Investigation of mechanical properties of ultra high performance concretes under various fibers

Ultra High Performance Concrete (UHPC) is a type of concrete that has attracted attention with its advanced engineering properties, boasting high strength and durability. This type of concrete is preferred for structures requiring long-lasting durability, constructed using binder materials, fine aggregates, and additives. Unlike traditional concrete, UPC can contain special additives and fibers. The various fibers incorporated into UPC can significantly improve the concrete's mechanical properties. These mechanical properties include compressive strength, flexural strength, tensile strength, impact resistance, and abrasion resistance. The fibers used prevent the spread of microcracks within the concrete, ensuring longer durability. Other factors contributing to the high strength of UPC include the fine aggregates and the properties of the water/binder ratio. These materials increase the density of the concrete, limiting water movement within the concrete and increasing its strength. The fibers increase the concrete's tensile strength, helping to prevent adverse events such as cracking and breakage. Fibers are known to strengthen structural integrity and increase durability by preventing microcracks in the internal structure of concrete. In ultra-high-performance concrete, high cement content is the primary determinant of both strength and durability. It also increases the density of the matrix, reducing the void ratio, and thus resulting in a more compact structure. The aim of this study is to investigate the mechanical behavior of ultra-high-performance concretes when combined with various fibers (steel fiber, basalt fiber, and microfiber). In this study, basalt fiber, steel fiber, and microfiber fiber were added to UHPC at 0.5%, 1%, 1.5%, and 2% by volume to 150x150x150 mm cube samples. Their compressive and splitting tensile strengths were experimentally investigated at 7, 28, and 56 days.