To what extent does the fiber orientation affect mechanical performance?

• Flow length and flow thickness affect fiber orientation.
• Mechanical performance vary depending on fiber orientation state and other factors.
• The extent to which fiber orientation affect resulting mechanical performance.
• Implementation of the results on the design of fiber-reinforced cement-based materials.

Design of fiber-reinforced structural elements rose as a need in the last decades with an increasing use of fibers in concrete. Fiber orientation is an important phenomenon and it was shown that fiber orientation state effects mechanical performance to some extent. Measuring fiber orientation state is possible, unfortunately is not yet sufficient to predict mechanical performance. Therefore, relatively new guidelines used for design of fiber-reinforced elements propose using representative specimens which mimic real structures to pre-evaluate structural performance. In the present research the effects of various parameters on fiber orientation state was investigated and a comparison was made by using the results obtained from related literature. The comparison showed that similar orientation states could be obtained by following pre-defined procedures. Yet, that does not provide similar mechanical performances. To predict mechanical strength, research should concentrate on combining different factors that affect resulting performance.