Reactive transport and damage induced
by crystallisation/precipitation in porous geomaterials

Abstract

Geomaterials are porous, discrete and heterogeneous media exposed to environmental interactions. These materials host multiple fluids with which they establish physico-chemical feedbacks. During the last decades, major shifts in climate and the continued exploration of remote environments encouraged the study of phase transitions within the pores of soils and rocks, which include salt crystallization, mineral precipitation, freeze/thaw dynamics, and methane hydrate dissociation, among others. Phase transitions are a key source of weathering, as they cause unprecedented alterations in the strength and deformation properties of natural deposits. Two major sources of weathering process are envisioned within these projects: haloclasty and freezing/melting cycling.

People

Current people in the group:

Bruno Leclere
PhD Student
Crystallisation-induced damage under confined reservoir conditions

(PhD defense in 2020)

Victor Okumko
MSc/PhD Student
Crystallisation-induced damage in heterogeneous porous media in the context of the erosion of the French Basque coast and the damage of its protection buildings

(MSc defense 15-07-2019)
(PhD defense in 2022)

Antoine Barthes
MSc/PhD Student
Crystallization of water in nanoporous materials and its induced impact on the solid matrix

(MSc defense 07-09-2020)(PhD defense in 2023)

Flavien Thierry
Postdoc fellow
Cast3m modelling of crystallisation-induced damage in heterogeneous porous media

(12 months 2020/2021)

Martín P. Rodríguez
Postdoc fellow
Molecular simulation of fluid confinement and crystallisation effects

(24 months 2020/2022)

Madura Pathirage
Postdoc fellow
Lattice discrete particle modelling of crystallisation-induced damage in heterogeneous porous media

(20 months 2020/2022)

Alumni

Moustafa Sebaa
MSc Student
Crystallisation-induced damage in heterogeneous rocks -Application to haloclasty

(MSc defense 07-09-2020)Now: PhD studentUJF Grenoble, France

Connected publications

Decay processes in buildings close to the sea induced by marine aerosol: Salt depositions inside construction materialsBuildings close to the sea experience different kinds of decay processes related with the influence of marine aerosol. This sea spray is a chemically complex system formed by inorganic salts (sulfates, nitrates and mainly chlorides) and organic matter, together even with airborne particulate matter from the surrounding environment. Buildings close to the sea, erected using different materials such as bricks, plasters, limestones and sandstones, can experience many kinds of chemical reactions promoted by the impact of this sea spray, which favour the formation of salt crystallizations. In this work, a study of salts crystallizing in different kinds of building materials of a construction close to the Bay of Biscay (Villa Belza, Biarritz, France) has been studied in order to evaluate the state of conservation of the materials under study. The construction materials affected by salts were analyzed by means of X-ray Diffraction (XRD) and μ-Raman spectroscopy (μ-RS) for molecular analyses, Energy dispersive X-ray Fluorescence spectrometry (μ-ED-XRF) for elemental analyses and soluble salts tests by means of ion chromatography. These analyses revealed different levels of chlorides, nitrates and sulfates. Moreover, using this methodology, some specific chemical reactions that take place in the Villa Belza were understood. This knowledge can help to lay the foundations for possible future restoration works.
In-situ versus laboratory characterization of historical site in marine environment using X-ray fluorescence and Raman spectroscopyRaman spectroscopy and X-ray fluorescence spectrometry are powerful analytical techniques that allow for molecular and elemental analysis, respectively. Recent developments allowed for the miniaturization of equipment to an extent that in-situ experiments become available. There are many advantages in using portable instruments, but this requires sacrifices regarding the acquisition of the spectra and the quality of the analysis. How much information is lost with this exchange is not clear, neither how important this is for the use of these techniques as forensic tools. In this work, the damage of a façade of Villa Belza, a historic building in Biarritz, France, was evaluated using both portable and benchtop versions of X-ray fluorescence (XRF) and Raman spectroscopy and the approaches were compared. As the comparison of instruments designed for different conditions is not straightforward, the authors use a number of settings to discuss what would be a realistic juxtaposition of results and how this affects the diagnosis of the structure. Furthermore, some hand-held XRF spectrometers are not connected to appropriate software to proceed with the data treatment and the processing of such signals can be tedious or too time consuming. Thus this work also proposes an algorithm for the automatic identification and comparison of elements in the XRF spectra acquired on site. After discussing the trade-off involved with each technique and the respective effect in the limit of detection, the authors conclude that the extra information from benchtop instruments was negligible for this case study.


Connected projects

Newpores - New Frontiers in Porous Materials

Granted by E2S UPPA, NewPores is an international hub dedicated to the mechanics and physics of porous materials, which intends to answer to new Energy and Environment challenges. This is a joint effort of the group on Geomechanics and Porous Materials (G2MP) of the Laboratoire des Fluides Complexes et leurs Réservoirs at E2S UPPA (France), the Centre for Sustainable Engineering of Geological and Infrastructure Materials (SEGIM) at Northwestern University (USA), the University of Vigo (Spain), the Technical University of Madrid (Spain) and University of Liège (Belgium).

Ezponda - Étude des paramètres mécaniques et chimiques à l'origine de l'altération des falaises rocheuses de la côte basque et des ouvrages de défense

Granted by the European Union and the Nouvelle Aquitaine region, Ezponda intends to predict the evolution of the impact and the velocity of coastal erosion under current climate changes and forthcoming sea level rises. In particular, the Ezponda project aims at studying and hierarchizing the different key parameters (haloclasty, rain, storms), which drives coastal erosion and coastal protection building damage. Haloclasty is a natural rock failure process driven by salt crystallisation and salt weathering. It is particularly at sight on coastal areas because it is a key parameter for their natural erosion, which is a crucial social-economic challenge for local authorities in charge of coast management.

ConfCryst - Crystallisation-induced damage under confined reservoir conditions

Although crystallisation-induced damage under environmental conditions has been studied for years, motivated by the interest of the local authorities and restoration companies in salt weathering of historic monuments1-7, few research works have been performed in the geomechanical context of confined reservoir conditions, although fractures correspond to the main damaging process in the upper crustal levels. Granted by E2S UPPA and Total, this project aims at obtaining a better understanding of the mechanism of crystallisation-induced damage under confined reservoir conditions, which is of utmost importance to explain and predict the localisation of cracks and veins in heterogeneous unconventional reservoirs and therefore enhances their characterisation, their stimulation and their production of both conventional georessources as well as sustainable georessources.

CRYSTAL - Combined neutRon and x-raY imaging for the characterization of in Situ crysTallisation-induced crAcking in the context of cuLtural heritage preservation

Crystallization-induced damage contributes majorly to the degradation or weathering of natural building stones, construction materials and our cultural heritage. When saline fluids are present in the pore space of the material, salt crystals might precipitate upon changes in temperature or humidity conditions, leading to salt precipitation on the surface, efflorescence, or to salt crystals precipitating in the pores, subflorescence. The confined crystal growth within the pores might lead to a buildup of crystallization-induced stresses, which can eventually induce fractures in the porous medium. The fracturing results from the interplay of saline flow, salt precipitation reactions and crystallization-induced stresses. The CRYSTAL project, funded by the Communauté d'Agglomération Pau Pyréenées aims at understanding the coupling between those phenomena in order to develop models for advising the building and stone conservation industry.