Determination of cracks due to load within reinforced concrete beams by acoustic emission method

In this thesis, shear and flexural deficient reinforced concrete beams were strengthened by Carbon Fiber Reinforced Polymer (CFRP) strips and the effects of strengthening on behavior and capacity of the beams were investigated under three point bending test. Acoustic Emission (AE) method was applied simultaneously to determine cracks, crack evolution, size, types, evolution times, locations, etc. Five reinforced concrete beams with dimension of 150 x 250 x 2300 mm beam were cast within the scope of the study. Among the test specimens, Specimen-1 and 2 were designed to be shear deficient. Specimen-2, was strengthened with U-shaped CFRP strips while reference specimen Specimen-1 was not strengthened. Specimen-3 was both shear and flexural deficient. It was strengthened with U-shaped CFRP strips. Specimen-4 and 5 were designed to be flexural deficient. Specimen-4 was not strengthened and Specimen-5 was strengthened with CFRP strips at its flexural region. Mechanical results and AE data obtained were evaluated and compared to reveal the fracture mechanisms and failure reasons of the test specimens. Keywords: Acoustic Emission, Strengthening with CFRP, Fracture Mechanism, Reinforced Concrete Beam