Performance Evaluation And Crack Propagation Studying Of Large-stone Asphalt Mixture

Due to historical reasons,China’s highways are mostly semi-rigid base pavement. Along with our country highway into the maintenance period of large-scale, how to delay and prevent the expansion of reflection cracks in the new pavement with semi-rigid base or pavement overlayer,is the urgent need to solve the problem. At present, some provinces in our country has a large stone asphalt mixture used in highway reconstruction and pavement overhaul project,but the material and structural properties have not been studied with meticulous.It is very important thorough more comprehensive and further study on material and structure of large size asphalt mixture, especially on the crack resistance of there search, to solve the crack sproblem of semi-rigid base asphalt pavement and pavement layer,and improve the service level of the highway and improve highway overhaul program design.It is also has very important practical significance.This study the anti-cracking performance of large stone asphalt mixture as the core, mainly has conducted the research in the following aspects:Introduces the mechanism of the rubber asphalt; Come to the law of preparation method and rubber powder dosage on the performance of asphalt rubber.Introduces the experimental method of Overlaytester for testing anti-cracking performan-ce of asphalt mixture from laboratory experiments and data processing.Through the "Dynamic Modulus Test" and "Hamburg wheel tracking test" and "Overlay Tester" and other comparative studies the dynamic mechanical properties at high-temperature and Anti cracking performance of large-stone porous asphalt mixture have been evaluated. That suggests the large stone asphalt with rubber asphalt as a cementing material holds the best pavement performance.Simulate the ability to delay the Expansion of reflection cracks of large stone asphalt using finite element method. The results show that the rubber large stone asphalt can indeed delaying reflection cracking.Combined with the Beijing to Taipei Expressway He-Xu south section project entity, this article compared the effect of different restoration measures, the results show that, the deflection of asphalt mixture with the asphalt rubber particle as the pavement base restoration measures is smaller,the number of anti-reflective crack is less, and the service life of pavement structure is longer.