Influence of concrete strength and fiber properties on residual flexural strength of steel fiber-reinforced concrete

Abstract

The incorporation of steel fiber into concrete is well known to mitigate cracking, thereby improving both the mechanical properties and durability of the concrete. In particular, the post-cracking flexural behavior of steel fiber-reinforced concrete (SFRC) depends on the characteristics of both the concrete matrix and reinforcement fiber . The residual flexural strength obtained from post-cracking responses serves as a fundamental design parameter for SFRC structural elements in design codes and guidelines. Nevertheless, research into the effects of the inherent properties of concrete and steel fiber on the residual flexural strength of SFRC is limited. This paper evaluates the influence of concrete’s compressive strength , fiber content, fiber aspect ratio, and fiber tensile strength on the limit of proportionality (LOP), four levels of residual flexural strength ( f R 1 , f R 2 , f R 3 , and f R 4 ), compressive properties, and fracture energy . Additionally, a database comprised of 887 notched prism test results from the literature was constructed and analyzed to evaluate the key factors that influence the residual flexural strength of SFRC. The test results and database analysis show that the LOP in the flexural response of SFRC depends primarily on the concrete’s compressive strength , whereas the residual flexural strength f R 1 at the serviceability limit state and f R 3 at the ultimate limit state are influenced more significantly by the fiber content, fiber tensile strength , reinforcement index values, and concrete compressive strength . These findings provide a basis for proposing predictive equations for the residual flexural strength of SFRC and serve as essential guidelines for determining the concrete and fiber properties needed to achieve the required performance in SFRC structural elements.

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