“…The expansion factor f} was taken to be 1.0, as found in the literature [1,2,21], although other studies consider a greater expansion of the oxide [22,23]. For the normal stiffness, a wide range of values are found in the literature: in [2], the bulk modulus of the oxide was taken to be of the same order of magnitude as the bulk modulus of water (around 2 GPa); in [23,24] the elastic modulus was estimated from a combination of analytical models and experiments in which the radial displacement in concrete was measured by image correlation techniques; the values obtained in these two studies are, however, very different: an elastic modulus of 0.14 GPa is reported in [23] for an assumed Poisson's ratio of the rust of 0.2, while the values of the elastic modulus reported in [24] range between 2 and 20 GPa, and no reference to Poisson's ratio was made by the authors. In the present paper, a fluid-like behavior is assumed, similar to that proposed by Molina, Alonso and Andrade in [2], with bulk modulus of rust of 2 GPa, and a vanishing small shear modulus; a few calculations were also run with bulk modulus equal to 0.2 GPa, and to 20 GPa, to test the sensitivity of the results to large variations of this parameter (see Section A for the details).…”