Tensile characterization of Ultra-high performance fiber-reinforced concrete with digital images correlation

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Ultra-high performance fiber-reinforced concrete (UHPFRC) is an advanced cementitious composite that**exhibits superior mechanical properties compared to traditional or even high performance concrete (HPC).**Those mechanical properties, combined with an excellent durability, make UHPFRC a very interesting choice**for the rehabilitation of existing concrete structures as well as the development of slim and lightweight**concrete structures. Tensile characterization of UHPFRC is mostly made with the use of an indirect tensile test.**The results are then either directly used to classify the material according to the different standards or**post-processing is needed to convert the raw data into a coherent law. Some direct tensile tests (DTT) are**proposed for UHPFRC characterization. The use of direct tensile test allows the direct characterization of the**tensile law of the material without having to correct the data, which is needed with an indirect test. However,**the setup required to perform those tests are complex and, even in the best conditions, results vary largely from**different samples of the same material. This research project focuses on the development of a state-of-the-art**direct tensile test (DTT) for the tensile characterization of UHPFRC or any other fiber-reinforced cementitious**composites, such as the engineered cementitious composite (ECC) and the high-strength high-ductility**composites (HSHDC). The experimental setup will be mostly based on the latest DTT developed at the École**Polytechnique de Lausanne (EPFL). Digital images correlation will be used to capture the formation of micro**and macro cracks during the strain-hardening and strain-softening phases and will help enhance our**comprehension of this phenomenon.