Bong-Gu Kang

Numerical and experimental evaluation of damage parameters for textile reinforced concrete under cyclic loading

The textile reinforced concrete (TRC) has emerged in the last decade as a new composite material combining the textile reinforcement with cementitious matrix. Its appealing feature is the possibility to produce filigree high-performance structural elements that are not prone to corrosion as it is the case for steel reinforced concrete. In comparison with other composite materials, textile reinforced concrete exhibits a high degree of heterogeneity and imperfection that requires special treatment in the development of numerical models.

Damage Behavior of Yarn Embedded in Concrete Using Acoustic Emission Analysis

To analyze the damage and failure mechanisms of a multifilament yarn embedded in concrete during a pullout test, an acoustic emission analysis was carried out for the identification and localization of filament ruptures. The different damage mechanisms (filament rupture, filament debonding, and concrete microcracking) causing acoustic emission were first characterized for separation. Tests were carried out to generate isolated signals, which were studied using signal and frequency analysis. A high localization accuracy of the filament ruptures in the yarn pullout test could be achieved, and the damage progress of the yarn during the pullout test could be analyzed in detail.

Application of Fracture Mechanics on Unreinforced Concrete Walls

In this contribution investigations on the size effect of unreinforced concrete walls which are funded by the Deutsche Forschungsgemeinschaft (German Research Foundation) are described. Inducement of this project was the subordinated meaning of unreinforced concrete walls for residential buildings caused by not available design models, although these walls have build-practically and economically substantial advantages. The major reason for the absence of relations according to plain concrete, which could be consulted for design, are the missing experimental investigations on the load configuration of vertical force and bending acting together.

Analysis of Textile Reinforced Concrete at the Micro-level

To increase knowledge on the load carrying behaviour of textile reinforced concrete (TRC), simulations are important to complement experimental investigations. Due to the heterogeneous structure of TRC, different damage mechanisms at different scales are found. Since not all details can be represented in one model, different modelling levels have to be considered. This paper focuses on the modelling of TRC at the micro-scale and therefore particularly at the experimental and theoretical determination of the material, bond and micro-structural properties needed for the modelling. The consideration of fatigue damage due to cyclic and sustained loading, which is indispensable for the design of structural members, enhances the complexity of the material and bond laws. To verify the developed model, yarn pullout tests under monotonically increasing, cyclic and sustained loading with additional experimental techniques for the monitoring of the filament ruptures during the tests are scheduled.