Estimation the flexural-tensile strength of fiber reinforced concrete members

Abstract

Flexural-tensile strength of plain concrete has been measured in terms of modulus of rupture (fr). The computed tensile strength from the flexural-tensile test represents the maximum value at which the plain concrete fractures. Whereas, the tensile strength due to splitting of cylinders represents the concrete true tensile strength (ft), which is less than modulus of rupture (fr). This investigation shows experimental work and numerical analysis to propose a new formula for predicting the modulus of rupture of concrete including steel fiber. The variables considered are: steel fiber content, compressive strength of concrete and steel fiber aspect ratio. The experimental works applied to twenty-one small beam specimens. Furthermore, modes of failure were considered also in this investigation. Experimental findings indicate that the concrete compressive strength, aspect ratio of steel fiber and volume fraction of steel fiber were predominant factors in rupture modulus of fiber reinforced concrete members. Numerical modeling using Finite Element Analysis through thirty-six analyzed specimens was presented. Also, some variables having effects on modulus of rupture were achieved by a parametric study. A new formula for rupture modulus of fiber reinforced concrete was explored and covered for a large range of variations; between 0% to 2.5% in steel fiber content, from 50 to 200 in steel fiber aspect ratio, and between 15 to 50 MPa in compressive strength of concrete.