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Chemical reactions can lead to the expansion of the geomaterial because of the strong precipitation of minerals in the pores of the medium. The quantity and the variability of these reactions led to the development of several chemo-mechanical models. A generic chemo-poromechanical model is proposed to predict both the material degradation induced by various concrete pathologies and the environmental multi-factor impact on the macroscopic swelling. The model is based on the coupling between reactive transport (species diffusion and chemical reactions) and poromechanics. The mineralogy and the poromechanical properties are estimated by a hydration-micromechanics model which allows to consider the material effects. The main applications are dedicated to External Sulfate Attack and Delayed Ettringite Formation of cementitious material at mesoscale. The studies highlight the ability of the model to deal with complex and various phenomena such as coupling chemical reactions with calcium leaching, sulfate sorption and ettringite precipitation, and to consider their impact on the macroscopic expansion. Results also bring out the accuracy of the chemo-poromechanical model to simulate different swelling pathologies. The characteristic crack paths induced by differential strain, material impact, and swelling at the macroscopic scale, fit with experimental observations. [ABSTRACT FROM AUTHOR]

In the context of long-term degradation of porous media, the coupling between fracture mechanics and reactive transport is investigated. A reactive transport model in a cracked discontinuous and heterogeneous porous medium is proposed. The species transport through and along the crack network are taken into account in a multibody approach. A dedicated geochemistry solver is developed and allows to take into account a significant number of chemical reactions. The model is validated via a benchmark for a porous medium without discontinuity. The applications deal with two kinds of chemical attacks in a pre-cracked concrete sample and highlight the impact of the discontinuities in the reactive transport kinetic and on the localization of the chemical degradation. The results bring out that a unidirectional descriptor, such as the depth of ingress rate, is not sufficient to describe the material degradation correctly. [ABSTRACT FROM AUTHOR]

This paper presents and discusses the results obtained by the participants to the benchmark described in de Hoop et al, Comput. Geosci. (2024). The benchmark uses a model for CO2 geological storage and focuses on the coupling between two-phase flow and geochemistry. Several test cases of various levels of difficulty are proposed, both in one and two spatial dimensions. Six teams participated in the benchmark, each with their own simulation code, though not all teams attempted all the cases. The codes used by the participants are described, and the results obtained on the various test cases are compared, as well as the performance of the codes. It is shown that the results obtained are widely consistent, giving a good level of confidence in the outcome of the benchmark. The general complexity of two-phase flow coupled with chemical reactions altering porous media means that some differences between the codes remain. Besides, from the convergence study, it is clear that the two-dimensional problem has a relatively high sensitivity to a spatial resolution which adds to the complexity. [ABSTRACT FROM AUTHOR]