“…Presently, NDT used in civil engineering structures, are easier to handle due to the continuous development of measuring technology and, taking into account the “correct” evaluation of the results, provide a reasonable basis for a reliable assessment of the actual condition of the structure. There are various NDT techniques have been used for decades, currently more than 70 types of standardized testing methods can be applicable to the evaluation of concrete structures, e.g., acoustic emission [3,4,5,6], infrared thermography [7,8,9], ground-penetrating radar [10,11,12,13], Fiber Bragg grating (FBG) [14,15], or digital image correlation (DIC) [16,17,18].…”