Ifsttar PhD subject

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Detailed form :

Title : Ecodesign of a sustainable and cost-effective reinforced geopolymer over the life cycle of a structure

Main host Laboratory - Referent Advisor MAST - FM2D  -  DJERBI Assia      tél. : +33 181668376

Director of the main host Laboratory FEN-CHONG Teddy  -

PhD Speciality Matériaux et structures - génie civil

Axis of the performance contract 2 - COP2017 - More efficient and resilient infrastructure

Main location Marne-la-Vallée

Doctoral affiliation UNIVERSITE PARIS-EST

PhD school SCIENCES, INGENIERIE ET ENVIRONNEMENT (SIE)

Planned PhD supervisor FEN-CHONG Teddy  -  Université Gustave Eiffel  -  MCD

Planned financing Contrat doctoral  - Ifsttar

Abstract

Context :
Current practice in the design of civil engineering structures is strongly oriented by the construction phase. Traditionally, the design of structures consists in selecting a dimensioning (choice of material and construction provisions) that makes it possible to achieve the lowest possible initial construction cost while respecting the prescribed requirements for a given service/life span. This approach is now being revisited to seek to integrate the entire life cycle of the structure, i.e. to consider all stages of its life, from design to the end of its service life. Indeed, activities related to the life cycle of the structure during the operating (maintenance/rehabilitation) and end-of-life phases generate much greater economic, environmental and societal impacts than the simple design/construction phase.

Research on durability, although limited, has shown that alkali-activated materials in general and geopolymers in particular have remarkable chemical stability[Lecomte et al., 2006, Idir et al., 2012, Idir et al., 2019]. Indeed, under CO2-rich conditions, geopolymers have better "anti-corrosion" properties than Portland cement-based binders. This is due in particular to the three-dimensional structure of the network formed in geopolymeric gels and also to the absence or low Ca(OH)2 content. Zhu et al., 2010] have shown that, on the one hand, geopolymers used in oil wells carbonate more slowly than petroleum cement grouts, and on the other hand, carbonation changes pore size in geopolymers very slightly.

The objective of using reinforced geopolymers as an alternative to traditional reinforced concrete is to influence performance during the various phases of the structure's life. Geopolymers can contribute to increasing durability, reducing the frequency of maintenance operations or the quantities of materials used in the construction and maintenance of the structure. This material, although promising from a performance point of view (particularly with regard to the initiation of corrosion), is still a possibility that has not been considered in the design of the structures, as it is evaluated in the context of an analysis restricted to the initial cost alone.

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Objectives of the thesis:
This thesis proposes an innovative methodological approach to analyze the relevance of armed geopolymers in their life cycle according to three criteria that can represent conflicting issues: economic, environmental and performance. This approach consists of a multi-criteria analysis to evaluate all design variants, integrating architectural considerations in particular, and to provide a global vision that helps project owners and managers in their decision-making.

The performance of the material will be tested for the durability of the coating thickness to limit the risk of reinforcement corrosion caused by chloride ions[Djerbi et al., 2013]. This will be done on the basis of a functional unit involving a reinforced geopolymer and reinforced concrete. In parallel with this study of the durability of geopolymer material, a cost and environmental analysis[Gervásio et al. 2015, Orcesi et al. 2018] will be considered to discriminate between the different material choice and design strategies from the construction stage, taking into account the entire life cycle (see theses supervised by R. Idir).

The challenge of the thesis is therefore to conduct a multi-criteria analysis at the different stages of a functional unit of structure, or even a complete structure, to identify if a reinforced geopolymer solution, although more expensive during the construction phase, can become advantageous over the entire life cycle of the structure.

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References:
• Cyr M., R. Idir, T. Poinot (2012). Properties of inorganic polymer (geopolymer) mortars made of glass cullet, Journal of Materials Science, March 2012, Volume 47, Issue 6, pp 2782–2797.
• Djerbi A, S. Bonnet, A. Khelidj, V. Baroghel-Bouny (2013). Effect of uniaxial compressive loading on gas permeability and chloride diffusion coefficient of concrete and their relationship. Cement and Concrete Research, 2013, 52, 131-139.
• Gervásio H., Simões da Silva, L., Perdigão, V. Orcesi, A.D. & Andersen, R. (2015). Influence of maintenance strategies on the life cycle performance of composite highway bridges, Structural Engineering International, 25(2), 184-196.
• Idir R., M. Cyr., A. Pavoine. Investigations on the durability of geopolymer made of recycled glass, publication soumise à construction and Building Materials. CONBUILDMAT-D-19-01571R1-1.
• Lecomte C. Henrist, M. Liégeois, F. Maseri, A. Rulmont, R. Cloots (2006). (Micro)-structural comparison between geopolymers, alkali-activated slag cement and Portland cement. Journal of the European Ceramic Society.
• Orcesi A.D., Cremona, C. & Ta, N.-B. (2018). Optimization of design and life-cycle management for steel-concrete composite bridges, Structural engineering international, 28, 2, International Association for Bridge and Structural Engineering - IABSE, pp 185-195, DOI: 10.1080/10168664.2018.1453763.
• Zhu H., Yao X., Zhang Z. (2010). Study on non-cement based alkali-activated material for oil and gas well cementing at low and moderate temperatures, C. Shi, X. Shen (Eds.), The First International Conference on Advances in Chemically-activated Materials (CAM'2010), Jinan, Shandong, China, RILEM Publication S.A.R.L, 100–106.

