Multiskalige Modellierung von nanoverstärkten Geopolymer/CNTs-Materialien
Zusammenfassung der Projektergebnisse
Nowadays, geopolymers are advanced alternatives to cementitious materials whose production is accompanied by much lower CO2 emissions than Portland cement. Geopolymers make possible to use industrial wastes while transforming them into a new binding material. Reinforcing geopolymers with nanoparticles such as carbon nanotubes would considerably improve their microstructure, mechanical performance and their long-term durability. The objective of this project is to develop a multi-scale modelling approach to understand the mechanical and structural properties of geopolymers reinforced with carbon nanotubes. For this, numerical modelling and simulation tools are used such as molecular dynamics and also Coarse-Grained Monte Carlo method in order to understand the link between the different scales. Multiple factors are considered such as water content, heating, chemical composition, porosity and dosage of nanoparticles. The project will have a great impact on the development of future ecological building materials with low CO2 production. Modelling at the atomic scale has enabled the analysis of complex structures of geopolymers including carbon nanotubes. This technique showed the important role of the stability of the interface on the mechanical performance of the nanostructure. On the other hand, a model was established to take into account porosity and pore size to predict good thermal and acoustic insulation of geopolymers. This method also allowed the analysis of the thermal stability and the fragile/ductile nature of nano-reinforced geopolymer samples at very high temperatures up to 1327°C. Calculations based on density functional theory and molecular dynamics methods showed the interaction mechanisms and adsorption energies between graphenebased nanosheets and primary aqueous geopolymer species. The role of a nano-coating with a layer of graphene in improving the waterproofing of geopolymer surfaces was subsequently shown. Furthermore, the models established by the “Coarse Grained Monte Carlo” method analyzed the condensation/hydrolysis reactions of aluminosilicates with carbon nanotubes. The atomic-scale modeling studies show that incorporating a low concentration of doped carbon nanotubes (1.08%) would increase the elastic modulus by 165%. The reinforced nanostructure has proven to be stable and resistant to temperatures up to 1327°C. It is difficult to deform along the (001) plane up to 1127°C. Its ductility doubles at room temperature and heating improves the rigidity of its structure. Experimental measurements show that the addition of 0.5% carbon nanotubes improves flexural strength and reduces crack formation. The perspective of the project would be to use these multi-scale modeling tools to study the improvement of the electrical and piezoelectric performances of geopolymer binders thanks to multifunctional modifications of carbon nanotubes. A clear understanding of the link between structure-property mechanisms needs to be achieved. New properties could be revealed with potential integration for electrical energy storage in these materials. The methodology of analysing the complex structure of nano-enhanced geopolymers from the atomistic to the macroscopic scale has yielded very promising results reported in a series of international peer-reviewed publications. The LGCgE laboratory at the University of Lille has had great success in atomistic modelling results on the mechanical reinforcement and durability of geopolymers. German partner TUDa has established new scaling models for condensation/hydrolysis reactions of aluminosilicates and their interactions with carbon nanoparticles. The experimental measurements were carried out on samples of nanoreinforced geopolymers to evaluate their microstructural and mechanical properties. Besides, Multiphase particles for the percolation and electrical conductivity model has been studied on geopolymer-graphite composite.
Projektbezogene Publikationen (Auswahl)
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High strength metakaolin-based geopolymer reinforced by pristine and covalent functionalized carbon nanotubes. Construction and Building Materials, 327, 126910.
Sekkal, W. & Zaoui, A.
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3D Off-Lattice Coarse-Grained Monte Carlo Simulations for Nucleation of Alkaline Aluminosilicate Gels. Materials, 16(5), 1863.
Izadifar, Mohammadreza; Valencia, Nicolas Castrillon; Xiao, Peng; Ukrainczyk, Neven & Koenders, Eduardus
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Coarse-Grained Monte Carlo Simulations with Octree Cells for Geopolymer Nucleation at Different pH Values. Materials, 17(1), 95.
Valencia, Nicolas Castrillon; Izadifar, Mohammadreza; Ukrainczyk, Neven & Koenders, Eduardus
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Effect of Carbon Nanomaterials on the Microstructural and Mechanical Properties of Geopolymer Binders. RILEM Bookseries, 540-550. Springer Nature Switzerland.
Dubyey, Liliya; Winn, Leon; Ukrainczyk, Neven & Koenders, Eduardus
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Nanoscale modeling of advanced sustainable graphene nanocoated geopolymer materials, IGES 2023
A. Zaoui
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Silicate Dissolution Mechanism from Metakaolinite Using Density Functional Theory. Nanomaterials, 13(7), 1196.
Izadifar, Mohammadreza; Ukrainczyk, Neven & Koenders, Eduardus
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Theoretical investigation of protective graphene-coated metakaolin geopolymer interface under moisture and chemical composition effects. Powder Technology, 430, 119007.
Sekkal, W.; Izadifar, M.; Zaoui, A.; Ukrainczyk, N. & Koenders, E.
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Theoretical Studies of Adsorption Reactions of Aluminosilicate Aqueous Species on Graphene-Based Nanomaterials: Implications for Geopolymer Binders. ACS Applied Nano Materials, 6(18), 16318-16331.
Izadifar, Mohammadreza; Sekkal, Wassila; Dubyey, Liliya; Ukrainczyk, Neven; Zaoui, Ali & Koenders, Eduardus
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Thermal and acoustic insulation properties in nanoporous geopolymer nanocomposite. Cement and Concrete Composites, 138, 104955.
Sekkal, W. & Zaoui, A.
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Electrical conductivity of geopolymer-graphite composites: Percolation, mesostructure and analytical modeling. Construction and Building Materials, 411, 134536.
Zhang, Shifan; Ukrainczyk, Neven; Zaoui, Ali & Koenders, Eddie
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Residual water and interfacial bonding effects on the mechanical performance of CNT/fly ash geopolymer binder. Structural Concrete, 25(5), 3648-3661.
Sekkal, W. & Zaoui, A.
