16/02/2021

PhD in Civil Engineering, Ceramic Materials Science or Cement Chemistry

This job offer has expired


  • ORGANISATION/COMPANY
    Centrale Lille Institut
  • RESEARCH FIELD
    EngineeringChemical engineering
    EngineeringCivil engineering
    EngineeringMaterials engineering
  • RESEARCHER PROFILE
    First Stage Researcher (R1)
  • APPLICATION DEADLINE
    31/03/2021 23:00 - Europe/Brussels
  • LOCATION
    France › Villeneuve d'Ascq
  • TYPE OF CONTRACT
    Temporary
  • JOB STATUS
    Full-time
  • HOURS PER WEEK
    35
  • OFFER STARTING DATE
    06/09/2021
  • EU RESEARCH FRAMEWORK PROGRAMME
    H2020
  • REFERENCE NUMBER
    945098

OFFER DESCRIPTION

PhD proposal: Durability of cement matrices for the conditioning of liquid organic waste under drying and carbonation

Supervision: Prof. Catherine Davy, V. Baroghel-Bouny, D. Lambertin

 

This PhD is funded by the H2020 European Union research program, and particularly through the PREDIS project: https://predis-h2020.eu/. This highly fertile context enables international exchanges, training and collaborative research, on a highly relevant subject for our society, namely the safe management of liquid organic radioactive waste from the nuclear industry, one of the main providers of electrical power.

The PhD project usesnon radioactiveReference Liquid Organic Waste (RLOW) as simulants of actual nuclear waste. These may originate from varied activities related to nuclear power plant activities, e.g. oils used for pump or gearbox lubrication, etc. They are currently stored in temporary containers, which may leak on the long term, hence the need for safe, reliable and durableconditioning solutions.

Alkali-activated materials (AAM) and in particular geopolymers, have proven effective for the encapsulation of organic liquids, potentially with the addition of surfactants to ensure their adequate immobilization.As recalled by Sun et al. 2019, the durabilityof geopolymers (GP) and more generally of alkali-activated cements (AAC) relates to the interactions between the material and its environment, which is strongly dependent on the physico-chemistry of the AAC.The current literature is relatively limitedregarding mixes between AAC and organic liquids, allowing significant knowledge and innovative information to be gathered through the project.

 

Proposed approach:

In order to progress in the characterization and the understanding of conditioning matrices, two complementary approaches will be developed. Systematic comparison with traditional Portland-cement based materials is performed throughout the research.

The first approach is related to standard, well-defined, technical tests aimed at checking the durability of the composites under standard experimental conditions, for different local raw materials or LOW or more peculiar environments. This will imply a thorough analysis of the mix parameters providing satisfactory properties, both in the fresh state (spread, absence of bleeding, hardening duration) and in the hardened state (mainly homogeneity of the composites, short term mechanical performance in uniaxial tension and compression). The raw materials (AAM and LOW) will be selected in agreement with the project international partners, for benchmarking purposes.

Complementarily, the second approach will be more fundamental, aimed at the understanding of the phenomena of interest (e.g. interactions between the AAC/RLOW composite and a particular environment) while reproducing the practical environmental conditions encountered by the waste, during the different phases leading to its storage. For this, three different conditions are considered (see below).In all these cases, durability is characterized in the hardened state by performance indicators from [Baroghel-Bouny, 2004] (i.e. porosity, pore and RLOW structure by 3D X Ray micro-tomography, fluid transport, mechanical performance, dimensional stability) and by determining the solid phase stability of the composites (by XRD, MAS NMR and leaching experiments). Leaching is assessed after a given curing duration followed by water immersion for a given duration (up to 90 days).

 

1- Study of the durability of conditioning matrix in endogenous conditions

This section investigates the AAC/RLOW composite alone, when considered in endogenous conditions, i.e. without any interaction with its surroundings (environment), over short to long term durations (up to three to four years). It is the so-called reference state.

2- Study of conditioning matrix in aerated conditions

Carbonation is promoted by partial drying of AAC. This phenomenon induces material shrinkage. For AAC, the extent of drying shrinkage highly depends on the cement chemistry. It is higher for low calcium AAC, for which water is not physically bound to the cement. Autogenous (i.e. self-desiccation) shrinkage is also observed for AAC, either due to the formation of calcium aluminate and silicate hydrates (C-A-S-H), or to the high ionic strength of the pore solution; this reduces water activity and, hence, relative humidity below 100%. A number of studies proposes mitigation strategies, e.g. addition of sand, release of reactive alumina, or surface coating of the hardened AAC. The latter is not efficient to limit autogenous shrinkage.

To our knowledge, in presence of organic liquids in the fresh AAC, the carbonation and drying shrinkage processes have not been studied yet. As the addition of organic liquids is expected to change the AAC behavior (particularly its porewater interfacial tension, its setting conditions and pore structure), these coupled processes are key aspects to investigate in this project, in relation to carbonation and shrinkage. One of the key aspects of the project will be to distinguish drying and carbonation effects.

