Research On Anti-cracking Performance Of Laying Stress Absorbing Layer Asphalt Overlay Structure

Cement concrete pavement in the past always inevitably there are cracks and joints, reflective cracks will appear in the long-term effect of vehicle and temperature change, the original characteristics of the pavement is affected, pavement period will also be shorter than expected. A method of transformation at present the most commonly used measures and the effects are obvious, is the asphalt concrete surface layer covered on the cement concrete pavement of the original, such a construction method is not only simple, and the cost is low, the negative effect on the environment is small, while maximizing the use of existing pavement as roadbed.Stress-absorbing layer is a kind of special polymer modified asphalt mixture with good waterproof anti-permeability, which has particle size and high asphalt content; it is of good low-temperature toughness and high temperature stability, which can prevent stress concentration, and eliminate part of the shearing stress and tensile stress;it is of thickness effect of stress absorption and deviation effect which makes the reflection crack deviate from original cracks. Stress-absorbing layer itself is of certain thickness, and the tress-absorbing layer can reduce the thickness of additional asphalt structure. Main materials of stress absorbing layer are: SAMI, soft asphalt concrete,asphalt gravel, emulsifying asphalt processing aggregate, STRATA stress-absorbing system(highly elastic polymer cement material and mixture composed of aggregate with a maximum diameter of 9.5mm), and SAMPAVE stress absorbing layer. The setting of stress absorbing layer has a certain effect on reflective cracks mitigation. It is needed to take into consideration of road condition to prevent or reduce reflection cracks, find a reasonable anti-cracking measure to achieve the desired effect.This paper mainly studies the following contents:First of all, carry out load stress analysis. Take advantage of ABAQUS simulation as a tool to conduct analogue simulation. Under the condition of set traffic load, carry out deep study of the law that stress of the overlay structure, deflection, and deflection difference change with the changes of the thickness and modulus of asphalt, and thickness of the asphalt concrete overlay.Secondly, carry out the analysis of temperature stress. Take advantage of ABAQUS simulation as a tool to conduct analogue simulation. Under the condition of set temperature load, carry out deep study of the law that stress of the overlay structure,deflection, and deflection difference change with the changes of the thickness and modulus of asphalt, and thickness of the asphalt concrete overlay.Furthermore, carry out load-and-temperature coupling stress analysis. Take advantage of ABAQUS simulation as a tool to conduct analogue simulation. Under the condition of corresponding coupling effect, conduct study of coupling stress of stressabsorbing overlay structure. Make comparison between two common stress-absorbing layers of SAMI and modified emulsified asphalt fiber seal about the coupling stress.