Fiber content and curing time effect on the tensile characteristics of ultra high performance fiber reinforced concrete

Ultra high performance fiber reinforced concrete (UHPFRC) is a concrete type with superior mechanical properties and of a relatively high tensile strength. The tensile stress-strain characteristics of UHPFRC are highly affected by the mixture design and the curing regime. In this study, an extensive experimental investigation has been conducted with direct tensile tests on a number of specimens that contained different percentages of steel fibers and different cement types were applied. Also, various curing regimes were investigated. Different models depending on the steel fiber amount were proposed for the simulation of the stress-strain and the stress-crack opening response of UHPFRC, while the fracture energy was also calculated for the different fiber contents. Finally, the effect of fiber content and curing time on the variation of the experimental results are discussed.