Flexural Strength Assessment of Steel Fiber Reinforced Concrete

Abstract

Using the details of a previous study in which the flexural response of steel fiber reinforced concrete (SFRC) was accurately predicted from a constitutive model, explicit expressions for the first crack and the ultimate flexural strength are derived in this paper. In the present analytical model, the direct tensile strength, residual strength, and the product of bond strength τd and fiber aspect ratio (L/d) are used as parameters in the investigation. The “bond-aspect ratio” index τd(L/d) and fiber volume fraction play important roles in influencing the flexural behavior of SFRC. Calculated flexural strengths using the derived explicit expressions are compared with experimental data on SFRC beams and slabs. Good agreement between calculated strengths and experimental data is obtained. To further simplify the ultimate strength prediction, studies on the behavior of basic parameters [fult, ft, and τd(L/d)] for a range of practical fiber volume concentration Vf were conducted, and from which a simple expression is derived. Predictions using the simplified ultimate strength expression are compared with results obtained from the above analytical procedure and with experimental data. The approaches serve as an effective tool for flexural strength assessment of SFRC.