The Technique Research And Application On Bituminous Concrete Thin Over-layer

At present, it is hardly for us to apply bituminous concrete over-layer on the old pavements due to the antinomies between lacking of the petroleum resources supply , the high-quality asphalt price soars rapidly and our highway construction, short of restoration funds , owes money heavely in the history. Weighing all of the condition and factors , reducing the thickness of the over-layer seems to an unique decent choice.Once this technique expands successfully,it will alleviate the our highway investment pressure ,speed the progress of high grade highway upgraded, change the structure of restoration, push the development of highway transportation science and technology.So it is an important event that benefits our country and our people. As for the thin asphalt pavement structure , mainly means the anti- slipped fiction course that used in the new construction or old pavement restoration. According to the thickness of bituminous concrete,it can be devided into thress types: thin bituminous concrete over-layer(25mm~30mm), very thin bituminous concrete over-layer(20mm~25mm) and ultra-thin bituminous concrete over-layer(15mm~20mm).The important and difficult event in bituminous concrete over-lay is how to improve the water-steady performance of bituminous structure and reduce and prevent from reflective cracking. Therefore, international scholars in the highway engineering field have done great quantities related research focus on the topic of defending cracking and anti- cracking.This paper bases on above research. Firstly ,Combining with"the ultra-thin bituminous concrete over-lay applied in the rehabilitation project of 321 Road in Zhao Qin"uses BISAR program to analysis the stress,strain, displace and energy which produced in the over-layer detailedly.At the same time, studying the influence on these variables which change material and load parameter.Thereafter, analysising the mechanism which load-type reflective cracking and temperature-type reflective cracking produce and develop respectively, and occording to different project demand ,propound related anti- cracking measures and estimate these measures. Besides, adopting the theory-analysis method, from the design theory, the design standard, the design parameter, making some resrearches on ultra-thin over-layer design method, putting forward various design rule which accommodate different anti- destructed demand in pavement.Lastly, testing the modified asphalt performance named Superflex which come from Indonesia and adopting LASTIKA graded in the testing road.After tracking the performance of the testing road,finding some problems in construction and putting forward some reasonable proposes.