 

3- Study of conditioning matrix durability in acid and alkaline liquid leaching

After manufacturing of the AAC/RLOW composites, several phases will lead to their storage, including temporary deposit in ambient air, and finally medium to long term sub-surface or underground storage. The latter is expected to occur in liquid-saturated environments, e.g. underground seepage water, which mineral composition may vary, with a pH ranging from acidic to highly alkaline. As indicated in [Shi et al. 2019], a number of liquid environments has been investigated for AAC, including high sulfate waters, sulfuric or organic acids, distilled water, and alkaline water typical of high strength Portland concretes. Only the latter relates to AAC/organic oil resistance to a liquid environment, and suggests some precautionary measures to take in the AAC mix-design, in order to ensure material stability over time. In most liquid environment cases however, where expansive processes may be expected (e.g. alkali-silica reactions), research is required for AAC/RLOW composites. Currently, for AAC alone, when adequately formulated, a general good resistance to a number of aggressive liquids is shown.

This part will be tackled provided that the first approach and Parts 1 and 2 of the second approach (see above) have sufficiently progressed.

 

Practical conditions:

Monthly salary: 1700€ net amount without project travel, training or collaboration exchange fees.

The PhD candidate will be provided with a dedicated office space, a personal laptop, andfull access to experimental and numerical equipments at Centrale LilleInstitut. Regular meetings will be set upwith the supervising team (at least once a week), opportunities to present his/her research to the industrial and academic project partners in the framework of dedicated meetings or international conferences, and to publish in international peer-reviewed journals (e.g. Journal of the American Ceramic Society, Cement and Concrete Research, Materials Letters).

 

References:

Baroghel-Bouny, Scientific and technical documents of AFGC (AFGC), Paris, France, 240 p., 2004

Bernal and Provis, J Am Ceram Soc ,97(4) 997-1008, 2014

Cantarel et al. Ceram Int (44) 10558-10568, 2018

Davy et al. J Am Ceram Soc (102) 949-954, 2019

Kani et al. Cem Con Comp (34) 25-33, 2012

Kuenzel et al. Con Build Mat (66) 442-446, 2014

Marchon et al. Soft Matter (9) 10719-10728, 2013

Medpelli et al. J Am Ceram Soc (97)1 70-73, 2014

Seo et al. U.S. Patent No. US20130055924 A1, 2013

Sun and Vollpracht, Cem Con Comp, 95 98-110, 2019

Shi et al. Cem Con Res. (122) 227-250, 2019

Tavor et al. IndEngChem Res (46) 6801-6805, 2007

Xue et al. Cem Con Comp, (94) 43-52, 2018

More Information

Benefits

Opportunity to develop research in a joint-supervision team and in contact with 47 European partners

Centrale Lille Institut is ideally located in Europe (crossroads between Northern and Southern Europe, 30mins train from Brussels, 1h train from Paris)

Eligibility criteria

Hold a MSc in Engineering Sciences and/or a French Engineering School Diploma

Fluency in English will be highly appreciated

Selection process

Includes CV+motivation letter, several oral interviews via visio-conference by the different involved partners (in French or in English), and provision of any necessary written document in French or in English

Offer Requirements

  • REQUIRED EDUCATION LEVEL
    Engineering: Master Degree or equivalent
    Chemistry: Master Degree or equivalent
  • REQUIRED LANGUAGES
    FRENCH: Good

Skills/Qualifications

The candidate needs to:

- have excellent oral and writing abilities, in English and if possible in French too. This will be assessed during the recruitment process.

- be very keen on developing experimental research in a joint team between the main supervisor (Prof. Catherine Davy at Centrale Lille Institut) and the co-supervisors (Université Gustave Eiffel - IFSTTAR and CEA Marcoule)

- have skills, rigor and precision in the characterization of cement based materials (amorphous materials preferably), and/or organics, and more generally in the characterization of the structure of porous materials

- be willing to travel during the project, which involves 48 partners (opportunities for traineeships outside the main host in Lille will be offered)

- be passionate and willing to contribute to improving the storage solutions of European nuclear radioactive waste

Specific Requirements

- have excellent oral and writing abilities, in English and if possible in French too. This will be assessed during the recruitment process.

- have skills, rigor and precision in the characterization of cement based materials (amorphous materials preferably), and/or organics, and more generally in the characterization of the structure of porous materials

- be passionate and willing to contribute to improving the storage solutions of European nuclear radioactive waste

Work location(s)
1 position(s) available at
Centrale Lille Institut
France
Hauts de France
Villeneuve d'Ascq
F-59651
Cité Scientifique, CS20048

EURAXESS offer ID: 605990

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