| Nowadays with the rapid development of social and economic in China,expressway construction has been at the stage of high-speed development.Expressway surface transforms from cement concrete pavement to asphalt concrete pavement.Due to the rapid increase of traffic volume and influences of various environmental factors,asphalt concrete pavement is usually in a state of overload,emerging many early diseases.If these diseases are not disposed timely,which will direct impact on the service level of expressway and cause huge economic losses.Therefore,expressway daily maintenance should deserve more attention and the research of overlay which is an important way for maintenance has great significance.Based on the maintenance project for overlay in Hangjinqu expressway,this thesis collects maintenance plan and achievement from year to year,investigating the pavement disease along the whole line and making test and giving comprehensive evaluation and analysis for current road condition,putting forward two thin overlay maintenance plans for those pavements at different maintenance stages(initial maintenance,finished first overlay)and at different maintenance position(mean line,ramp,inner square and outside square of toll station).Materials of the two maintenance plans are 4.5cm and 5cmAC-16C modified asphalt concrete and 2cm NovaChip ultra-thin wearing course respectively.This thesis tests raw materials performance of two pavement overlays,finishing mix design with Marshall design method and ensuring reasonable aggregate blending results:diabase(10?19):diabase(4?6mm):stone chips(0?4mm):mineral powder,which equal to 36.0:23.0:4.0:33.0:4.0;and the screening results of NovaChip:diabase(5?10mm):manufactured sand(0-3mm):mineral powder,which equal to 74.5:21.5:4 and the best bitumen aggregate ratio are 4.7%and 5.0%.Those mixed compositions are stirred respectively to make two finished mixture,all performance indexs of which are tested to gain the results which both meet the standard requirements.Finally,the thesis puts forward disposition for asphalt pavement diseases and construction technology and method for overlay,paving respectively 736m and 860m test road and choosing six mileages of text road to make quality evaluation,testing their thickness,compactness,permeable factor,BPN,coefficient of loose paving material and porosity and so on.These tested results are all meet the requirements,which ensures the safety and quality finishing of engineering project.Through systematic research,the thesis forms an integrated maintenance technique for overlay,which can prove basis for further application for maintenance technical application in Zhejiang area and use for reference for other similar engineering projects. |
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