Unified equations to predict residual flexural tensile strength of lightweight steel fiber‐reinforced concrete

In this paper, novel unified equations for predicting the residual flexural tensile strength of normal‐weight, lightweight, and ultra‐lightweight steel fiber‐reinforced concrete (SFRC) are proposed. The unified equations were obtained by conducting multiple nonlinear regression analysis on the test results from 60 notched prism tests conducted according to EN 14651. The proposed unified equations account for fiber geometry, fiber content, concrete compressive strength, and concrete density. Unlike existing prediction equations, which can only predict the flexural tensile strength of normal‐weight SFRC, the proposed equations are applicable for SFRC with varying densities. Test results from the literature verified the accuracy of the proposed equations to within 10% of observed values, on average. Compared to the existing equations, the proposed unified equations were better at predicting residual flexural tensile strength of both normal‐weight and lightweight steel fiber reinforced concrete.