Fiber reinforced concrete: Tailoring composite properties with discrete fibers

Concrete is one of the most widely used building materials in the world. The single largest limitation of concrete is its weak and brittle nature under tensile stress. In order to improve this material behavior, reinforcement materials that are strong in tension are embedded into the concrete to avoid brittle failure and increase tensile load capacity. Besides the traditional methods of embedding continuous aligned reinforcement in anticipated zones of tensile stress, random discrete fibers can be dispersed into the concrete during the mixing procedure to create a composite material called fiber reinforced concrete (FRC). In this study, a comprehensive review of the relevant and recent literature pertaining to FRC is provided, establishing basic principles and highlighting the possible contributions to composite properties that different types of fiber can deliver. Once the capabilities and limitations of FRC are well established from previous works, an experimental investigation is conducted, in which flexural testing of 3 different types of synthetic concrete fibers was performed to determine their performance in the fresh state as well as hardened state under flexural loading. The experimental work is then extended to investigate how carbon microfibers and concrete admixtures affect concrete strength development and shrinkage behavior for applications in which high early age strength and shrinkage control is desired. The outcome of this study is anticipated to contribute to the state of FRC knowledge and practice by providing important findings from previous work, supplemented by experimental data which effectively highlights the capabilities that the addition of discrete fibers can impart to concrete