Effect of multifilament yarn crack bridging on uniaxial behavior of textile reinforced concrete
- Einfluss der Multifilament-Rissüberbrückung auf das einaxiale Verhalten des textilbewehrten Betons
Konrad, Martin Otto Alfred; Meskouris, Konstantin (Thesis advisor)
Aachen : Publikationsserver der RWTH Aachen University (2008)
Dissertation / PhD Thesis
Aachen, Techn. Hochsch., Diss., 2008
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, TRC exhibits a high degree of heterogeneity and imperfections that requires special treatment in the development of numerical models. In particular, the material structure at the micro scale shows a high amount of irregularities and imperfections in the geometrical layout of the basic components and in the quality of local bindings between them. As a result, the damage localization process of TRC exhibits interactions between elementary failure mechanisms in the matrix, in the reinforcement and in the bond. The objective of the work at hand is the development of a framework for the detailed description of the heterogeneity in the material structure of TRC under uniaxial loading including the micro, meso, and macro scale. The framework is constituted by three consecutive models: Fiber Interface Model (FIM), Crack Bridge Model (CBM), Stochastic Cracking Model (SCM). The Fiber Interface Model (FIM) is the basic model component on the micro level. In this model the material- and the bond-characteristics of a single fiber are represented. FIM can be used as a building block in more complex models by parallel and serial coupling. The compound formulation of the material model for the fiber and its interface to the matrix combines plasticity and damage providing the possibility of constructing damage laws including both the fiber strain and the slip between fiber and matrix. The Crack Bridge Model (CBM) employs the FIM for the representation of single filament or groups of filaments with similar properties. Two different approaches are introduced to describe the variation of the material properties. The Statistical Crack Bridge Model (SCBM) reflects the heterogeneity in form of statistical distributions, with the possibility to derive the statistical moments of the response. The Deterministic Crack Bridge Model (DCBM) uses cross-sectional profiles to represent the spatial variability of the material parameters and enables the reproduction of complex interactions and loading histories. The Stochastic Cracking Model (SCM) enables a direct evaluation of the tension stiffening effect during the multiple cracking under uniaxial tensile loading. The combination with the Crack Bridge model (CBM) completes the multi-scale framework by providing an efficient method to transfer the micromechanical characterization of the material structure into the prediction of the tensile behavior on the macro level.