集料岩性及微观特征对沥青混合料路用性能的影响研究

发布时间：2018-04-03 11:45

本文选题：集料　切入点：岩性　出处：《吉林大学》2014年硕士论文

【摘要】：材料的组成和结构决定材料的性能，特别是在沥青混合料中用量最大的集料，不仅对沥青混合料的性能影响重大，而且对工程造价的影响也极为关键。公路路面病害中很多损坏现象是与集料性能密切相关的，集料性能和质量不高，是沥青路面出现破坏现象（如车辙、松散剥落、裂缝等）的主要原因之一，因此，研究沥青混合料集料的性能特点是非常重要的。但是由于设备、理论和方法的欠缺，目前的研究多数停留在宏观指标（如压碎值、磨耗值、棱角性等）上，，对集料的岩性和微观特征领域没有深入涉及。通过控制目前提出的集料宏观技术指标，公路沥青路面依然存在各种破坏现象，因此目前集料的宏观技术指标并不完善，在研究更多的集料宏观技术指标的同时，应该将集料的微观特性重视起来。本文采用X射线衍射分析技术和扫描电镜（SEM）及能谱仪（EDS）分析技术对集料的岩性和微观特征开展研究，所选集料岩样均来自内蒙省道308线小河西至上都段一级公路项目底面层的3种主要集料，分别为构造角砾岩、石英钠长岩和玄武岩。本论文按照现有行业规范对集料的压碎值、洛杉矶磨耗值、砂当量、棱角性、与沥青粘附性等技术指标进行试验，得出所选的这3种集料的宏观技术指标性能。最后根据工程最佳配合比设计，分别对所选3种集料构成的沥青混合料的路用性能进行试验分析。本文采用的X射线衍射技术是利用X射线衍射仪对岩样进行试验，获取岩样中晶体的X射线衍射图谱，然后利用XRD数据处理软件来分析岩样的矿物组成及质量分数、结晶度和晶粒尺寸，通过与集料的宏观技术指标比对，探讨集料岩石中矿物成分、结构及构造与集料宏观路用指标之间的对应关系。扫描电镜（SEM）主要分析岩样的表面微观特征、粗糙度信息以及观察粘附性试验，然后用Matlab软件计算岩样粗糙度。本文首次在扫描电镜实验过程中，通过定量的方法对沥青与集料的粘附性等级进行评价。利用Matlab软件对扫描电镜下的灰度图片进行数字化转化，定量计算集料表面粗糙度。探讨集料微观特征与沥青混合料路用性能指标的对应关系。研究发现集料中长石的性质能反映岩石的压碎值，晶粒大小与磨耗值反相关，晶粒越大，磨耗值越小，集料越耐磨。通过对粗糙度的测定，可以评价出集料对沥青混合料的冻融劈裂抗水损害性能，即水稳定性。因此集料的表面粗糙度可以作为沥青混合料水稳定性的微观评价指标。
[Abstract]:The composition and structure of the material determine the performance of the material, especially the aggregate with the largest amount in the asphalt mixture, which not only has a great influence on the performance of the asphalt mixture, but also on the construction cost.Many damage phenomena in highway pavement diseases are closely related to the aggregate performance. The aggregate performance and quality are not high, which is one of the main causes of asphalt pavement damage (such as rutting, loose spalling, crack, etc.), therefore,It is very important to study the performance of asphalt mixture aggregate.However, due to the lack of equipment, theory and methods, most of the current studies remain on macro indicators (such as crushing value, wear value, angularity, etc.), and there is no in-depth study on lithology and microscopic characteristics of aggregates.By controlling the macro technical index of aggregate, there are still various kinds of damage phenomena in highway asphalt pavement. Therefore, the macro technical index of aggregate is not perfect at present, while studying more macro technical indexes of aggregate,The microscopic characteristics of aggregates should be taken seriously.In this paper, the lithology and microcosmic characteristics of aggregates are studied by means of X-ray diffraction analysis, scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS).The selected aggregate rock samples are all from three kinds of main aggregates in the bottom layer of the first class highway project of Xiaoxi Chaodu section along the 308 line of Inner Mongolia Provincial Road, which are structural breccia, quartz sodium feldspar and basalt, respectively.In this paper, according to the existing industry specifications, the aggregate crushing value, Los Angeles wear value, sand equivalent, angularity, adhesion to asphalt and other technical indicators are tested, and the macro technical performance of the three kinds of aggregate is obtained.Finally, according to the design of optimum mix ratio of engineering, the road performance of asphalt mixture composed of three kinds of aggregates is tested and analyzed separately.The X-ray diffraction technique used in this paper is to test rock samples by using X-ray diffractometer, to obtain X-ray diffraction patterns of crystals in rock samples, and then to analyze the mineral composition and mass fraction of rock samples by using XRD data processing software.By comparing the crystallinity and grain size with the macroscopical technical index of aggregate, the corresponding relationship between mineral composition, structure and structure of aggregate rock and macroscopical road index of aggregate is discussed.Scanning Electron Microscopy (SEM) is used to analyze the surface microcosmic characteristics, roughness information and adhesion test of rock samples. Then the roughness of rock samples is calculated by Matlab software.In this paper, the degree of adhesion between asphalt and aggregate is evaluated by quantitative method in the process of SEM experiment for the first time.The grayscale image of scanning electron microscope was digitally transformed by Matlab software, and the surface roughness of aggregate was calculated quantitatively.The relationship between the microscopic characteristics of aggregate and the road performance index of asphalt mixture is discussed.It is found that the properties of feldspar in aggregate can reflect the crushing value of rock, and the grain size is inversely related to the wear value. The larger the grain size is, the smaller the wear value is, and the more wear-resistant the aggregate is.By measuring the roughness, the water stability of asphalt mixture can be evaluated by the freezing and thawing cracking resistance of aggregate to asphalt mixture.Therefore, the surface roughness of aggregate can be used as a micro evaluation index of asphalt mixture water stability.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U414

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