沥青路面材料多尺度域力学行为及统一模型

发布时间：2018-04-14 08:17

  本文选题：沥青路面 + 多尺度　； 参考：《哈尔滨工业大学》2017年博士论文

【摘要】：沥青混合料材料组成的复杂形貌及空间随机分布导致其多尺度特性不可忽视。沥青混合料的宏观力学行为及损伤演变规律与其微、细观结构特性有着内在的关联性。为了解决具体工程的应用问题,宏观尺度上沥青混合料的统计平均性质是沥青路面材料优选的主要指导方针。基于层状弹性理论的沥青路面结构设计方法满足连续介质力学理论所提出的材料均匀化假设。单一尺度下小尺寸构件力学性能评价及基于连续介质框架的理论计算分析无法从多尺度本质上解释沥青路面材料与结构的力学行为及损伤机制。因此,开展沥青路面材料多尺度域力学行为及各尺度间相互作用的研究,有助于深入理解、分析及预估沥青混合料的力学性能。进而,从多尺度角度出发为沥青路面材料优化设计提供理论支撑及数据支持,为揭示沥青路面材料的损伤机理奠定基础。为探究集料-沥青界面微观交互作用的影响规律,借助扫描电镜与原子力显微镜,分析了集料表面及集料-沥青界面区的微观形貌差异;在集料矿物成分已探测的前提下,对比了沥青在石灰岩及玄武岩表面的高温润湿状况,基于原子力显微镜分析了常温条件下集料-沥青界面区的力曲线评价指标分布规律;基于自行开发的集料平行板,完成了集料粘附条件下的沥青动态剪切流变试验及直接拉伸试验分析。结果表明:集料表面微观形貌差异决定了沥青的微观裹附效果;集料-沥青-集料夹层的剪切与拉伸特性受集料类型的影响显著,其流变特性及抗拉伸破坏能力对石灰岩与玄武岩表现出明显的选择性;集料-沥青界面区交互作用具有温度/频率、夹层厚度及加载模式依赖性,且存在一个界面区临界厚度;从界面微观交互作用角度出发,集料平行板改进试验装置及测试方法适用于路用集料类型优选。界面区研究成果用于多尺度统一模型中界面区黏弹参数的求取。为定量评价沥青砂浆黏弹与低温特性,开发了小尺寸沥青砂浆无损成型装置,提出了其动态剪切流变参数测试方法;开展了沥青砂浆频率扫描、应力松弛、应力疲劳及静态蠕变试验分析,验证了该试验装置测试结果的复现性;完成了低温条件下沥青砂浆弯曲梁流变试验分析,分析了冻融循环及自然环境老化对沥青砂浆低温弯曲蠕变特性的影响。结果表明:沥青砂浆的体积指标与其材料组成关系密切,当沥青砂浆的有效沥青含量低于临界值时,其空隙率的增幅十分明显;沥青砂浆剪切特性与其级配、沥青含量及空隙率的联系紧密;最佳沥青含量及最优击实功是沥青砂浆低温弯曲蠕变性能的保障;空隙结构特征是沥青砂浆与沥青混合料冻融损伤机理差异的主导因素,高沥青含量沥青砂浆体现出冻融损伤及物理硬化双向竞争机制;合理的压实功可降低沥青砂浆因自然环境老化导致的低温开裂风险,早期老化主要体现在沥青砂浆中;所提出的沥青砂浆动态剪切流变试验与弯曲梁流变试验满足测试精度及性能评估的要求。沥青砂浆研究成果用于多尺度统一模型中沥青砂浆黏弹及损伤参数的求取。为系统描述沥青混合料细观结构参数分布规律,采用分形维数、形状指标、棱角性指标及傅里叶级数分析了细观尺度下粗集料轮廓的起伏程度;确定了沥青砂浆及沥青混合料间的临界空隙尺寸,实现了空隙轮廓分形维数的计算及其细观结构的表征;以骨架间隙率、质心三维分布、骨架三维分布为指标,评价了沥青混合料的骨架结构分布特性;提出了影响沥青混合料高、低温路用性能的细观结构特征参数。结果表明:粗集料长轴、中轴及短轴端部轮廓的起伏程度最高,细观尺度下粗集料表面形貌变化复杂;临界空隙尺寸之上的空隙视为初始缺陷引入到沥青混合料的材料组成中;沥青混合料空隙分布体现出一定程度上的横观各向同性规律;验证了骨架结构评价指标间的相互佐证关系,SMA类沥青混合料骨架结构分布最为紧密;骨架结构是影响高温稳定性的特征参数,空隙结构是影响低温抗裂性的特征参数,空隙分布是影响低温拉伸应变场分布的特征参数。细观结构研究成果用于多尺度统一模型中细观结构参数的描述。为创建沥青路面材料虚拟化试验设计平台,考虑界面区、初始空隙缺陷及材料损伤的影响,完成了沥青混合料细观单元等效模型的材料参数等效;开展了引入微观应变梯度及实测材料参数的细观单元等效模型力学行为分析;在Perzyna黏弹塑性本构模型的基础上,进行了考虑各向异性的多尺度统一模型力学行为分析。结果表明:在不影响计算精度的前提下,微观应变梯度的引入提高了计算效率;微观应变梯度的引入及实测材料参数的输入是细观单元等效模型通过验证的关键因素;多尺度统一模型与细观单元等效模型间力学行为存在着显著的正相关性;SMA类沥青混合料的计算力学行为表现最佳,与其组成材料性能及细观结构分布规律关系密切;由微观应变梯度、细观单元等效模型及多尺度统一模型间的相互传递关系,初步探究了沥青路面材料的尺度跨越机制。
[Abstract]:Asphalt mixture material with complex morphology and spatial random distribution of the multi-scale characteristic can not be ignored. The macro mechanical behavior of asphalt mixture and the damage evolution and its micro, meso structure characteristics have an inherent relevance. In order to solve the application problems of specific engineering, macro scale statistical average properties of asphalt mixture is the main guideline of asphalt pavement material selection. The design method of asphalt pavement structure layered elastic theory of homogenization is assumed to satisfy the proposed continuum mechanics theory based on the material. The small size component force single scale performance evaluation and analysis to explain the mechanical behavior and damage mechanism of asphalt pavement materials and structures from the multi-scale nature of calculation based on the theory of continuum framework. Therefore, study on the interaction of asphalt pavement materials and the mechanical behavior of multi scale domain among various scales That is helpful for understanding, analysis and prediction of mechanical properties of asphalt mixture. Then, from the perspective of multi scale to provide theoretical support and data support for asphalt pavement material design and optimization, lay the foundation for the damage mechanism of asphalt pavement materials. To explore the influence of micro - asphalt material set interface interaction, with the help of scanning electron microscopy and atomic force microscopy, analysis of the aggregate surface and microstructure of asphalt material in different interfacial zone; in the premise of aggregate mineral composition has been detected, compared to the high temperature asphalt in limestone and basalt run surface wet conditions, the atomic force microscope is analyzed based on material interface in normal temperature asphalt the stress distribution curve evaluation index; self-developed aggregate parallel plate based on the analysis of asphalt tensile dynamic shear test and direct test of material adhesion conditions. The results show that Set: the morphology of material surface difference determines of micro effect wrapped asphalt aggregate type; affected by shear and tensile properties of material of asphalt aggregate sandwich set significantly, its rheological properties and anti tensile ability of limestone and Xuan Wuyan showed obvious selectivity; aggregate asphalt interfacial interaction with temperature / frequency, interlayer thickness and loading mode dependency, and there exists a critical thickness of interfacial zone; starting from the micro perspective of the interaction between the interface, aggregate improved parallel plate test device and test method for pavement aggregate type selection. Interface research results obtained for the interface of multi-scale unified model in clay elastic parameters. For quantitative evaluation of asphalt mortar