Digital Image Correlation Pattern for Concrete Characteristics—Optimal Speckle

Digital Image Correlation (DIC) is an innovative effective method for assessment of stress-strain state of the structural element. The Digital Image Correlation technique enables to study cracking and fracture mechanisms in constructions, in order to obtain the full field of deformations and stresses and to evaluate the load-bearing capacity, reliability and residual resource. Measurement of deformations according to the DIC method is performed with the use of a stochastic contrast speckle pattern, which has to be previously applied to the studied surface. Good pattern determines high confidence of experimental results and low noise level and has to meet the following requirements: high contrast, the consistent speckle sizes and degree of filling of the surface, isotropy and randomness. This paper presents results of experimental research of prism concrete samples with different parameters of speckle pattern. The comparative analysis of experimental results enabled to determine the most optimal speckle sizes, pattern randomness and coverage.