Influence of the fiber orientation and fiber distribution on the load carrying efficiency of steel fibers in fiber reinforced concrete

摘要

Most design codes for steel fiber reinforced concrete assume that the fibres are uniformly spread within the concrete and that there is an even distribution of all fibre orientations. However, the orientation of fibres within the concrete has great effect on their effectiveness. In this work, the influence of the fiber orientation and fiber distribution on the efficiency of the fibers is investigated. The investigation starts with advancing and evaluating existing models in order to calculate theoretical fiber orientation factors for arbitrary member geometries. With these theoretical values it is possible to asses the efficiency of steel fibers, and to compare test results of different specimens. To check the model, bending tests on different specimens of steel fiber reinforced concrete have been performed. Also fiber counts in saw-cut surfaces were evaluated. It became evident, that the model fits well to the first test results. Theoretical orientation factors therefore are very helpful for interpreting test results. However, more tests need to be done in order to learn more about the scatter of the results.