This thesis focuses on the use of the acoustic technique (AT) on reinforced and plain concrete specimens. The aim of my research was to gain experience in early detection of crack formation on concrete structures. In the experiments, plain and reinforced beams were bended up to the failure and pull-out tests were carried out. Ribbed and plain reinforcements were used for the simulation of new and old concrete structures. The results of the aforementioned studies indicate that cracks and their locations can be detected much earlier by AT than by visual inspection. Through the experiments, the Kaiser effect was observed as well. All the experiments were performed in ZAG – Slovene National Building and Civil Engineering Institute, Ljubljana
