| Top-down cracking is one of early diseases of asphalt pavement, which has a greatinfluence on the road performance and service life of the asphalt pavement. At present,cracking mechanism of Top-down cracking is studied only by the finite element methodanalysis in the domestic with the lack of the analysis of the analytical method. So it is verynecessary to study cracking mechanism of the Top-Down cracking with the analytical methodand to work out the judgment criteria this paperThis paper built a tire-ground model applicable to analyze top-down cracking of asphaltpavement with analytic method with reference to a large number of domestic and foreignliterature and research findings. The paper got the temperature field of pavement structurewith AI method and obtained the dynamic modulus of spring, summer, winter conditions frombefore-aging to after-aging according to asphalt aging prediction model in the case of aginglife, temperatures, depth and porosity. Based on layered elastic mechanics theory system andanalytical method, a mechanical calculation model was established, which is used for themechanical calculations of asphalt pavement structure under vehicle load and asphaltpavement temperature stress calculations sudden cooling after aging, and it also compiledcalculate program of analytical method with Matlab software. Then this article put forwardstress analysis method of top-down cracking. By analyzing the calculation results of betweenfinite element and analyticalcalculate method, the paper got their difference at about20%. Byanalyzing the research results of the test road and the calculation results of analytical method,this paper got the measured values and calculated values difference at about30%. Within theerror range at the same time, this paper further tested the feasibility of analytical calculatemethod. The paper used the analytical method calculation program to calculate the stress ofspring, summer and winter working conditions before aging and the stress with suddencooling after aging.Cracking mechanism of Top-Down cracking is that: When pavement is unaged, theanalysis shows that shear stress under wheel load is the major reason that caused top-downcracking. After aging, the tensile stress under wheel load is the major cause leading totop-down cracking. After aging and sudden cooling, the maximum tensile stress of wheel loadis greater than the tensile strength of material, which cause the pavement cracking. |
