Study On Repairing Technology Of Asphalt Pavement Surface Course In Chang-Ping Expressway

The Changchun-Siping expressway locates in Jilin Province, central region of northeast three provinces. It links to Shenyang, Dalian and other place inside Shanhaiguan in its south direction, and reaches to Harbin in its north direction. It's an important road segment of the highway from Tongting to Sanya in"two horizontals and two verticals"of the national freeway system layout planning,and also an important component of the"four verticals and three horizontals"highway main framework of 30 years road network planning in Jilin province. The total length of Changchun-Siping expressway is 133.26Kms, are designed with express standard of 4 lanes in two ways, fully-closed and fully-interchange. There are seven connection lines, with total length 23.611Kms, primary class automobile exclusive highway 7.156Kms and second-class highway 16.455Kms.Its surface course adopts 4cm AC-13, middle course adopts 5cm LH-25 II and bottom layer adopts 6cm LH-30 II. The base course adopts lime-fly ash concrete,the subbase course adopts lime-fly ash sand soil. There are perfect transportation safety device, the management facilities, service facilities, the charges system and supervision and corresponding system.The Chang-Ping expressway was conceived in 80's last phase. At that time after several years of reforming and opening, the speed of economic development of Jilin province is fast, among them the automobile manufacturing, chemical engineering etc. industry develop quickly. The need of the transportation for economy high speed development is more and more high, the Beijing-Harbin railway between Changchun and Siping had already been in saturation state.Because of the fast development of the economy and fierce increment of and traffic volume , 102 lines appeared not adaptability, great quantities of transit traffic volume crossed the towns.This project completed the establishment work of feasibility study report , environmental impact assessment report, schematic design documents in 1989 to 1993,and completed the construction drawing design word at the of aug,1993.On May 10 in 1994, the Chang-Ping expressway hold ceremonious opening ground breaking ritual,finish construction to be open to traffic formally on September 19 in 1996, thus ended the history of without expressway of Jilin province.In recent years, the heavier load of transportation, the channelization of transportation flow, the aggrandizement of the transportation density, increase of the speed, a lot of expressway's pavement using function has already started to gradually reduce, for example pavement distress, rapid deterioration of the load capacity and anti-slide performance, made Chang-Ping expressway can't provide a fast, safe and comfortable service for the vehicle gradually, And increased the operation cost of the vehicle, enlarged the risk of driving, shortened the usage time of pavement, affect the service ability of the road, obstruct the play of transportation benefits.Therefore, carrying on protect and repair to the pavement in time, and making the usage function of pavement recovered and improved can prolong the service life of the pavement, this not only provided huge economic benefits to highway management department, what's more important is providing guarantee for convenient highway user's traveling and promoting the society material circulation.Since 2003,the Chang-Ping expressway maintenance engineering adopted 5% SBS modified asphalt AC-16K(andesite crushed stones) in the surface course, adopted 3% SBS modified asphalt CY-20( namely AC-20Ⅰ)( limestone) in the underneath layer. It is discovered from one year construction practice that, parts of road segment still appears the ruts after maintenance (small than 5 millimeter).For resolving the problem of ruts eventually, In the beginning of 2004, the modification towards designing project are carried on again, the mineral aggregate gradation of the top, middle and bottom layer all adopt G structure (be partial to thick), and it is discovered from one year construction practice that, although the rut problems were reduced a lot, if the roller compaction is not enough and the segregation in the spreading , the road structure is easy to occur the phenomenon of water permeable.In the year of 2005, comprehensively considering high temperature anti-rut capacity, low temperature anti-crack performance, at the same time satisfying enduring, stability, bleeding, anti- slippery etc. request, adopt C AC-16 type match ratio design, produced a certain result, but still can't expel the occurrence of some latent problem in heavy carried transportation.To see from the present damaged condition of asphalt pavement, in addition to individual differential settlement because of roadbase, mostly are diseases produced in asphalt course, such as pit, flushing ,rut, net-shaped cracks and loosening.Since for the semi-rigid asphalt pavement, the semi-rigid base and the subbase are the main bearing course, the course are mainly have using function, , have no necessity to the basic level and in, underneath the layer carries on the processing, reducing from the economy thus otiose waste, also carried out the repair purpose that road face, thus guaranteed to go the car of safety, comfort. On the condition that the middle and bottom course are compacting, stable and fatigue resistant, there are no necessary to process the middle and bottom course, which reduced the unnecessary waste from the economy, also carried out the repair purpose of pavement, and guaranteed safety and comfort of driving. Therefore, fully play the using function of surface course and make sure a reasonable course structure is the quest that we want to explore.This paper aims at the breakage type of Chang-Ping expressway, puts forward the prevention measures to diseases of expressway asphalt pavement, based on analyzing the domestic and international asphalt pavement repairing technical, expounds existing asphalt pavement repairing methods, by indoor experiments to study the mineral aggregate gradation and road using performance of ultra-thin wearing course, puts forward mix proportion of the ultrathin wearing course, puts forward the construction technique and construction crafts by constructs trial road, lay a certain foundation for the expansion and application of ultrathin wearing course in asphalt pavement repairing.This paper bases on thorough research to ultra-thin wearing course and the trial road built in Chang-Ping expressway, and combines a great deal of spot examination, its main conclusions are as follows: 1.Ultra-thin wearing course repairing pavement technique has characteristics such as : low price ,long service life span , quickly open to traffic, quickly to spread, short work period, easily protecting.2.Good water permeability, ultra-thin wearing course as a kind of mixture which can mutually connect interspace, the void ratio can amount to 15%～25% , can provide drainage gallery when the rain is heavy, the rain water vertically passes wearing course and arrives the surface of underlayer, then discharges from the side the edge of pavement, to prevent the occurrence of fog phenomenon caused by vehicle.3. Perfect noise reduction effect, the low noise asphalt pavement eliminates the evacuation and compression of air at a large degree, so can reduce the noise.4. Good anti- slip performance, because of the rough surface, so not only under dry pavement condition, its anti- slip performance is higher than traditional asphalt pavement, but also under the wet pavement condition, the anti-slip performance has a big exaltation.5. High safety, because of rain water pass through ultra-thin wearing course, there are no continuous water film in the pavement and water accumulation in great quantities, thus can raise the adhesive strength between tire and pavement. If rain lasts long hours, may make OGFC saturated, but because of the water pressure of vehicle and tires can release through OGFC's bore structure, still won't occur water floating , and can reduce splashing and spraying, raising the visibility that driving in the rainy day.