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Current PhD theses (all started in 2017) related to the subject:
• Développement, caractérisation et durabilité de géopolymères à faible impact CO2 à base de poudre de verre ; thèse co-encadrée par Rachida Idir (CEREMA) et Martin Cyr (LMDC/Université de Toulouse).
• Valorisation de ressources naturelles et sous-produits locaux pour la fabrication d'éco-matériaux durables ; thèse co-encadrée par Rachida Idir (CEREMA) et Martin Cyr (LMDC/Université de Toulouse) + cotutelle avec l’ITC du Cambodge.
• Durabilité d’un liant géopolymérique à faible impact environnemental ; thèse de Baptiste Luzu co-dirigée par T. FEN-CHONG (IFSTTAR) et L. GAUTRON (UPEM), encadrée par A. DJERBI (MAST/FM²D) et M. DUC (GERS/SRO).

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Expected results and valorisation:
• 3 publications in international scientific journals
• Supply of a database comparing hydraulic concretes and geopolymeric concretes
• Introduction of this type of binder and implementation rules in the formulation of new concretes in EN206/CN
• Creation of an industrial valorization chain for geopolymeric concretes
• Other valuations in the form of communications (conferences, congresses, etc.).

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Expected profile:
The candidate must be expected to have very strong skills in:
• Physico-chemistry of construction materials
• Sustainable Construction.
The candidate must have a strong interest in experimental research (including metrology) and must demonstrate relational skills that allow him/her to work in a team.
Knowledge of Life Cycle Assessment would be valuable.

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Supervision:
The work will be supervised by Teddy Fen-Chong (Sustainable Development Research Director, Ifsttar), Assia Djerbi (Sustainable Development Research Scientist, Ifsttar), and Rachida Idir (Sustainable Development Research Scientist, Cerema).
During the thesis work, the doctoral student will divide his or her time between the Cerema Eco-materials Laboratory in Sourdun, and the FM2D Laboratory of the Ifsttar MAST department in Champs-sur-Marne. These two laboratories are in Seine-et-Marne.

Keywords : Eco-design, Geopolymer, LCA, Economic analysis, Sustainability, Corrosion

