New analytical models to predict the mechanical performance of steel fiber‐reinforced alkali‐activated concrete

Abstract

The use of alkali‐activated concrete (AAC) as an alternative construction material to Portland cement‐based concrete (PCC) has been widely encouraged by its enhanced mechanical and durability performance and environmental benefits. However, AAC exhibits low flexural and tensile strength, limiting its application in areas where high post‐cracking flexural and tensile load‐bearing capacity are needed. Steel fibers can be added to improve the composite ductility and toughness. Steel fiber‐reinforced alkali‐activated concrete (SFRAAC) is a new emerging technology with research studies evaluating the effect of fiber addition on its mechanical properties still in the early stages. To promote the application of SFRAAC, analytical models predicting their mechanical performance are needed. This study evaluates the applicability to SFRAAC of previously published analytical models developed for steel fiber‐reinforced cement‐based concrete (SFRPCC). Experimental data available in the literature have been collected to create an extensive database to validate and then calibrate these currently available correlations between mechanical properties for SFRAAC. The prediction models considered in this study correlate the mechanical performance of SFRAAC, that is, compressive strength, modulus of elasticity, splitting tensile strength, flexural and residual flexural strength, to the compressive strength of the reference concrete without fibers, the fiber volume fraction and the fiber reinforcing index. Thus, by knowing the performance of the AAC matrix and the fiber properties and dosage, it is possible to predict the overall mechanical behavior of the steel fiber‐reinforced composite.