22 Size effect on the flexural performance of ultra high performance fiber reinforced concrete (UHPFRC)

Abstract

Ultra High Performance Fiber Reinforced Concrete (UHPFRC) is a relatively new material with enhanced mechanical properties. The tensile performance characteristics are predominant of the high energy absorption and toughness. The actual stress-strain model in tension can be determined by direct tensile tests. However, it is not always feasible to conduct direct tensile tests and a common practice is to perform indirect tests such as the flexural testing of standard prisms. The tensile characteristics of Steel Fibre Reinforced Concrete (SFRC) can be calculated using the flexural testing results in conjunction with models from the literature. However, until now there are not any relevant published models on UHPFRC. In this study the results of an extensive experimental program have been used to investigate the ‘size effect’ of UHPFRC. Prisms with different cross-sectional depths have been tested together with dog-bone shaped UHPFRC specimens in direct tension. These results have been analyzed and a model is proposed for the correlation of the tensile strength with the respective flexural strength of UHPFRC prisms with various depths.