Material Characterization of UHPC with Recycled Fibers and Wires for Future Large-Scale Structural Applications

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Ultra-high performance concrete (UHPC) continues to emerge as a robust concrete solution with enhanced microstructure and superior mechanical behavior compared to normal strength concrete. Many of the high-end UHPC commercial mixtures are proprietary, which limits the opportunities to bring material costs down without going for full non-proprietary mixtures. Nevertheless, whether proprietary or non-proprietary UHPC mixtures are considered, steel fibers remain to be the most expensive component, hindering large-scale applications and mass production. Thus, considering cost effective options or alternatives for steel fibers along with the continuous development of non-proprietary or semi-proprietary UHPC mixtures can be the next big leap in the UHPC world. In this study, recycled fibers and wires derived from landfill tires are considered to provide an alternative component for manufactured steel fibers making the UHPC mixture significantly cheaper, greener, and more sustainable. Full material characterization of UHPC samples is conducted to investigate the effect of recycled steel fibers and wires with different volumetric ratios and compare it against reference samples with traditional high-end manufactured steel fibers. Samples from small batches with different fiber ratios are tested from early and late ages through direct tensile testing using one-inch dog bone specimens and pure axial compression loading using 3×6 in. cylinders. Moreover, results from more samples that will be obtained from an upcoming large-scale pan mixing at precast plant in California, as part of exploring seismic UHPC bridge columns with recycled wires, will also be presented in this paper. The results derived from small and large-scale mixing will be compared, and the research paper will provide preliminary guidelines on effectively using recycled fibers and wires for future large-scale UHPC applications.

Keywords: recycled fibers, direct tension testing, compressive behavior

How to Cite: Romero, A. J. & Moustafa, M. A. (2023) “Material Characterization of UHPC with Recycled Fibers and Wires for Future Large-Scale Structural Applications”, International Interactive Symposium on Ultra-High Performance Concrete. 3(1). doi: