UHPFRC tensile behavior characterization: inverse analysis of four-point bending test results

The tensile stress-strain response of ultra-high performance fiber reinforced concrete (UHPFRC) is a fundamental constitutive property, and reliable knowledge of this response is necessary for appropriate application of the tensile-carrying capacity of such advanced cement-based materials. Flexural test methods, whose implementation is well established, present a test procedure capable of assessing this property. Nevertheless, these methods provide indirect information and need to be complemented by inverse analysis in order to quantify the intrinsic tensile behavior of tested materials. Moreover, bias or scatter can be induced when simplified constitutive laws are assumed for the analysis. Flexural tests have been completed on multiple types of commercially available UHPFRC. A new inverse analysis method is presented and qualified, compared with existing methods, and also compared with results from direct tensile tests. Advantages and limitations of the experimental and analysis methods have been derived.