Experimental Investigation of Mechanical Properties of UHPFRC

This paper describes experimental investigations of various mechanical properties of Ultra High Performance Fiber Reinforced Concrete (UHPFRC). The UHPFRC is a modern cementitious composite containing a large amount of cement, both reactive and nonreactive very fine particles, chemical admixtures and short high strength steel fibers. This type of concrete has superior durability and excellent mechanical properties. In this paper an UHPFRC containing 2% of fibers by volume with a compressive strength exceeding 150 MPa is presented. In this study detailed descriptions of the measurements of compressive strength, bending strength, direct tensile strength, fracture energy and modulus of elasticity are given. The study provides a comparison of the above mentioned UHPFRC properties with high performance concrete, fiber reinforced concrete and conventional structural concrete. The results indicate excellent performance of UHPFRC in all categories. The biggest difference to ordinary concretes can be seen in tensile behavior, where its response in tension exhibits strain hardening accompanied with multiple cracking followed by tensile softening. The direct tensile strength of the studied material is 10 MPa and its fracture energy is 5 times higher than that of conventional fiber reinforced concrete. It is believed, that such type of material is the future of concrete industry, it will allow executing higher, more effective structures with excellent durability.