roller, at the same time, beginning with a vibratory roller in high-temperature state of RCC vibration, temperature not lower than 160℃; not less than 3 to 4 times compaction coherent, ending a temperature not RCC less than 130℃. Vibratory Roller follow "keeping up, slow pressure, high frequency, low amplitude" principle, the compaction rate not more than five km / h. It has been observed that SMA mixture under high temperature compaction, without passage of such instability. On the edge, bridges and major joints such as the use of the site inaccessible mechanical vibration BMW rammed solidified.After project completion, carries on the examination, the examination result indicated that, uses the SMA surface layer, has the fine smoothness and the anti-slippery performance, enhanced the driving comfortableness, simultaneously the outstanding deflection value enhanced the road surface overall intensity.The sixth chapter is the conclusion with further studies the tentative plan, completed the research work to the paper which in the process did to carry on the summary, also proposed also had to continue in the work to conduct the research the content and the direction.