沥青结构层芯样分层变形的数字图像测量方法

Digital Image Processing Technique for Measurement of Coursed Deformation of Asphalt Pavement Core Samples

为有效评价芯样的分层变形和力学特性,将计算机图像识别应用于常规的沥青混合料单轴压缩蠕变试验,实现了沥青结构层钻芯取样分层变形的非接触测量和变形过程的拍摄、自动测量和自动记录,为沥青混合料蠕变试验提供了一种简洁、有效的测量手段。文中分析了测量精度和测量误差,讨论了端部约束对芯样不均匀变形的影响,给出了芯样采用常规测量方法和数字图像测量结果的比较。3层芯样单轴压缩蠕变试验中,以中面层的变形最大;加载历史的不同会导致材料细观结构的改变并引起力学性能的变化,高度压密芯样与路肩处芯样的变形规律不同,尤其在蠕变破坏阶段。

In order to evaluate the coursed deformation and mechanical property of core samples, a digital image processing technique is used for conventional uniaxial compression creep test of asphalt mixtures.Non-connect measuring process for measuring the coursed deformation of asphalt pavement core samples is realized. The shape and the deformation of the samples are automatically determined and recorded in real-time. This technique can be efficiently and conveniently applied to traditional creep tests apparatus. Accuracy and error of the measurement is analyzed, the effect of end restraint on the non-uniform deformation of samples is discussed, and measured results of core samples deformation are given for comparison between traditional method and the presented technique.In the uniaxial compression creep test of the cores, it is observed that the deformation of asphalt middle course is the maximum. The different loading history of cores results in the changes of material meso-structure and mechanical property. The deformation law of the highly compacted cores is different from the cores in shoulder, especially in creep failure step.