Testing of Compressive and Bending Strength of Concrete and Monitoring Acoustic Emission Parameters

The mechanism of compressive failure is still in progress to be clarified ; this has been tried with acquisition and analysis of acoustic emission parameters. The processing of the AE data is often not trivial and because of that, simple tests on the concrete samples were made. This paper deals with the relations between load and acoustic emission activities in concrete under different loading conditions. The compressive strength loading test was done with decreasing the friction between the specimen and the loading plates by means of rubber backing and by that decreasing the shear stresses. During testing, the acoustic emission activity was acquired. The three-point bending strength testing was also done. Cyclic loading was applied in both uniaxial compression strength testing and three-point bending strength testing in order to observe the Kaiser effect and Felicity ratio. Presented paper includes the differences in reading the acoustic emission signal and its behavior during the loading, just before the fracture and at the very time the concrete is fractured.