Analysis And Evaluation On Reflection Cracking Prevention Of Interlayer For Recycled Cement Stabilized Course

In the process of large-scale road construction,a great quantity of semi-rigid base pavement is bound to produce a large number of milling materials.To alleviate the shortage of mineral resources at the present we can apply the waste materials to the new road.The strength and road performance of recycled cement stabilized course pavement are very good,however,due to the waste base material's high variability and high water absorption rate,the ability of anti-reflective cracking is worse than the ordinary semi-rigid base pavement.It can be seen that if we can take measures and more in-depth study to solve the reflection crack problem of the recycled cement stabilized course pavement,it has a very important significance to improve asphalt pavement function and prolong its service life.First of all,this paper determines the resilience modulus of recycled cement stabilized course,and uses the finite element software ABAQUS to simulate the real situation of the recycled cement stabilized course,then establishes the pavement structure model.We analyzed the stress at the bottom of the surface layer under different pavement parameters which is providing reference for structural design of the recycled cement stabilized course pavement.The results show that the influence of the partial load on structural is more serious,and the most unfavorable load position is under partial load.The main stress and the maximum shear stress at the bottom of the surface layer can be significantly reduced by increasing thickness of the layer under partial load,and the deflection of the surface layer will gradually decrease,too.However,the effect of reducing the stress concentration at the bottom of the surface layer is decreases gradually after the surface thickness exceeds at certain range.The increase of the surface layer modulus makes the stress concentration at the bottom of surface more serious;The maximum shear stress at the bottom of the surface layer decrease with the increase of the stress absorbing layer modulus,with the increase of the stress absorbing layer thickness,the stress at the bottom of the surface layer decreases,too.Secondly,the paper uses the software to set up three kinds of commonly used interlayer bonding measures in the model of recycled cement stabilized course pavement,through the analysis and calculation,the effect of three different layers of measures on delaying the reflection cracks were compared.Based on the internal stress of the three different absorbing layers,we analyzes the principle of different interlayer bonding to alleviate the delayed reflection crack.The results show that the geogrid,the rubber asphalt macadam layer and the SBS stress absorbing layer play an important role in reducing the stress concentration under the vehicle,followed by the rubber asphalt gravel layer,the worst is the geogrid.Thirdly,the indoor reflection crack simulation test of the recycled cement stabilized course pavement is designed to verify the calculated results.In order to better simulate the material characteristics of recycled cement stabilized course,we have improved the four-point bending fatigue test,The anti-cracking effect of three kinds of measures,SBS stress absorbing layer,geotextile and geogrid was evaluated by the fatigue life of the slit beam.The experimental results show that the fatigue life of the beams can be improved by the three measures under three kinds of strain which are 500??,1000?? and 1500??.The farigue life of SBS stress absorbing layer is longer than that of grid and geotextile.The simulation results and experiment show that the SBS stress absorbing layer is more effective than the grid.Finally,combined with the finite element analysis and economic research,according to the existing road design method,the paper puts forward the design control mode of crack under recycled cement stabilized course pavement.The road structure of recycled cement stabilized course pavement which is suitable for setting SBS stress absorbing layer is recommended.So this paper provides valuable guidance and reference for the practical application of recycled cement stabilized pavement.