Advancing Ultra High Performance Concrete: Evaluation of Recycled Tire Steel Fibers and Rice Husk Ash for Enhanced Sustainability and Performance

Abstract The limited availability of conventional materials used in producing Ultra High Performance Fibre Reinforced Concrete (UHPFRC), such as steel fibers, silica fume, and quartz sand, has restricted its widespread application in construction. This research explores the development and Charaterization of UHPFRC using environmentally friendly, locally available materials—specifically rice husk ash (RHA) and recycled tire steel fibers—in accordance with ASTM standards, to promote sustainability and improve waste management practices. The study examines the effects of varying fiber content and length on the Flowability, Tensile and compressive properties of UHPFRC. A Taguchi Method design of experiment was adopted to optimize the concrete mix formulations. Test results indicate that the spread flow of the mix, measured as per ASTM C1437, decreased with increasing fiber content and length, with ranges of 292–271 mm, 310–246 mm, and 285–239 mm for 13, 16, and 19 mm fibers, respectively. The compressive strength, tested according to ASTM C39, reached a maximum of 107.9 MPa on the 28th day for a mix containing 3% of 13 mm straight recycled tire steel fibers, placing it within the UHPFRC strength class (≥ 100 MPa). Furthermore, an increase in fiber content and length significantly enhanced the tensile strength of the concrete, achieving up to 64.6% higher strength than plain concrete with 4% fiber addition of 16 mm straight fibers, following ASTM C1609 standards. These findings demonstrate the potential of using RHA and recycled tire steel fibers not only in producing high-performance UHPFRC but also in advancing waste management by repurposing agricultural and industrial by-products, thus offering a sustainable alternative for durable infrastructure development.