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MECHANICAL BEHAVIOUR OF A ULTRA-HIGH PERFORMANCE FIBRE REINFORCED CEMENT COMPOSITE SUBMITTED TO IMPACT LOADING CONDITIONS Pierre Rossi and Edouard Parant Laboratoire Central des Ponts et Chaussées, Paris, France Abstract The multi-scales fibre reinforcement of this cement composite is characterized by the gradual and continuous activation of the various fibres scales until the peak strength. The studied material can be modelled as an elasto-plastic one with positive work hardening in tension. In order to cover a large range of loading rate, two dynamic tests are carried out using two four points bending test device on thin slabs: an hydraulic press and a block bar device. Results indicates that the modulus of rupture increases by 25 percent in the range of quasi-static loading rate [1.25x10 -4 - 1.35 GPa/s], and that strength is quadrupled for loading rate superior to 500 GPa/s. Results indicate that this new material is more sensitive to the loading rate effects than all others cement materials. The direct tensile strength increases by about 1.5 MPa/log 10 unit under quasi-static loading. Keywords: cement composite, impact; multiscale fibre reinforcement; stress rate effects, ultra-high performance, steel fibres. 1. INTRODUCTION For a few years, the Laboratoire Central des Ponts et Chaussées (LCPC) has worked on the development of new cement composites. These materials are the direct implementation of the "Multi-Scale Fibre Reinforcement Concept" developed by Rossi [1], [2]. The idea is to mix short fibres with longer fibres in order to intervene at the same time on the material scale (increase of the tensile strength) and on the structure scale (increase
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MECHANICAL BEHAVIOUR OF A ULTRA-HIGH PERFORMANCE FIBRE REINFORCED CEMENT COMPOSITE SUBMITTED TO IMPACT LOADING CONDITIONS

Jun 24, 2023

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