The Research On Influence Factors To Performance Of Asphalt Based On Different Aging Methods

During the construction of asphalt pavement and its service stage,the performance of asphalt was seriously deteriorated with time until the asphalt pavement could not meet its service requirements any more,due to the influence of traffic load and environmental factors.The aging of asphalt was the source of its deteriorated performance,while the main cause of asphalt aging was the natural environment.In this paper,a research on asphalt aging in the conditions of heat,oxygen,and light was carried out,by simulating the aging environment for asphalt in an environmental chamber.In order to understand the actual environment of the road,in this paper,with meteorological parameters and internal temperature of pavement in Wenzhou area monitored and historical meteorological data consulted at first,a prediction model of internal temperature of pavement and an annual distributed regularity of ultraviolet radiation were obtained,based on which temperature parameters and UV parameters for indoor simulated test of asphalt aging were calculated and an experimental scheme was made:after a short term aging,asphalt was then aged respectively in the simulated experiments of oxygen-insulated aging,thermal oxidative aging and aging under coupling conditions of heat,oxygen and light based on temperature parameters and UV parameters.Then,the performance of asphalt with different aging situations was tested so as to further evaluate and analyze the characteristics of asphalt after aging.By testing penetration,ductility,softening point and dynamic viscosity at 60?before and after asphalt aging in different aging methods,component change and infrared spectrum of each stage,the influences of different aging methods on each performance index were analyzed,the result of which showed that the more influencing factors were involved,the more serious the aging was.With the contribution rates regarded as evaluating indexes on the basis of testing performance indexes,the resultshowed how contribution rate of temperature and coupling factors of heat and oxygen changed with the ultraviolet radiation intensity in the process of aging under coupling conditions of heat,oxygen and light;in addition,an analysis was made on how contribution rate of temperature and coupling factors of heat and oxygen on three major indexes and dynamic viscosity changed with time in the stage of thermal oxidative aging and aging under coupling conditions of heat,oxygen and light,so it was clear that the change rule ofcontribution rate of temperature on aging was contrary to the change rule of contribution rate of coupling factors of heat and oxygen on aging;for specific performance,at the same time when the aging time or total amount,the contribution rate of temperature decreases with the increase of the intensity of ultraviolet,and the same conditions,hot-oxygen factor contribution rate changes in contrast;in addition,in hot oxygen aging or hot oxygen aging optical coupling,the contribution rate of temperature on the three major indexes rose with aging time extended,the contribution rate of dynamic viscosity with the extension of aging time is reduced,and heat-oxygen factor contribution rate changes in contrast.By analyzing the average contribution rate of temperature,coupling factors of heat and oxygen and ultraviolet radiation,the result showed that,during thermal oxidative aging,heat alone contributed little to the aging of asphalt,that heat and oxygen coupling was the main cause of asphalt aging,and that the preliminary stage of aging under coupling conditions of heat,oxygen and light was based on aging under coupling conditions of heat and oxygen while the later period of it was light-aging-based.