Iowa Statewide Urban Design and Specifications

About the research

Inclusion of randomly-oriented, discrete fibers in cementitious materials is proven to enhance many of the desired engineering properties, such as fracture toughness, flexural strength, and resistance to the formation and propagation of micro/macro cracks under extreme loads, in addition to reducing the risk of early-age cracks in concrete. The concrete fibers can be broadly categorized to metallic and non-metallic fibers. Among their differences, non-metallic fibers offer high corrosion resistance, in contrast to metallic fibers, which are vulnerable to corrosion, despite offering superior mechanical properties.

This project aims to conduct a holistic investigation of a hybrid of metallic and non-metallic fibers to introduce expected functionalities to fiber-reinforced cementitious materials, especially ultra-high performance concrete (UHPC). Use of alternative fibers for non-structural UHPC applications will particularly reduce costs and eliminate the need for Buy America as required with steel fibers. Considering the latest fiber products available in the market, this project will investigate the promise of a new generation of UHPC mixtures engineered by appropriate choices and dosages of fibers. Based on a suite of laboratory investigations, the ultimate goal of this project will be to develop practical guidelines to select a hybrid of metallic and non-metallic fibers for non-structural UHPC. The fiber selection criteria will be consistent with target applications, providing the desired mechanical and durability properties, paired with high corrosion resistance and adequate bond with the cementitious matrix.