Study of the fracture process using laser holographic interfermetry and image analysis

The fracture process on cement based materials was studied using various holographic interferometry methods. Several aspects of the fracture process were studied on plane mortar (cement, water and sand) and polypropylene fiber reinforced cement under different loading configurations. Sandwich holography was used to analyzed mortar specimens loaded in tension. The real time method was used to determine the load increments required for accurate and easy evaluation of displacements. A single sensitivity vector set-up was used for the evaluation of crack opening displacements and a multiple sensitivity vector set-up was used for the evaluation of full displacement fields. In both cases the holographic images were acquired by a digital image analysis system. First, the images were enhanced for better recognition of the fringe patterns by elimination of high frequency noise and contrast improvement. Then, the image analysis system was used for automatic fringe count.