Study On The Structure And Material Of Asphalt Pavement On The Zones With The Feature Of Heavy Loads And High Temperature

Rutting is a unique damage phenomenon of asphalt pavement. It is a worldwide long-term puzzle for road workers both at home and abroad. According to statistics, more than 80 percent of the pavement maintenance associated with the rutting. The rutting problems are more prominent for the asphalt pavement on the zones with the heavy loads and high temperature. Therefore, it is of very important theoretical significance and practical value to study the structure and material of asphalt pavement on the zone with the heavy load and high temperature.Based on the field survey of asphalt pavement with the feature of heavy loads and high temperature, lots of laboratory tests and theoretical research, main achievements are concluded as follows:(1) Based on asphalt pavement investigation and the sampling specimen rutting test results of the typical heavy load and high temperature zone, the key internal reasons of impact on the rutting of asphalt pavement are studied by using analysis of variance, regression analysis, and correlation analysis. The empirical formula of the rutting depth related to the DS (dynamic stability) of each layer was first established:Accordingly, the asphalt mixture design control criterion of bottom layer of the asphalt pavement dynamic stability in the heavy load and high temperature zone is proposed. The DS criterion in the usual section is 800. In the long and large lognitudinal grade or super- transverse slope section criterion is proposed to increase to 1,000. It is proposed the asphalt concrete middle layer should use modified asphalt and its DS not less than 3,000.(2) Using the asphalt mixture special triaxial testing device, systematically study the impact of grade, aggregate, asphalt cement, volume of air voids and temperature on the asphalt mixture shear properties. The experiential model of the asphalt mixture shear parameters c,φand DS is firstly put forward:(3) Using DSR, IR, DSC and TG analysis means, the high-temperature properties and strengthen mechanism of asphalt mortar of modified asphalt PG76 and PG82 cellulose fiber and polymer fiber and AH-70 and modified asphalt PG76 with anti-rut agent are carried out preliminary study from the microscopic view. The optimal amount is proposed.(4) The high temperature properties of SMA-13 about PG76, PG82 and PG82 with different amounts of polymer fiber as well as AC-20 about PG76, AH-70 and AH-70 with different amounts of anti-rut agent are systematically comparatively analyzed. The test results show that SMA-13 with PG82 incorporate polymer fiber and AC-20 with AH-70 incorporate anti-rut agent have a noticeably improvement in the aspect of high temperature performance. Using the orthogonal analysis method, the high temperature properties of SMA-13 with fiber polymer and AC-20 with anti-rut agent by the impact of the mixing temperature, rolling temperature, dry mixing time and wet mix time is analyzed and proposed appropriate technical parameters.(5) Using 3D FEM, time-temperature equivalence principle, the maximum shear stress of the pavement each layer and its change law are analyzed under the different conditions of axle load, temperature, longitudinal slope, vehicle speed, supertransverseslope. It shows that overload axle and ultra-high temperature (speed) are the main factors affecting road shear stress. At the same time, the stress conditions of asphalt pavement structure under different factors coupling (condition) of the material combinations of the surface layer, temperature and load conditions are analyzed by using 3D FEM. Reference to shear strength checking methods of urban road asphalt pavement, the pavement structure shear properties on the different conditions were checked under the materials with measured parameters. Hereby, the recommended pavement structure adapting to different road conditions and the corresponding DS design criterion of asphalt mixture are suggested.(6) Combining with indoor tests and the results of the analysis about pavement structure, the reasonable pavement structure and materials composition of test road under the different conditions is designed and implemented. After more than one year tracking test the results shows that the test roads have an excellent service performances and the rutting is also in a good control. It indicates that the pavement structure and the materials design of the test roads are successful. Those valuable experiences are referred to similar highway asphalt pavement structure and materials design in the future.