沥青路面抗疲劳断裂半刚性基层强度标准研究

Study on Strength Standard of Semi-rigid Base Course for Fatigue Fracture Resistance of Asphalt Pavement

为确保水泥稳定碎石(CSG)基层在交通荷载反复作用的情况下不出现疲劳开裂,提出了基于结构与材料一体化控制的CSG材料强度标准的确定方法;研究了CSG基层的力学特性和疲劳特性,建立了力学强度增长模型、力学指标间的关系模型和疲劳方程;推荐了四川省典型沥青路面抗疲劳断裂的CSG基层强度标准。研究发现:CSG的各项强度指标都随养生龄期呈非线性增长,采用骨架密实结构有利于提高CSG的力学强度。提出的力学强度增长方程可以准确预估不同龄期CSG的力学强度;提出了控制疲劳开裂的CSG基层7天无侧限抗压强度标准与7天劈裂强度标准的确定方法,该方法能实现结构与材料一体化设计,可进一步提升CSG基层的疲劳寿命。

In order to ensure that the cement stabilized macadam(CSG)base does not appear fatigue cracking under repeated traffic load,the determination method of CSG material strength standard based on the integrated control of structure and material is proposed;the mechanical and fatigue characteristics of CSG base are studied,and the mechanical strength growth model,the relationship model between mechanical indexes and fatigue equation are established;the strength standard of CSG base course for fatigue fracture resistance of typical asphalt pavement in Sichuan province is recommended.The research finds that the strength index of CSG increases nonlinearly with curing age.The use of dense skeleton structure is beneficial to improve the mechanical strength of CSG.The mechanical strength growth equation can accurately predict the mechanical strength of CSG at different ages;the determination methods of 7 d unconfined compressive strength standard and 7 d splitting strength standard for controlling fatigue cracking of CSG are proposed,which can realize the integrated design of structure and material and further improve the fatigue life of CSG base.