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.
