Asphalt Pavement Top-Down Cracking Influencing Factors And Evaluate Analytical Study

Top-down cracks is a sort of pavement failures, the major causes of leading top-down cracks are repeat traffic loads and low temperature stress. Top-down cracks having been considered as reflect cracks can result in asphalt pavement losting bearing capacity.Cracks is a matter of not only pavement structural design, more is materials designed matter.In order to avoiding cracking ,asphalt mixture demand greater tensile strength.This article aims at analyzing influence of crack resistance constructional materials of asphalt mixture.Mainly researchig influence of materials such as aspalt dosage,gradation,asphalt catalogue to top-down cracks formed and extended.Adopting AC-16 upper,middle,lower limit as test gradation ,Zhong hai 90# body asphalt,SBS modified asphalt,TPS modified asphalt as asphalt binder of mixture.This article introduce into dissipation creep strain energy limit(DCSEHMA),to analyze asphalt mixture cracking mechanism.This research based on asphalt mixture indirect tension test, DCSEHMA reflect properties of asphalt mixture,such as gradation,asphalt property,aggregate characteristics and so on. All kinds of asphalt mixtures are proceeded 25℃indirect tension test, ascertaining tensile strength and fracture energy density of different asphalt mixture.This article carried out resilient modulus of asphalt mixtures by indirect tension test at 25℃,to determine dynamic resilience modulus and DCSEHMA.Carrying out indirect tensile creep test at 25℃, to determine creep compliance,DCSEmin (asphalt mixture cracking requires minimum dissipation creep strain energy) and energy ratio ER= DCSEHMA /DCSEmin.ER is criteria to determine whether asphalt mixture can be crack and thichness of asphalt pavement. Finally,carrying out split fatigue test at 25℃for each asphalt mixture,to demonstrate whether DCSEHMA acting as asphalt mixture crack resistance indicator is validity .