Variation of Flexural Performance Parameters Depending on Specimen Size and Fiber Properties

Abstract

The use of steel fiber–reinforced (SFR) cement based materials for semistructural applications is expected to increase because some design codes propose such methods for design. The first step for the steel fiber–reinforced concrete (SFRC) design is using correct parameters for material properties. The behavior of concrete under compression and tension is evaluated by using standards. The tension behavior of concrete materials is evaluated, most of the time, via bending tests because these tests are relatively less cumbersome when compared to direct tensile tests. The existing standards/codes suggest using different geometries and set-ups for evaluating bending performance because very different geometries are being used in the structural design. Studies have been conducted by researchers to understand the parameters affecting the results obtained from the bending tests. In this study, the effects of varying shear span-to-depth ratios (a/d) and specimen depth to steel fiber length ratios (d/fL) on the most used design parameters [i.e., the equivalent bending strength (EBS) and bending strength ratio (EBR)] were studied with different steel fiber types and amounts, and the results were discussed based on current standards limitations on size and the d/fL ratio. A thorough evaluation of the fresh and hardened state properties was carried out for a full understanding of material properties, and a detailed fiber orientation density analysis was also done for the correct evaluation of the flexural test results.