Job Offers

• THE CORROSION OF REINFORCEMENT AND THE DURABILITY OF REINFORCED CONCRETE STRUCTURES IN COASTAL AREAS

  PROPOSAL FOR A DOCTORAL CONTRACT FOR OCTOBER 2025

  SUBJECT: EVALUATION OF THE CORROSION OF REINFORCED CONCRETE IN MARINE OR ATMOSPHERIC ENVIRONMENTS THROUGH NEW ELECTROCHEMICAL APPROACHES

  Application deadline: May 15th, 2025

  THESIS LOCATION: La Rochelle University and Gustave Eiffel University – Marne-la-Vallée Campus (France).

  CONTEXT:
  The proposed thesis concerns the corrosion of reinforcement and the durability of reinforced concrete structures in coastal areas. The aim of this study is to investigate new, reliable electrochemical approaches for assessing the progress of reinforcement corrosion. This will provide a better understanding of corrosion mechanisms in reinforced concrete and, consequently, extend the service life of structures, in addition to reducing the cost and environmental footprint of maintaining these structures. In addition, the study will focus on cementitious
  materials containing mineral additives, which are by-products of the industry. These additives are generally used to replace part of the cement used in concrete. Their use will make it possible, on the one hand, to recover these industrial wastes, and on the other, to reduce the use of cement and contribute to the reduction of CO2 emissions and the environmental impact of structures in coastal areas.

  Although the issues at stake here may be considered global, they nevertheless have a strong local resonance.

  Reinforced concrete structures on the Charente Maritime coast - such as the Oléron bridge, the Ré bridge and port infrastructures in La Rochelle - are starting to look old and are suffering from corrosion-related degradation.

  With this thesis, new electrochemical approaches will be proposed to more effectively assess the corrosion of reinforcement in these reinforced concrete structures. Ultimately, these improvements will make it possible to understand the behavior of structures in maritime areas (corrosion resistance), and consequently extend their service life by optimizing maintenance/repair decisions.

  SUBJECT DESCRIPTION
  Reinforcing bars in reinforced concrete, generally made of carbon steel, are embedded in a highly alkaline, porous solid medium. In this environment, the steel is passivated and covered with a protective oxide film of nanometric thickness. Over time, reinforcement corrosion can occur either when chloride ions reach the reinforcement above a certain concentration, or when CO2 from the ambient air carbonates the concrete coating, causing a drop in its pH. Steel corrosion will lead to a reduction in reinforcement diameter, cracking of the concrete (iron corrosion products are more voluminous than iron metal) and a reduction in steel/concrete adhesion. Cracking of the concrete coating will accelerate the arrival of aggressive agents on the metal. All these phenomena can lead to a reduction in its load-bearing capacity, thus weakening the structure.

  The national project PerfDuB (2015-2022), for Performance-Based Approach to the Durability of Concrete Structures, initiated a large scientific program in 2019 considering a combined analysis of the performance-based approach (study of transfer reactions in the cover concrete) and the corrosion approach (study of the corrosion resistance of steel reinforcements in concrete). This program, funded by IREX, involved several laboratories: the Experimentation and Modeling Laboratory for Civil and Urban Engineering (EMGCU) at Gustave Eiffel University, the Engineering Sciences Laboratory for the Environment (LaSIE) at La Rochelle University, the Research Laboratory for Historical Monuments (LRMH), and the Center for Studies and Research in the Concrete Industry (CERIB). Several hundred centimeter-scale reinforced concrete specimens, made with different reinforcements and various cement formulations (controls, with chloride during mixing or after carbonation to accelerate corrosion), have been manufactured and placed in various environmental and climatic conditions.

  During the National APPLET project (2007-2010), an initial corrosion monitoring study of reinforced concrete prisms manufactured with CEM I cement) was carried out and corrosion simulation and prediction results were proposed. The national PerfDuB project (2015-2022), for Approche Performantielle de la Durabilité des ouvrages en Béton, has initiated a wide-ranging scientific program in 2019, considering a combined analysis of the performantial approach (study of transfer reactions in embedding concrete) and the corrosion approach (study of the corrosion resistance of steel reinforcement in concrete). This IREX-funded program involved several laboratories: the Laboratoire Expérimentation et Modélisation pour le Génie Civil et Urbain (EMGCU) at Gustave Eiffel University, the Laboratoire des Sciences de l'Ingénieur pour l'Environnement (LaSIE) at La Rochelle University, the Laboratoire de Recherche des Monuments Historiques (LRMH) and the Centre d'Études et de Recherches de l'Industrie du béton (CERIB). Several hundred centimeter-scale reinforced concrete specimens, made of different reinforcement and with different cement formulations (control, with chloride in the mix or after carbonation to accelerate corrosion), were manufactured and placed in a variety of environmental and climatic conditions.

