Fiber orientation in viscous fluid flow with and without vibration

This early-stage investigation is related to determination of flow speed gradients of fresh steel fiber-reinforced concrete (SFRC). They are assumed to be the key parameters for computer modeling of orientation of steel fibers in form casting process. The aim of the research is to elaborate a computer model for evaluation of steel fiber orientation in casting process, which would provide an attractive possibility to predict concrete mechanical properties, optimization of casting process and costs due to proper use of ingredients. Fiber orientation in FRC is important for ensuring the best mechanical properties in the places where it is necessary. Task can be solved as: to obtain optimal fiber concentration and orientation or to use appropriate casting approach of concrete with the goal to obtain required mechanical properties in appropriate locations of the composite element. As an example the paper considers the case of trench filling by fiber concrete. Simulations provided distributions of vertical and horizontal velocities in real-time scale. Behavior of a single fiber in an inclined container with a viscous transparent liquid (potato-starch solution) was analyzed in order to confirm the possibility to obtain orientation of fibers on the basis of velocity gradients in viscous fluid. For precise modeling of potato-starch liquid, coefficient of dynamic viscosity was determined. The experiments performed on fibers in an inclined container demonstrated satisfactory agreement with the simulation results. Performed analysis indicates that velocity gradients can be applied for determination of position and orientation of fibers in fabrication of fiber-reinforced concrete products