Research On Structure Of Asphalt Overlay On Old Cement Concrete Pavement And Materials Of Stress Absorption Interlayer

With the rapid development of China's highway transport industry,many of cement concrete pavement which constructed in the early appeared a large variety of diseases,maintenance cost is increasing year by year,The pavement performance has been unable to meet the people's demand for travel,it is urgent to upgrade the old cement concrete pavement.Old cement concrete pavement asphalt mixture layer is a relatively common type of transformation in recent years.It is an economical and effective method to transform the remaining structure bearing capacity of old cement concrete pavement in the same time with the advantages of asphalt pavement smoothness and comfort.But at the same time,this kind of structure can not avoid to solve the problem of preventing and controlling the reflection crack.In all kinds of measures of preventing reflection cracks,setting modified asphalt mixture material stress absorbing layer as anti cracking interlayer is a effective method.This paper through the old road condition survey in Nantan Highway reconstruction project found that main diseases including pavement cracks?plate angle fracture and crushing plate,and through exacting pavement PCI,the rate of broken plates,transfer of joint bearing capacity and pavement bearing force detection found that using status of old cement concrete pavement has not been able to satisfy the design period cumulative traffic volume requirements,it must through pavement modification to improve the bearing capacity of pavement and improve durability.At the same time,through the comparison of the anti reflective cracking scheme and the surface layer of asphalt structure,and combined with the example of the internal and external reconstruction in Guangxi province,a kind of structure scheme is recommended.Based on the highway pavement survey data of Nantan,using finite element software to establish the model of pavement structure,under traffic load and temperature load condition,analyzing the force influence law of pavement structure layer by traffic load,paving layer thickness and modulus and stress absorbing layer thickness and modulus.The results of the comprehensive analysis suggested that the reasonable thickness and modulus of asphalt overlay that based on stress absorbing layer and the stress absorbing layer were recommended.From rubber asphalt rubber mesh and content,aggregate performance requirements,to study the rubber asphalt mixture ARAC-10 stress absorbing layer gradation design and the optimal asphalt content.In consideration of the stress absorbing layer mixed material high temperature stability,flexural tensile strength and workable performance,when the dry density is maximum,asphalt-aggregate ratio is lower limit.The asphalt-aggregate ratio which Schulenburg Binder Drainage Test loss rate correspond to as the upper limit and through the optimal performance of road to determine the stress absorption layer optimal asphalt content.Eventually the Oil-stone ratio of the stress absorbing inerlayer was 7.2%.Finally through rutting test,low temperature bending test,water stability test and fatigue test to study high temperature performance,low temperature performance,water stability and anti fatigue performance of the stress absorption layer material.The test results show that: stress absorbing layer material(ARAC-10)has excellent pavement performance,it can effectively delay the occurrence and development of reflective crack.