| According to the existing Specifications of Pavement Design in our country, for bituminous concrete pavement , the service life of Freeway Pavement and first class highway is 15 years ,and the first class highway is 12 years. However, with the development of economic, the sharply growing traffic volume and vehicle load, some not quite reasonable pavement design, and the poor construction quality are causing the damage of pavement, the service performance of pavement is constantly decreased, and pavement built formerly have reached their service life, some new pavement have appeared various degree of damage when far away to their design life, so the early damage of freeway pavement can't be ignored. Although the freeway adopts thicker asphalt surface course, stronger base course, there still are problems like cracks, rutting, quick attenuation of flatness and skid resistance, which are even more serious than first class highway and second class highway. Take Chang-Ping freeway as an example, its span is 133.255km, it was completed and opened to traffic at Sep.19, 1996. According to the investigation of the road situation in 2006, the present condition of Chang-Ping freeway isn't optimism: the area of chap is 42300 square meter, net-shaped cracks 86560 square meter;the depth of single rut is 37360m ,the length of rutting accompanied with chap and net-shaped cracks is 22050m,partial pit groove and joint pit groove 240 square meter, frost boil 9196 square meter.These diseases all directly affect the safety and comforts of vehicle driving, however we haven't quite understood about a series of problem such as the reason of pavement diseases, destructive mechanism and maintenance countermeasure. When we pay attention to build new altitude highway, we haven't think much of pavement maintenance. We can predict that in the near future, after our country's high grade highway construction obtain a stage result, our emphasis would transfer gradually from building to the repair and maintenance of the existing highway .Aim at the creation of various disease of all levels highway asphalt pavement, how to adopt an effective prevention and cure measure , choose a fitting and reasonable pavement maintenance means, and help basic maintenance branch to handle the pavement diseases in time and efficiently becomes a very urgent problem that we faced.According to analysis of the domestic and international data, the breakage of asphalt pavement can be divided into two major types, which is structural breakage and functional breakage. The structural breakage because of the decrease of loading capacity of each layer of pavement , the reflection of its result to the pavement surface are cracks of various shape, such as the horizontal cracks and lengthways cracks, chap andå—裂etc.. The factors of the creation of these cracks are a lot, including the sinkage of roadbed, the bad quality of pavement material, the disqualification of construction quantity, the water seepage, and the shear action of vehicle load and so on. The functional breakage is because of the abrasion of road surface and the aging of material and the like, its performance is the service ability of pavement becoming decline, the reduce of flatness, decline of skid resistance ability and deepening of the rut .The familiar functional breakage includes partial crack, lengthways surface roughness, rut, bridgehead jump, pit, flushing oil, wave and so on.When it comes to the last century 80's middle, the speed of building new highway in foreign developed country tends even slow, the highway maintenances becomes the point of highway branch's work. The crack filling and pothole repair become the most familiar daily maintenances work, and get the concerned department's attention no matter in the domestic or abroad.Currently the crack filling material which is widespread adopted and can be divided into three types. The first is the heat impletion rubber bitumen , which is extensive adopted because of its low price and not strict request to the builder. The second is silicone resin, which is mostly used to seal the joint of new constructed concrete pavement because of its high viscosity,difficult inleakage to crack,high request to the construction condition,time-consuming and expensive. The third is cool impletion filling material, whose basic substance is emulsification bitumen,and its limit condition is less and can be used without heating, so it can be used in dank and dusty pavement .The pothole repair is mainly repair and strengthen to the disease such as pit and groove, partial net crack ,chap and so on ,and at the same time can repair local sink , upheaval and slippage crack and other diseases. There are many concrete pothole repair methods, heat reinforcing method,gunning process,heat regeneration method are all below to traditional repair methods, and LB pavement repair technique is a new arisen methods.Combining the actual project Chang-Ping freeway, this text mainly does the following research works:(1) Investigating typical diseases of the Chang-Ping freeway, analyzing the reasons of those diseases;(2)Comprehensively considering high temperature anti-rut ability, the low temperature crack resistance, at the same time satisfy the request of durability, stabilization, bleeding, anti- slippery etc., put AC-16C asphalt mixture into the use of Chang-Ping freeway repair;(3) Thoroughly analyzing asphalt mixture structure constitute and graded theory,study mechanics function of the single material of AC-16C asphalt mixture, and determine a reasonable mineral aggregate gradation of AC-16C asphalt mixture.(4)Testing the high temperature stability of mixture by rutting test,and the stability of water by immersion marshall and freeze thaw split test , the anti- freezing by freeze-thaw splitting test, then evaluating the road use performance of AC-16C bituminous concrete;(5)Applying the asphalt mixture to the maintenance project of top layer of the pavement of Chang-Ping freeway, examining the application effect of AC-16C asphalt mixture in practical project .
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