基于细观结构的沥青混凝土宏细观参数相关性研究

发布时间：2018-12-17 02:10

【摘要】：沥青混凝土具有复杂的力学和热学特性,因此很难用宏观参数对其进行量化评价,当前出现用细观结构来预估沥青混凝土的宏观材料特性。为了研究细观结构和材料参数对沥青混凝土宏观力学和热学特性的影响,本文提出一种三维正方体集料投放算法,在考虑真实集料体积分布规律的基础上,给出一种包含正方体集料、沥青砂浆、界面和孔隙的四相体三维细观数值建模方法。反算获得细观材料参数,代入数值模型中进行仿真分析,从而预估沥青混凝土宏观力学和热学特性。首先,依据圆形和方形集料投放算法成型不同级配的二维数值模型,代入沥青砂浆和集料参数进行分析计算,研究集料形状、级配和空间位置对二维数值模型顶面压缩变形的影响。其次,在三维集料投放算法的基础上提出一种改进的四相体三维数值建模方法。通过对真实试件切面中的集料横截面进行面积识别分档统计其个数,将识别结果与不同数值模型切面的识别结果进行对比,验证瓦拉文公式的适用范围及三维数值建模方法的合理性。为了验证基于细观结构和材料参数预估沥青混凝土宏观力学和热学特性的合理性,分别建立考虑真实集料体积分布的三维数值模型,代入各相材料参数进行分析计算。最后,分别用松弛试验和热学试验结果对力学和热学仿真结果进行验证。结果表明本文提出的考虑真实集料体积分布的数值建模方法具有合理性,用细观结构和材料参数可以有效预估沥青混凝土的宏观力学和热学特性。
[Abstract]:Asphalt concrete has complex mechanical and thermal properties, so it is difficult to evaluate it quantitatively by macroscopical parameters. At present, meso-structure is used to predict the macroscopic material characteristics of asphalt concrete. In order to study the effect of meso-structure and material parameters on the macroscopic mechanical and thermal properties of asphalt concrete, a three-dimensional cube aggregate placement algorithm is proposed in this paper, on the basis of considering the law of volume distribution of real aggregate. In this paper, a three-dimensional meso-numerical modeling method of four-phase body including cube aggregate, bituminous mortar, interface and pore is presented. The mesoscopic material parameters are obtained by inverse calculation, and the simulation analysis is carried out in the numerical model to predict the macroscopic mechanical and thermal properties of asphalt concrete. Firstly, according to the circular and square aggregate dropping algorithm, the two-dimensional numerical model with different gradation is formed, and the parameters of asphalt mortar and aggregate are added to analyze and calculate, and the shape of aggregate is studied. The effects of gradation and spatial position on the top compression deformation of the two-dimensional numerical model. Secondly, an improved three-dimensional numerical modeling method for four-phase bodies is proposed based on the three dimensional aggregate placement algorithm. By counting the number of aggregate cross-section in the real sample, the recognition results are compared with those of different numerical models. The applicability of the Varavan formula and the rationality of the three-dimensional numerical modeling method are verified. In order to verify the rationality of predicting the macroscopic mechanical and thermal properties of asphalt concrete based on meso-structure and material parameters, a three-dimensional numerical model considering the volume distribution of real aggregate is established, and the parameters of each phase are analyzed and calculated. Finally, the mechanical and thermal simulation results are verified by relaxation test and thermal test respectively. The results show that the numerical modeling method considering the volume distribution of real aggregate is reasonable, and the macroscopic mechanical and thermal properties of asphalt concrete can be effectively predicted by using the mesoscopic structure and material parameters.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U414

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