采用数字图像相关法进行收缩试验研究

半刚性基层材料已广泛应用于我国高等级公路路面结构中,但半刚性基层材料在温度作用或/和失水作用下产生的收缩应变一旦超过材料自身所能承受的极限拉应变，就会发生开裂，影响路面的使用性能。选择合适的收缩试验方法对半刚性基层材料的收缩性能进行研究非常具有现实意义。针对传统收缩变形测量方法的不足，采用数字图像相关方法对一种典型的半刚性基层材料进行室内收缩试验研究，分析其早期收缩应变的变化规律；对收缩变形前后的图像进行相关计算，获得全场的收缩变形，并与传统收缩试验结果相比，该方法所得结果可重复性好，稳定性好，精度更高。

Shrinkage experimental study using digital image correlation method

Semi-rigid base course materials are widely used in the high-class highways in China. If shrinkage strains of semi-rigid base course materials caused by the variations of temperature or/and moisture exceed the ultimate tensile strain that the material can bear, it will fracture, and the service performance of the pavement will be influenced. Choosing suitable shrinkage test method to study semi-rigid base course materials’ shrink performance has high practical significances. For the shortage of the conventional shrinkage measuring method, the lab shrinkage experiments on a kind of typical cement stabilized macadam are studied by the digital image correlation method(DICM), the early change laws of shrinkage strains are analyzed; by calculating correlation of the images captured before and after deformation, DICM is employed to obtain the whole-field shrinkage deformation. Comparing with the conventional shrinkage test results, the repeatability is fine, the stability is good and the accuracy is higher.