含基层缺陷沥青路面不同面层材料抗疲劳特性机理分析

目的为探讨面层沥青混合料在含有基层缺陷结构体系中的疲劳开裂演化机理,进行了抗疲劳特性的试验研究和理论分析.方法应用连续介质弹性疲劳损伤力学的基本原理,提出适合描述沥青混合料疲劳损伤开裂的演化方程,结合室内间接张拉疲劳试验,回归确定了疲劳损伤模型的计算参数,并采用有限元的计算方法,客观地评价了3种沥青混合料面层(AC20、SBR-AC20、RM-AC20)在含基层缺陷的路面结构中的抗疲劳特性.结果3种材料虽然呈现相同的疲劳损伤演化趋势,但由于各自材料抗疲劳特性参数的不同使其具有不同的抗疲劳特性,橡胶粉沥青混合料面层表现了最高的抗疲劳寿命.结论疲劳损伤力学的计算方法能够从机理揭示沥青路面结构的疲劳损伤演化的全过程,突破了以往传统疲劳强度理论和疲劳断裂力学相分离的状态;橡胶改性沥青混合料具有优良的抗疲劳特性加之具有节约能源的特点,值得推广使用.

Mechanism Analysis on Resisting Fatigue Performance of Different Wearing Course Materials of Asphalt Pavement Including Defect Base Course

Purpose in order to evaluate the fatigue performance of wearing courses composed of different mixtures overlaid on the defect base under traffic loading,the paper conducts the laboratory testing research and theory analysis.Method laboratory evaluation of fatigue performance of AC20,SBR-AC20 and RM-AC20 is focused on the indirect tensile fatigue testing.Based on the elastic fatigue damage mechanics,the suited evolvement function of fatigue cracking is present and relative parameters are regressed according to the results of indirect tensile fatigue testing.At the same time the finite element method is used to assess the fatigue performance of the three different kinds of asphalt mixtures.Result the same fatigue evolvement tendency of the three different kinds of asphalt mixtures is found,however,the different fatigue features are obvious owing to the different material parameters.The RM-AC20 exhibits the best fatigue performance among the studied three asphalt mixtures.Conclusion fatigue damage mechanics can reflect the whole course of fatigue cracking of wearing course and overcome the isolated state of conventional fatigue strength theory and fatigue fracture mechanics.RM-AC20 is worth being generalized owing to its superior anti-fatigue performance and profit of saving energy.