Non destructive testing of reinforced concrete beams using acoustic emission


5th National Conference on NDT of the Hellenic Society of NDT (HSNT), 18-19 November 2005, National Technical University of Athens.

Athanasios Anastasopoulos, Apostolos Tsimogiannis, Timotheos Toutountzakis, Ek. Papanikolaou, A. Triantafyllou


Acoustic Emission (AE), Non-Destructive Testing (NDT) was applied during four-point bending tests of medium-scale reinforced concrete beams, deficient in shear. In total four specimens were tested: one beam without strengthening was used as a control specimen and the remaining three were reinforced in the shear spans with closed jackets made of continuous fiber (carbon) textiles (meshes) in combination with either an organic bonding agent (epoxy resin) or an inorganic one (cement-based mortar). Two different jacket designs were used following “conventional” and helical wrapping schemes. The efficiency of all strengthening systems was evaluated by means of Acoustic Emission.

The aim of NDT was the real time monitoring of AE activity versus the applied load, the qualitative damage characterization and the comparative evaluation of the different strengthening schemes applied. Qualitative evaluation was employed by means of AE energy rate per channels as revealed from zonal location. Further quantitative evaluation and 3-D location techniques were employed in order to accurately locate AE sources and to monitor their growth versus time and applied load. Real time evaluation enabled the identification of failure areas and the forecast of crack locations well before cracks were visible with naked eye. Furthermore, the results of post processing evaluation allowed for the verification of the witnessed failure mode (shear vs. flexural) and the assessment of the jackets’ relative effectiveness for shear strengthening.