摘要
运用有限元方法建立环氧沥青混合料细观结构模型,对其间接拉伸试验(IDT)进行数值模拟.首先借助图像处理技术得到由集料和沥青砂浆组成的环氧沥青混合料二相细观结构,并通过蠕变试验获取沥青砂浆常温下的黏弹性材料参数,最后结合有限元手段建立包含集料、砂浆等在内的混合料细观结构有限元模型.数值模拟结果表明,有限元计算的混合料劲度模量与实际IDT试验结果吻合较好,通过改变加载方向、加载速率等参数,发现对混合料细观结构的劲度模量以及局部点位应力均造成一定影响,分析主要原因可能是由沥青混合料的内部结构分布不均匀性以及沥青砂浆的黏弹性特点所造成.研究成果可为微观有限元方法进一步推广应用于不同条件下沥青混合料微观力学响应仿真提供理论依据.
A finite-element model of the thermosetting epoxy asphalt mixture（EAM） microstructure is developed to simulate the indirect tension test（IDT）.Image techniques are used to capture the EAM microstructure which is divided into two phases：aggregates and mastic.A viscoelastic constitutive relationship,which is obtained from the results of a creep test,is used to represent the mastic phase at intermittent temperatures.Model simulation results of the stiffness modulus in IDT compare favorably with experimental data.Different loading directions and velocities are employed in order to account for their influence on the modulus and the localized stress of the microstructure model.It is pointed out that the modulus is not consistent when the loading direction changes since the heterogeneous distribution of the mixture internal structure,and the loading velocity affects the localized stress as a result of the viscoelasticity of the mastic.The study results can provide a theoretical basis for the finite-element method,which can be extended to the numerical simulations of asphalt mixture micromechanical behavior.
基金
Program for New Century Excellent Talents in University(No. NCET-08-0118)
Specialized Research Fund for the Doctoral Program of Higher Education (No. 20090092110049)
