Study On Fatigue Properties Of Warm-mixed Crumb Rubber Modified Asphalt Mixtures Under Aging

Road performance of asphalt mixture is reducing during service period due to the aging.Study on fatigue performance of asphalt mixture before and after aging is of great value for clear influence factors of fatigue performance and estimate fatigue life of asphalt pavement.Now,the large number of waste tires has caused"black pollution"to the environment.,rubber powder modified asphalt technology has been brought into existence.But because of the bigger viscosity of crumb rubber powder modified asphalt,which make a problems such as high construction temperature.The asphalt mixture warm-mix technology reduces the construction temperature and the environmental pollution while ensuring the road performance of asphalt mixture.Therefore,it is of great value to combine the crumb rubber powder modify technology with the technology of warm-mixing.In this paper,four kinds of rubber powder modified asphalt mixture?60 mesh HMA,60 mesh WMA,mix mesh HMA,mix mesh WMA?were studied with before and after the addition of arm-mixed agent?surfactant SDYK?,considering the hot oxygen aging effect,combine with the regional climate and load characteristics?temperature and strain level?designed four-point bending fatigue test,and uses the fatigue performance evaluation index studied the fatigue performance of warm-mix crumb rubber powder modified asphalt mixtures under the action of aging.Firstly,GRA method were used to study the five influence factors of asphalt mixtures?fatigue property.It is found that the experiment temperature has the greatest influence on the anti-fatigue performance of the asphalt mixture,load levels and aging degree follows,the influence of different powder sizes and warm-mixed agent is smaller.Then,the fatigue property and fatigue damage were studied by analyzing the index-S₀,N_f,W_f and fatigue damage factor D about the experimental data of asphalt mixtures before and after aging.It is found that the aging effect reduces the fatigue performance of four asphalt mixtures,and the worse the aging degree,the worse the anti-fatigue performance.And damage of asphalt mixture under fatigue load is characterized by:no matter before and after aging,damage is not very big between difference aging levels in the first stage,but in the second stages show that the more serious the aging,the faster the injury development,resulting in a decline in asphalt mixtures?fatigue resistance after aging.In addition,60 mesh powder asphalt mixture make asphalt mixtures obtain better anti-fatigue performance but weaker in anti-aging performance,while SDYK improving the fatigue resistance and anti-aging performance of asphalt mixtures.Finally,the traditional fatigue equation of four asphalt mixture before and after aging were established,then analysis the fatigue equations?parameters;It is found that with the increase of aging degree,the anti-fatigue property of asphalt mixture is worse,and the sensitivity to load change is increased,aging effect has a negative effect on the fatigue property of asphalt mixture.The addition of 60 mesh and SDYK make asphalt mixture have better anti-fatigue performance,and reduces the sensitivity of asphalt mixture to load change.