Research Initiation: Determination of Microcracked Zone in Concrete by Laser Speckle Metrology

本研究的目的是用激光散斑计量学方法研究混凝土断裂过程区微裂缝的形成和范围。具体地说，这项研究将检测加工区内人口稠密的微裂缝区域，测量微裂缝宽度的增长率，描述试验中的宏观裂缝-微裂缝演化，并开发一个模型来评估混凝土中的裂缝扩展和断裂参数。这些研究将对波特兰水泥、砂浆和混凝土试件进行。将对双悬臂梁试件和等高线双悬臂梁试件进行检验。一系列试件将在两边都有凹槽进行测试。另外两个系列的试件将被测试：一个系列将只在一侧有凹槽，而另一个系列将完全没有凹槽。这三个主要系列包括不同的材料、样本类型和样本尺寸。

Objectives of this study are to investigate the formation and extent of microcracks in fracture process zone of concrete by laser speckle metrology. Specifically, the research will detect the densely populated microcracked region within the process zone, measure the rate of increase in microcrack width, describe the macrocrack-microcrack evolution from experiments, and develop a model to evaluate the crack growth and fracture parameters in concrete. These studies will be carried out for portland cement, mortar, and concrete specimens. Both double cantilever beam specimen and the contoured double cantilever beam specimen will be examined. A series of specimens will be tested with grooves on both sides. Two other series of specimens will be tested: one series will have grooves only on one side, and the other series will have no grooves at all. The three major series comprise different materials, specimen type, and specimen dimensions.