HMAC Performance Evaluation And Numerical Simulation For Special Section Pavement

The rutting of asphalt pavement is mainly caused by factors such as the increase of thetraffic volume, the aggravation of the axle load and traffic channeling, and is particularlyserious in long, steep slopes and turning sections. With excellent anti-rutting Performance,High Modulus Asphalt Concrete (HMAC) as a new kind of material is getting more and moreresearch and applications in recent years. Through a large number of tests, complicatedtheoretical analysis and structure calculation, the performance evaluation system of HMACand the application in special sections of highways was studied systematically, which providesthe theoretical basis and the technical supports for its application.In accordance with the anti-rutting performance of HMAC, HMAC-20and HMAC-25,two types of gradation were optimized. Combining the road performance of HMAC such asthe high-temperature, low-temperature and water stability performance, the gradation rangewas determined. HMAC-16, HMAC-20and HMAC-25, three types of gradation were choseand experimental study on compressive resilient modulus and dynamic modulus wereconducted under the temperature of15,20and60℃which proposed the evaluation index andtechnical requests of modulus. Based on the experimental results of high-temperatureperformance tests such as rutting test and uniaxial penetration test, water stabilityperformance tests such as residual stability test and freeze-thaw splitting test and thelow-temperature flexural test for low-temperature performance, the performance evaluationsystem for HMAC was established which is mainly based on the anti-rutting performance andtake into account of low-temperature and water stability performance.Select some typical road sections, take field investigation of rutting in asphalt pavementand analyze its causes. Based on the elastic layer system theory, the three-dimensional finiteelement model of HMAC was established. With the model, the mechanical response of thepavement structure under the impact of the vehicle load in special sections such as emergencyspeed straight flat slope, long, steep slopes and turning sections was calculated and the maincauses of rutting in special sections was analyzed. By analyzing the mechanical responsewhen high modular layer lied in different structure position，the proper layer of HMAC inspecial sections was determined. Through orthogonal designs, the mechanical response anddeformation characteristics of HMAC pavement in special sections corresponding to differentload, surface and base layer thickness and modulus were analyzed and the reasonablepavement structure of HMAC pavement in areas with high-temperature and heavy load was recommended. According to the uniaxial static creep test, the viscoelastic parameters of ACand HMAC were obtained. Based on the viscoelastic theory, the permanent deformationdiscipline of HMAC was simulated, and the permanent deformation prediction model forHMAC pavement at special section was regressed.