基于细观力学性能的功能型沥青混合料研究

发布时间：2018-01-13 07:00

本文关键词：基于细观力学性能的功能型沥青混合料研究　出处：《华南理工大学》2014年博士论文　论文类型：学位论文

【摘要】：解决沥青路面早期“功能性”损坏问题的关键在于根据路面使用的功能需求，有针对性地进行功能型沥青混合料的设计。车辙作为当前沥青混凝土路面的主要病害之一，最常用的技术防治措施是使用改性沥青，但会造成工程造价的大大增加。骨架密实结构由于骨架的嵌挤作用使得其具有良好的抗车辙性能，在混合料级配设计中逐渐得到重视。但目前对于混合料内部骨架结构的认识有待深入研究，混合料是否真正形成了最优的骨架结构却很难判定，现有粗集料骨架状态的判据也显得过于笼统而简单，设计方法并不能有效保证设计的沥青混合料具有优良的主骨架结构。基于上述背景，，本文以数字图像处理技术和离散元方法为研究手段，以主骨架的构成及其细观接触特性研究为主线，从微（细）观角度对沥青混合料的内部结构进行系统研究，揭示主骨架的细观结构组成以及粗集料接触特性等本质属性和内在规律，在此基础上提出基于分级掺配法和细观评价指标相结合的骨架密实抗车辙功能型沥青混合料的设计方法；结合工程实际，将本文提出的设计方法应用于实践，通过铺设UM岩沥青改性沥青路面试验路进行跟踪观测，验证了设计理论和方法的可行性，并取得良好的经济效益。同时，为减少沥青混合料设计过程中的误差和工作量，探讨利用离散元方法进行级配设计的可视化设计方法。论文的主要工作和创新成果如下： 1.以数字图像处理技术和离散元方法为研究手段，对混合料内骨架、主骨架的构成和细观结构基本特性进行了系统研究，在此基础上考虑集料接触特性对VCAmix计算的数字图像法进行了优化，提出以平均配位数n c和“悬浮”粗集料含量C作为主骨架质量的细观定量评价指标。 2.提出基于分级掺配法和细观评价指标相结合的骨架密实功能型混合料设计方法，该设计方法可保证粗集料相互嵌挤形成最优主骨架，可靠度高且试验量小，设计的混合料具有良好的抗车辙性能。运用此方法设计功能型沥青混合料，经室内试验验证后应用于工程实践，通过铺设试验路并进行跟踪观测，验证了设计理论和方法的可行性。 3.对主骨架结构特性及其稳定性的微（细）观影响因素如不同沥青混合料粗集料接触特征、各档粗集料接触贡献率、配位数、粗集料倾角、接触链结构形态稳定性和主次接触链的特征等进行了统计和细观力学分析，提出设计优良主骨架结构并增强主骨架整体稳定性的优化措施和细观评价标准，以保证主骨架具备较强抵抗外部荷载的能力，提高沥青混合料的整体抗车辙性能。 4.利用离散元方法，对骨架密实功能型混合料设计过程中试验量和误差均较大的分级掺配过程进行了可视化设计的有益尝试，得到具有最优主骨架的混合料级配。该方法操作方便、数据离散性小，克服了传统试验误差较大和试验量大的不足，极大地提高了混合料设计的效率和经济性，具有重要的现实指导意义。 5.从对主骨架约束的角度分析了UM岩沥青掺量对基质沥青高温性能、低温性能和抗老化性等路用性能的影响，确立了UM岩沥青改性沥青的PG高温等级和低温等级，并对UM岩沥青改性混合料的路用性能进行了研究。以本文提出的设计方法设计骨架密实功能型混合料，通过掺入价格便宜的UM岩沥青以改善沥青胶浆的性能，加强对主骨架的约束来增强沥青混合料的抗车辙性能，试验路跟踪观测结果表明社会经济效益显著。
[Abstract]:The key to solve the problem of early " functional " damage of asphalt pavement is to design the functional asphalt mixture according to the functional requirements of pavement . The most common technical and control measures are to use modified asphalt . The most common technical and control measures are to use modified asphalt . Based on the above background , this paper studies the internal structure of asphalt mixture by means of digital image processing technique and discrete element method , and studies the internal structure of asphalt mixture from the viewpoint of micro ( thin ) view . 1 . Based on the digital image processing technique and the discrete element method , the paper systematically studies the structure of skeleton , main skeleton and the basic characteristics of meso - structure in the mixed material . Based on this , the digital image method for the calculation of VCAmix is optimized by considering the contact characteristics of aggregate , and the quantitative evaluation indexes with average coordination number n c and " suspended " coarse aggregate content C as main skeleton quality are put forward . 2 . The design method of skeleton dense functional type mixture based on hierarchical blending method and meso - view evaluation index is proposed . The design method can ensure that the coarse aggregate is mutually embedded and extruded to form the optimal main skeleton , the reliability is high , the test quantity is small , and the designed mixture has good anti - rut performance . The method is applied to engineering practice after indoor test verification , and the feasibility of the design theory and method is verified by laying the test road and carrying out tracking observation . 3 . The factors such as the contact characteristics of coarse aggregate of different asphalt mixtures , the contact contribution rate of coarse aggregate , the coordination number , the inclination of coarse aggregate , the structural stability of the contact chain structure and the characteristics of the main contact chain are analyzed . 4 . By using the discrete element method , the authors have made a useful attempt to visually design the grading mixing process with large test quantity and error during the design process of the skeleton dense function type mixture . The method has the advantages of convenient operation and small data discreteness , overcomes the defects of large traditional test error and large test amount , greatly improves the efficiency and economy of the mixed material design , and has important practical significance . 5 . Based on the analysis of the influence of UM rock asphalt content on the high temperature performance , low temperature performance and anti - aging property of the matrix asphalt from the perspective of the constraint of the main skeleton , the PG high temperature grade and the low temperature grade of the modified asphalt were studied .

【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：U414

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