Numerical modelling of the ageing of Ultra High Performance Fibre Reinforced Cementitious Composites

This paper focuses on the experimental characterisation and numerical modelling of mechanical ageing of UHPC. With reference to a specific UHPC mix, conceived in the framework of the Horizon 2020 project ReSHEALience to be used in extremely aggressive environments, the strength and stiffness build-up have been assessed through two experimental campaigns, for both the plain matrix and the fibre-reinforced composite. Then, the tests have been simulated by means of a discrete numerical model, the Multiphysics—Lattice Discrete Particle Model (M-LDPM), improved for capturing the ma-terial ageing in presence of slag in the mixture. The parameters governing the hydration process have been identified through the ONIX model, equally improved to account for the effect of slag. The com-parison between experimental and numerical results has shown that the model well-captures the mate-rial behaviour at each age. The model capability of capturing the material ageing accurately is necessary to distinguish its effect on the mechanical response from those due to other phenomena such as autog-enous or engineered healing.