The Research On Performance Evaluation Method And Application Of High Viscosity Modified Asphalt

Open-graded asphalt friction course(OGFC) has good function of sliding resistance, noise reduction and drainage. It is widely applied in our country in recent years. High viscosity modified asphalt as one of the core material of OGFC, its performance directly affects the quality of the pavement performance of OGFC. But so far, There is a lack of well suitable for performance evaluation method of high viscosity modified asphalt in the world, and the technical requirement for high viscosity modified asphalt is also not very clear. So this paper researched on the performance evaluation method of the high viscosity modified asphalt systematically.This paper took two kinds of high viscosity modified asphalts as the research objects, and selected 70 # matrix asphalt as the experiment contrast. Starting from studying several aspects of performance of high viscosity modified asphalt, such as high temperature performance, low temperature performance, therml performance and anti-aging performance, a variety of evaluation methods were used, and the applicability of these evaluation methods for the high viscosity modified asphalt were also analyzed in this paper.This paper evaluated the high temperature performance of high viscosity modified asphalt by using the penetration and penetration index, softening point and equivalent softening point, 60℃ dynamic viscosity, zero shear viscosity, carrying on dynamic shear rheological test amd multiple stress creep recovery test, and evaluated the low temperature performance by using the low-temperature penetration, ductility, equivalent brittle point and carrying on the bending beam creep test, using penetration index(PI), penetration-viscosity number(PVN), viscosity-temperature susceptibility(VTS) and viscosity-temperature curve to evaluate the thermal performance, carrying on the rotating thin film oven heating operational test, pressure aging vessel and atomic force microscope test to research the anti-aging performance.Through a series of research, it shows that those two kinds of high viscosity modified asphalts both have better rutting resistance at high temperature and crack resistance at low temperature than 70 # matrix asphalt. In the range of temperature studied in this paper, the high viscosity modified asphalt is less sensitive to the temperature. In addition, the high viscosity modified asphalt has better anti-aging properties and good rutting resistance at high temperature after aging, but the long-term aging will greatly deteriorate its crack resistance at low temperature.Through comparing and analyzing the various evaluation methods, it shows that multiple stress creep recovery test is a better evaluation method for the performance of high viscosity modified asphalt at high temperature compared with other evaluation methods, and bending beam creep recovery test is more suitable for evaluating its performance at low temperature than other method. Penetration index(PI) is suitable for evaluating the temperature sensitivity of high viscosity modified asphalt in low temperature range, while using the WLF equation regression viscosity-temperature curve can well evaluate the thermal performance of high viscosity modified asphalt in medium temperature range.The viscosity-temperature curves which were obtained by Brookfield viscosity test is suitable for evaluating the thermal performance of high viscosity modified asphalt in high temperature range. Atomic force microscope test can better reveal the aging process of asphalts based on the microscopic structure, and help us have a better understanding of the changes of macro road performance of high viscosity modified asphalt in the process of aging.