• Iliopoulos, Sokratis
• Aggelis, Dimitrios G.
• Tysmans, Tine
• Sutter, Sven De
• Verbruggen, Svetlana

Abstract

Innovative composite materials in construction gain more applicability aiming at sustainability and lightweight design. Their mechanical and fracture behaviour is not always easy to predict due their inherent heterogeneity. In the present study hybrid beams made of Textile Reinforced Cement (TRC) hollow boxes with Carbon Fibre Reinforced Polymer (CFRP) bonded on concrete beams are subjected in bending. Their fracture behaviour is complicated as they may suffer from all the following mechanisms: cracking of the cementitious matrix, delaminations between the successive layer of TRC, debonding of the CFRP and concrete from the TRC box. Their mechanical performance is evaluated in relation to their design and composition and their fracture behaviour is closely monitored by Acoustic Emission (AE) and Digital Image Correlation (DIC). AE provides crucial information on the load of initial micro-cracking and DIC on the level of strain even before damage starts to develop. Furthermore, AE indices show good correspondence to the fracture mode and shift according to the imposed loading level. Beams suffering from a single major mechanism (cracking) exhibit nearly constant AE characteristics throughout loading, while beams suffering from delaminations exhibit longer AE waveforms of lower frequency compared to the pure matrix cracking. The tendencies are obvious from the initial part of the test, enabling predictions as to how the beams will eventually fail. Additionally, the use of DIC enables to relate AE, not only to the final damage pattern but to the strain field that is developing due to the external loading.

Topics

• impedance spectroscopy
• polymer
• Carbon
• composite
• cement
• acoustic emission