Ultra-high performance fibre-reinforced concrete under impact: experimental analysis of the mechanical response in extreme conditions and modelling using the Pontiroli, Rouquand and Mazars model

Abstract

To evaluate the vulnerability of ultra-high performance fibre-reinforced concrete (UHPFRC) infrastructure to rigid projectile penetration, over the last few years CEA-Gramat has led an experimental and numerical research programme in collaboration with French universities. During the penetration process, concrete is subjected to extreme conditions of pressure and strain rate. Plasticity mechanisms as well as dynamic tensile and/or shear damage are activated during the tunnelling phase and the cratering of the concrete target. Each mechanism has been investigated independently at the laboratory scale and the role of steel fibres especially has been analysed to understand their influence on the macroscopic behaviour. To extend the experimental results to the structural scale, penetration tests on UHPFRC slabs have been conducted by CEA-Gramat. The analysis of this dataset combined with material characterization experiments allows the role of steel fibres to be identified in the different plasticity and damage mechanisms occurring during penetration. In parallel, some improvements have been introduced into the concrete model developed by Pontiroli, Rouquand and Mazars (PRM model), especially to take into account the contribution made by the fibres in the tensile fracture process. After a primary phase of validation, the capabilities of the PRM model are illustrated by performing numerical simulations of projectile penetration into UHPFRC concrete structures.This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'.

Prediction of perforation into concrete accounting for saturation ratio influence at high confinement

“…In case of hard impact, various empirical formulae were proposed to predict the ballistic limit or the penetration depth into concrete and RC targets. Among them, Berriaud et al [26] proposed a perforation limit formula, whose range of validity has been extended later [29], taking into account the missile nose shape influence. The effects of the projectile nose shape on the extent of local damage were also investigated experimentally in case of soft impact [30].…”

“…Berriaud's model [26] or derived ones are based upon the uniaxial compressive strength after 28 days. Baroth et al [4] and Zingg et al [34] have shown that latter parameter is a poor indicator of concrete compressive strength under high confinement.…”

“…Thanks to these tests performed on IRIS HPC [12] [15], the coupled damage plasticity model PRM proposed by Pontiroli et al [24] had been slightly revised [15]. This last version accounts for strain rate, Lode angle and tensile damage [26].…”

Brittle materials at high-loading rates: an open area of research

“…The PRM damage model is coupled to the plasticity model proposed by Krieg [61] and Swenson & Taylor [62]. In this theme issue, the PRM model is used to numerically simulate the penetration process of a rigid projectile striking an ultra-high-performance fibre reinforced concrete structure [23]. As an alternative, the lattice discrete particle model can be used to simulate the dynamic behaviour of concrete by postulating interaction laws of a system of discrete polyhedral cells belonging to coarse aggregate particles or to the cementitious matrix of the concrete [63].…”

“…10 3 -10 6 s −1 according to LaLone & Gupta [41] and Zinszner [42]). More recently, this testing facility was used to investigate the tensile strength of an alumina ceramic [13], two SiC ceramics [14] ( figure 3a) and an ultra-high-performance concrete [23].…”