Theoretical and experimental investigations on textile-reinforced concrete spalling behavior: Fid-Bau Portal

Theoretical and experimental investigations on textile-reinforced concrete spalling behavior

Reisgen, U. / Schoene, J. / Schleser, M. / Jerabek, J. / Keil, A.

The spalling effect occurring under tensile loading of penetrated multi-filament yarns and textile fabrics has been studied both experimentally and numerically. The systematic experimental study of the spalling effect has been performed with the goal to classify the damage mechanisms leading to the development of longitudinal cracks. The important goal was the design and identification of the test setup capable of rendering the longitudinal cracks under possibly uniform distribution of tensile stresses without any disturbing effect of the stress concentration near the clamping. The development of ring stresses in the vicinity of the debonding process zone has been reproduced using strength based bond law with a distinguished adhesive and cohesive part. The resulting stress state is comparable with idealization of the three dimensional stress state based on the mechanical bond with ribs. However, the role of the ribs is played here by the adhesive process zone in the front of the developing mode II debonding crack. In the presented simulation the anisotropic damage model applied for the concrete could reproduce the development of longitudinal crack. Thus, it can be regarded as feasible for detecting the combinations of component material parameters with a proneness to spalling. The model also motivated to the substantial change of the experimentals. The "concrete cube" test set-up, with highly simplified geometry and loading conditions was designed. The highspeed video records of perform experiments showed the sequence of failure for the described cubic specimen, nevertheless the process of longitudinal crack development could not be verified. The effect of spalling taking place after the failure of the glass roving could be monitored and its cause illuminated. The experimental set-up shall be modified to enable observations on the crack development.