viscoelastic and low temperature characteristics, the development of small size asphalt mortar nondestructive forming device, the dynamic shear rheological parameter test method of asphalt mortar; carry out frequency sweep Description, stress relaxation, stress analysis and fatigue and static creep test, to verify the reproducibility of test results of the experimental device; analysis of beam bending creep test under the condition of low temperature asphalt mortar was completed, analysis of freeze-thaw cycle and natural aging effect on the bending creep properties of asphalt mortar at low temperature. The results show that the volume index of asphalt the mortar material composition closely, when the effective asphalt content of asphalt mortar is lower than the critical value, the porosity increase is very obvious; the shear properties of asphalt mortar and gradation, asphalt content and porosity of the closely related; optimum asphalt content and optimal compaction is bending creep performance of asphalt mortar security clearance; the structure is characterized in asphalt mortar and asphalt mixture freezing thawing damage mechanism of different dominant factors, high asphalt content of asphalt mortar reflects the freeze-thaw damage and hardening of two-way physical competition The mechanism of compaction; reasonable can reduce the asphalt mortar due to low temperature cracking risk of natural environment caused by aging, early aging is mainly reflected in the asphalt mortar and asphalt mortar; dynamic shear rheological test and bending beam rheometer test proposed meet the test precision and performance evaluation of asphalt mortar. Research results obtained for multi-scale unified asphalt in the model of mortar viscoelastic and damage parameters. For system description of asphalt mixture microstructure parameters distribution, the fractal dimension, shape index, angularity index and Fu Liye series analysis of meso scale fluctuation degree of coarse aggregate profile; determine the critical void size of asphalt mortar and asphalt mixture between. The calculation of void fractal dimension and its meso structure characterization; the skeleton clearance rate, three-dimensional distribution centroid, three-dimensional distribution framework as the index, the evaluation of asphalt concrete The distribution characteristics of material and structure; the influence of asphalt mixture, the meso structure parameters for low temperature performance road. The results show that the coarse aggregate long axis and short axis end profile of the ups and downs of the highest level of the meso scale coarse aggregate surface morphology is complex; the critical void void size. As the initial defects are introduced to the asphalt mixture composition; asphalt mixture void distribution reflects the transversely isotropic law to a certain extent; to verify the relationship and mutual support of skeleton structure indicators, SMA skeleton structure of asphalt mixture distribution most closely; skeleton structure is characteristic parameters that influence the stability at high temperature the space structure is the characteristic parameters of low temperature crack resistance, void distribution is the characteristic parameters of low temperature tensile strain field distribution. The meso structure research for multi-scale unified model in fine The concept of structure parameters. In order to create a virtual experimental design of asphalt pavement material platform, considering the interfacial area, effect of initial void defects and material damage, the material parameters of meso element equivalent model of equivalent asphalt mixture; carry out the introduction of micro strain gradient and the measured material parameters of meso element equivalent model of mechanical behavior analysis based on Perzyna; visco elastoplastic constitutive model, analyzed the anisotropic multi-scale unified model considering mechanical behavior. The results show that the computational accuracy is not under the influence of the micro strain gradient is introduced to improve the computational efficiency; micro strain gradient is introduced and the measured material parameters of the input is fine the concept of equivalent unit model through key factor verification; multi-scale unified model and micromechanical behavior of unit equivalent model exist significant positive correlation; SMA asphalt mixture The best performance calculation of the mechanical behavior of materials, with the composition of the material properties and the relationship between the distribution of meso structure closely; from the micro strain gradient, micro mutual transfer between unit equivalent model and multi-scale unified model between the initial exploration of the asphalt pavement material scale across the system.

【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：U414
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本文编号：1748438