SBIR Phase I: Plient Engineered Recycled Steel Fibers as Cheaper, Faster, Safer Concrete Reinforcement

The broader/commercial impact of this Small Business Innovation Research (SBIR) Phase I project includes safer construction, reduction in landfilled tires, >10% lower cost, enhanced durability, and up to 2x faster concrete construction. The innovation, an engineered recycled steel fiber product, can replace conventional steel reinforcing bar (rebar) in certain applications, which will enhance understanding of how fiber characteristics impact key engineering properties. Recycled feedstock with inexpensive mechanical processing used to produce the fibers ensures a durable competitive advantage versus rebar, which is produced by costly melting and forming. In addition to lower upfront cost, the recycled steel fiber technology increases concrete toughness and will lower long-term maintenance costs. The business model for commercializing the recycled steel fiber technology involves bulk purchase of recycled feedstock, transport and mechanical processing, and then sale of the processed fibers to local concrete plants or contractors at a markup. Based on extensive customer discovery, the beachhead markets for the technology include concrete flooring and pavements. The technology will be a key factor enabling commercial success of the company, which was formed specifically in response to the technology. This Small Business Innovation Research (SBIR) Phase I project focuses on eliminating technical barriers inhibiting commercialization of engineered recycled steel fibers for concrete reinforcement. Concrete is traditionally reinforced with steel bars (rebar), which are labor-intensive, costly, and creates dangerous jobsite conditions. The proposed technology addresses each of these limitations, but technical concerns include whether the maximum achievable residual flexural strength of concrete reinforced with the fibers is sufficient for the target applications. Furthermore, the local nature of concrete production requires a robust design tool to determine proper required fiber dosage for a given application based on the concrete composition and properties. This project will elucidate the maximum achievable residual flexural strength and the role of fiber dispersion on limiting the strength and develop a machine-learning tool for determining design fiber dosage. Flexural testing will be performed on a wide range of concrete mixtures and fracture surfaces will be examined for fiber clumping. These test data will be combined with data mining of steel fiber reinforced concrete flexural strength results to train and test the machine-learning based design tool. The results of this project will include understanding of how concrete mixture design and fiber dispersion influences peak residual flexural strength. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.