  - In La Rochelle, at 2 sites: the Minimes port (permanently immersed in seawater) and the platform at the foot of the St. Nicolas Tower (in a tidal zone).
  - At Gustave Eiffel University based on temperature and relative humidity pairs (Temperature 20 or 45°C, RH = 60%, 80%, and 92%) and natural outdoor conditions.
  - At CERIB, based on temperature and relative humidity pairs (Temperature 20 or 45°C, RH = 60%, 80%, and 92%) and cycling conditions and natural outdoor conditions.

  Since the start of this program, several experimental electrochemical measurement campaigns have been carried out on reinforced concrete prisms by the various partners. Initial results suggest that corrosion processes are not yet at work on most of the specimens, with the exception of a few subjected to natural atmosphere and the 45°C - 92% RH binomial. In fact, the concrete is still too “young” to have carbonated and thus reduced its alkalinity. Moreover, chlorides from the marine environment do not yet appear to have reached the
  reinforcement in the case of specimens containing no chloride at the time of mixing. However, the electrochemical measurements commonly applied in the study of reinforced concrete (sponge or submerged measurements, Open Circuit Potential - OCP, Polarization Resistance - Rp and Electrochemical Impedance Spectroscopy - EIS) carried out on all these prisms are not always consistent with each other. The electrochemical processes involved are far more complex than envisaged, and require a more fundamental approach to
  understanding the mechanisms and their responses to electrochemical measurements.

  The aim of this thesis work is to carry out non-destructive (ND) electrochemical measurement campaigns on various reinforced concrete prisms in a chloride environment (at La Rochelle and Eiffel University) and in a carbonation environment (at CERIB). The aim is to propose a new, robust electrochemical method that takes account of measurement conditions (immersion of the specimen or use of a sponge, electrochemical characterizations (CV or EIS)) and contamination conditions (chloride or carbonation), enabling us to assess the
  corrosion processes at work within the different concretes. Results will be analyzed according to climatic conditions. To validate the ND results, destructive tests will be carried out on selected prisms to characterize the surface condition of reinforcement at the steel/concrete interface and identify the corrosion products that have developed. To this end, the characterization techniques available at LaSIE, such as Raman micro-spectrometry, X-ray diffraction and X-ray tomography, will be employed. Observations using Scanning Electron Microscopy and EDS will be carried out at LRMH, a partner in the project. Based on the results obtained, the aim in fine will be to simulate and predict corrosion as a function of climatic conditions and aggression.

  PROFILE
  The PhD candidate could come from a Master's degree in Materials Science and Engineering or other national engineering training, particularly in the field of electrochemistry and materials. The candidate should show an interest in experimentation and the management of experimental data sets. He/she must be mobile (the thesis will be carried out in La Rochelle and Marne la Vallée), organized, rigorous and have good oral and writing skills in French and English. Knowledge of electrochemistry is essential.

  Thesis supervision
  - Dr. Marc JEANNIN, Senior Lecturer - HDR in the Engineering Sciences for the Environment Laboratory (LaSIE) at La Rochelle University
  - Dr. Véronique BOUTEILLER, Director of Research - HDR in the Experimentation and Modeling for Civil and Urban Engineering Laboratory (EMGCU) at the Gustave Eiffel University - Marne-La-Vallée Campus and Director of the “DECISION” Scientific Chair supported by the Gustave Eiffel University Foundation.
  - Dr. Philippe TURCRY, Senior Lecturer - HDR at the Laboratory of Engineering Sciences for the Environment
  (LaSIE), La Rochelle University.

  Additionally, the doctoral student will be surrounded by a team of researchers at LaSIE (4 Associate Professors), at the EMGCU Laboratory (1 Research Director + 1 Assistant Researcher), at CERIB (1 Research Engineer), and at LRMH (1 Research Engineer), from whom they can rely on and benefit from each other's expertise.
   

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• CHAIRE de Professeur(e) Junior CNRS” (a five-year CNRS researcher position) entitled ‘Sustainable Materials (DURAMAT)’

  CIRIMAT (UMR CNRS 5085) is one of four laboratories selected by CNRS Chimie to potentially host a “Chaire de Professeur(e) Junior CNRS” (a five-year CNRS researcher position) entitled ‘Sustainable Materials (DURAMAT)’.

  The scientific theme of this CNRS researcher position is the durability of materials under severe conditions of use, a field in which CIRIMAT has a recognised national and international reputation.

  CIRIMAT will particularly support applications demonstrating expertise in aqueous corrosion, stress corrosion cracking and hydrogen embrittlement, although all other applications in the field of metallic materials durability are welcome.

  The teaching associated with this five-year CNRS researcher position will take place at ENSIACET, an engineering school of Toulouse INP.

