Tensile Behavior of Ultra-High Performance Fiber Reinforced Concrete and Reinforcement Bar

Ultra High Performance Fiber Reinforced Concrete (UHPFRC) is a very resilient material with improved compressive and tensile strength, toughness, durability, and corrosion resistance compared to conventional concretes. Although there is high interest in using this material in the construction industry, the lack of design standards and standardized test methods limit the implementation and application. One critical knowledge gap is seen in understanding the tensile behavior of UHPFRC in combination with steel reinforcement bars. The objective of this research is to fill this knowledge gap. In particular special emphasis has been laid on investigating the effect of fiber volume fraction and fiber orientation. The experimental work is divided into the following three phases: Phase I) Testing separately the uniaxial tensile behavior of UHPFRC and the reinforcement bar. Phase II) Investigating the bond behavior between UHPFRC and reinforcement bars through pullout tests. Phase III) Testing UHPFRC reinforced with reinforcement bars under uniaxial tension. The research effort included tailoring and development of new test methods, optimizing the flow of UHPFRC during casting to orient the fibers parallel, random, and perpendicular to the axis of applied loading, testing an extensive number of specimens and analyzing the experimental data