Experimental Characterization of the Tensile Constitutive Behaviour of Ultra-High Performance Concretes: Effect of Cement and Fibre Type

The Research Project ReSHEALience has been launched in 2018 in the framework of the European Programme Horizon 2020. The project aims at developing a new approach for the design of structures exposed to extremely aggressive environments, based on durability and life cycle analysis. In this regards, the starting point is represented by new advanced Ultra-High Performance Fibre Reinforced Cementitious Composites (UHPFRCCs), called Ultra-High Durability Concretes (UHDC) because of their enhanced durability obtained by means of engineered composition, which should be characterized by strain hardening behaviour under tension in both ordinary and very aggressive conditions. In this context, the first step is to develop an effective approach for identifying the main parameters describing the overall behaviour in tension. In the present study, indirect tension tests have been performed via 4-Point Bending Tests (4PBT). Starting from the test results, a combined experimental-numerical identification procedure has been implemented in order to evaluate the effective material behaviour in direct tension in terms of stress-strain law. Finally, the comparison among three mixes differing for fibre and cement type is reported in terms of tensile response and post-crack localization behaviour.