  This position concerns experienced researchers (PhD +6) and opens the way to a possible tenure-track CNRS position as Director of Research (equivalent to Full Professor) within 5 years of taking up the position.

  A description of CIRIMAT's activities, particularly in the field of metallic materials durability, is available on the website : http://https://cirimat.fr

  Candidates are advised to contact CIRIMAT in order to develop a project that is consistent with the context of the “Chaire de Professeur(e) Junior CNRS” on the one hand, and the laboratory's expectations on the other.

  To do so, please contact: Professor Christine Blanc. (christine.blanc@ensiacet.fr).
• STAGE MASTER 2

  DÉBUT DU STAGE DE 6 MOIS : entre le 1er février 2025 et le 1er mars 2025 (selon retour ZRR, procédure Sécurité-Défense)

  CV ET LETTRE DE MOTIVATION SONT À ADRESSER AVANT LE 4 DÉCEMBRE 2024 A 18h00 (Paris).

  Le CIRIMAT / UMR CNRS 5085 (INPT - ENSIACET Toulouse) et RTE (Paris) recherchent un(e) candidat(e) pour un stage Master 2 (6 mois) intitulé : 

  TRANSPORT D'ÉNERGIE ET DURABILITÉ. ÉTUDE DU VIEILLISSEMENT D'UN CÂBLE AÉRIEN.

  Le secteur de l’énergie est plus que jamais aujourd’hui un secteur stratégique pour l’économie d’un pays. En France, l’une des principales missions de RTE est d’assurer l’intégrité du réseau de transport d’électricité et en particulier des câbles aériens. Environ deux tiers du réseau de RTE est composé de câbles en alliage d’aluminium de la série 6xxx (almélec) dont il est primordial d’évaluer et maîtriser le vieillissement. Le stage proposé sera réalisé en parallèle d’une thèse qui a débuté en décembre 2023. Dans le cadre de cette thèse, il s’agit d’étudier l’endommagement en corrosion des câbles aériens en intégrant les aspects vieillissement microstructural et sollicitations mécaniques. La durabilité de câbles aériens en almélec est donc analysée en situation de couplage : état microstructural / environnement / état de contraintes. L’objectif à terme est d’identifier des marqueurs du vieillissement des câbles pour permettre à RTE d’assurer le contrôle du réseau de transport d’électricité. Cela suppose d’intégrer des problématiques de vieillissement thermique, corrosion et corrosion sous contrainte des câbles. Depuis 1 an, le doctorant a bien avancé l’étude du vieillissement microstructural des câbles et il a commencé à aborder la problématique du comportement en corrosion.

  Le stage de Master 2 est proposé pour approfondir l’étude du vieillissement microstructural des câbles en alliage de la série 6xxx sous sollicitations thermiques monotones et/ou cycliques. Il s’agit de compléter les observations réalisées de façon à être en mesure de proposer des explications consolidées des évolutions observées et de déterminer l’impact de ces dernières sur les propriétés mécaniques des échantillons.

  Le travail à réaliser peut être décrit en trois phases :
  - phase 1 : Étude bibliographique visant à dresser un état de l’art quant à la microstructure des alliages de la série 6xxx, et les évolutions de microstructure attendues sous sollicitations thermiques et de leur impact en termes de propriétés mécaniques.
  - phase 2 : Étude du vieillissement microstructural de câbles aériens en alliage de la série 6xxx sous sollicitations thermiques monotones et cycliques. Ce travail sera réalisé sur la base d’observations en microscopie optique, électronique à balayage et en transmission, mais aussi de caractérisation par EBSD. Des analyses en DSC seront aussi réalisées, et un banc de résistivité électrique sera mis en oeuvre pour analyser les transformations microstructurales se produisant au cours des différents cycles thermiques appliquées.
  - phase 3 : Détermination des propriétés mécaniques des échantillons en fonction de leur état microstructural.

  Profil du candidat : Le(la) candidate devra posséder de solides connaissances dans le domaine des matériaux métalliques. La personne recrutée devra également apprécier l'expérimentation et le travail en équipe.

  Salaire : 1373 € net / mois si la situation administrative du (de la) candidat(e) permet un recrutement en CDD. Sinon, il s’agira d’indemnités de stage telles que prévues par la loi.

  Lieu : CIRIMAT.

  Les candidatures (CV + Lettre de motivation) sont à adresser avant le 4 décembre 2024 à 18h00 (Paris) à :

  christine.blanc@toulouse-inp.fr - Tél. : +33(0)5 34 32 34 07

  moukrane.dehmas@toulouse-inp.fr - Tél. : +33 (0)5 34 32 34 40

  stephane.heurtault@rte-france.com - Tél. : +33 (0)1 79 24 82 88

  julien.said@rte-france.com - Tél. : +33(0)6 08 17 67 73

   

   

   

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