Main host Laboratory - Referent Advisor	MAST - FM2D - DJERBI Assia tél. : +33 181668376
Director of the main host Laboratory	FEN-CHONG Teddy -
PhD Speciality	Matériaux et structures - génie civil
Axis of the performance contract	2 - COP2017 - More efficient and resilient infrastructure
Main location	Marne-la-Vallée
Doctoral affiliation	UNIVERSITE PARIS-EST
PhD school	SCIENCES, INGENIERIE ET ENVIRONNEMENT (SIE)
Planned PhD supervisor	FEN-CHONG Teddy - Université Gustave Eiffel - MCD
Planned financing	Contrat doctoral - Ifsttar
Abstract Context : Current practice in the design of civil engineering structures is strongly oriented by the construction phase. Traditionally, the design of structures consists in selecting a dimensioning (choice of material and construction provisions) that makes it possible to achieve the lowest possible initial construction cost while respecting the prescribed requirements for a given service/life span. This approach is now being revisited to seek to integrate the entire life cycle of the structure, i.e. to consider all stages of its life, from design to the end of its service life. Indeed, activities related to the life cycle of the structure during the operating (maintenance/rehabilitation) and end-of-life phases generate much greater economic, environmental and societal impacts than the simple design/construction phase. Research on durability, although limited, has shown that alkali-activated materials in general and geopolymers in particular have remarkable chemical stability[Lecomte et al., 2006, Idir et al., 2012, Idir et al., 2019]. Indeed, under CO2-rich conditions, geopolymers have better "anti-corrosion" properties than Portland cement-based binders. This is due in particular to the three-dimensional structure of the network formed in geopolymeric gels and also to the absence or low Ca(OH)2 content. Zhu et al., 2010] have shown that, on the one hand, geopolymers used in oil wells carbonate more slowly than petroleum cement grouts, and on the other hand, carbonation changes pore size in geopolymers very slightly. The objective of using reinforced geopolymers as an alternative to traditional reinforced concrete is to influence performance during the various phases of the structure's life. Geopolymers can contribute to increasing durability, reducing the frequency of maintenance operations or the quantities of materials used in the construction and maintenance of the structure. This material, although promising from a performance point of view (particularly with regard to the initiation of corrosion), is still a possibility that has not been considered in the design of the structures, as it is evaluated in the context of an analysis restricted to the initial cost alone. --------------------------- Objectives of the thesis: This thesis proposes an innovative methodological approach to analyze the relevance of armed geopolymers in their life cycle according to three criteria that can represent conflicting issues: economic, environmental and performance. This approach consists of a multi-criteria analysis to evaluate all design variants, integrating architectural considerations in particular, and to provide a global vision that helps project owners and managers in their decision-making. The performance of the material will be tested for the durability of the coating thickness to limit the risk of reinforcement corrosion caused by chloride ions[Djerbi et al., 2013]. This will be done on the basis of a functional unit involving a reinforced geopolymer and reinforced concrete. In parallel with this study of the durability of geopolymer material, a cost and environmental analysis[Gervásio et al. 2015, Orcesi et al. 2018] will be considered to discriminate between the different material choice and design strategies from the construction stage, taking into account the entire life cycle (see theses supervised by R. Idir). The challenge of the thesis is therefore to conduct a multi-criteria analysis at the different stages of a functional unit of structure, or even a complete structure, to identify if a reinforced geopolymer solution, although more expensive during the construction phase, can become advantageous over the entire life cycle of the structure. --------------------------- References: • Cyr M., R. Idir, T. Poinot (2012). Properties of inorganic polymer (geopolymer) mortars made of glass cullet, Journal of Materials Science, March 2012, Volume 47, Issue 6, pp 2782–2797. • Djerbi A, S. Bonnet, A. Khelidj, V. Baroghel-Bouny (2013). Effect of uniaxial compressive loading on gas permeability and chloride diffusion coefficient of concrete and their relationship. Cement and Concrete Research, 2013, 52, 131-139. • Gervásio H., Simões da Silva, L., Perdigão, V. Orcesi, A.D. & Andersen, R. (2015). Influence of maintenance strategies on the life cycle performance of composite highway bridges, Structural Engineering International, 25(2), 184-196. • Idir R., M. Cyr., A. Pavoine. Investigations on the durability of geopolymer made of recycled glass, publication soumise à construction and Building Materials. CONBUILDMAT-D-19-01571R1-1. • Lecomte C. Henrist, M. Liégeois, F. Maseri, A. Rulmont, R. Cloots (2006). (Micro)-structural comparison between geopolymers, alkali-activated slag cement and Portland cement. Journal of the European Ceramic Society. • Orcesi A.D., Cremona, C. & Ta, N.-B. (2018). Optimization of design and life-cycle management for steel-concrete composite bridges, Structural engineering international, 28, 2, International Association for Bridge and Structural Engineering - IABSE, pp 185-195, DOI: 10.1080/10168664.2018.1453763. • Zhu H., Yao X., Zhang Z. (2010). Study on non-cement based alkali-activated material for oil and gas well cementing at low and moderate temperatures, C. Shi, X. Shen (Eds.), The First International Conference on Advances in Chemically-activated Materials (CAM'2010), Jinan, Shandong, China, RILEM Publication S.A.R.L, 100–106. --------------------------- Current PhD theses (all started in 2017) related to the subject: • Développement, caractérisation et durabilité de géopolymères à faible impact CO2 à base de poudre de verre ; thèse co-encadrée par Rachida Idir (CEREMA) et Martin Cyr (LMDC/Université de Toulouse). • Valorisation de ressources naturelles et sous-produits locaux pour la fabrication d'éco-matériaux durables ; thèse co-encadrée par Rachida Idir (CEREMA) et Martin Cyr (LMDC/Université de Toulouse) + cotutelle avec l’ITC du Cambodge. • Durabilité d’un liant géopolymérique à faible impact environnemental ; thèse de Baptiste Luzu co-dirigée par T. FEN-CHONG (IFSTTAR) et L. GAUTRON (UPEM), encadrée par A. DJERBI (MAST/FM²D) et M. DUC (GERS/SRO). --------------------------- Expected results and valorisation: • 3 publications in international scientific journals • Supply of a database comparing hydraulic concretes and geopolymeric concretes • Introduction of this type of binder and implementation rules in the formulation of new concretes in EN206/CN • Creation of an industrial valorization chain for geopolymeric concretes • Other valuations in the form of communications (conferences, congresses, etc.). --------------------------- Expected profile: The candidate must be expected to have very strong skills in: • Physico-chemistry of construction materials • Sustainable Construction. The candidate must have a strong interest in experimental research (including metrology) and must demonstrate relational skills that allow him/her to work in a team. Knowledge of Life Cycle Assessment would be valuable. --------------------------- Supervision: The work will be supervised by Teddy Fen-Chong (Sustainable Development Research Director, Ifsttar), Assia Djerbi (Sustainable Development Research Scientist, Ifsttar), and Rachida Idir (Sustainable Development Research Scientist, Cerema). During the thesis work, the doctoral student will divide his or her time between the Cerema Eco-materials Laboratory in Sourdun, and the FM2D Laboratory of the Ifsttar MAST department in Champs-sur-Marne. These two laboratories are in Seine-et-Marne.
Keywords :	Eco-design, Geopolymer, LCA, Economic analysis, Sustainability, Corrosion

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