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Co-valorisation de sédiments et de sols fins par apport de liants et de fibres

Abstract : In order to improve the management and treatment of dredged marine sediments and quarry fillers as solid wastes, a research thesis work has been conducted on the solidification/stabilization (S/S) of sediments and fillers with binders and other additives. The focused beneficial use consists in a road sub layer material. So composite materials are implemented with different binders: hydraulic and pozzolanic binders (cement, lime, fly ash and silica fume). A stabilization by an admixture of a chemical product has been also tested. An innovative mixture has been performed with natural and geosynthetic fibers in a cement-sediment or filler matrix. A mechanical and durability behavior analysis was made for these various mixtures. A representative selection of French coast sediments is first proposed. A basic characterization of the selected fine materials has consisted in physical and chemical properties (grain size distribution, Atterberg limits, organic matter and carbonate contents). The different mixture components are presented in details: binders and others. A complete experimental program is given with the parameters considered. Protocols for preparation, conservation and testing are presented. Mechanical testing has been performed on all mixture samples. Unconfined compressive strength -UCS-, indirect tensile test (Brazilian test) and wetting/drying tests have been undertaken to evaluate the mechanical performances through different mixtures. The analyses of all the results have pointed out the influences of each additive in the mixture in respect with a UCS threshold value of 1MPa to be reached. Influences are mainly discussed with the mixture parameters (dosages, time conservation) and sediments or filler properties. Moreover, the organic matter and carbonate contents of the sediments influence the UCS resistance, but the lime can inhibit the organic matter action. Comparisons are made between all the mixtures so as to improve the mechanical resistance (i) a sand corrector (0/2mm and 0/5mm) to reinforce the fine material skeleton is proposed, (ii) a chemical product is tested with addition of silicate sand, (iii) an innovative improvement by addition of fibers to reinforce the cement-sediment matrix is developed. This novel type of composite material including cement-sediment-fibers has been undertaken through a specific experimental program. Natural (flax) and artificial (polypropylene and polyacrylonitrile) fibers have been added in a cement-sediment matrix according to the different fiber types with various lengths and different dosages. The replacement level of cement is of 7%, considered as an economical one. All results are discussed so as to propose an optimal formulation with the fibers used. Finally, considering the economical chosen dosages for binders and for all mixtures tested, a road sub layer material classification based on the use of Young Modulus and tensile strength resistance is presented. A possible application for the different mixtures tested in a road sub layer has been observed. All the results concern the classes S1 to S5 proposed in the GTR french recommendations. The addition of fibers in a cement based S/S process for marine fine sediments and quarry fillers has been demonstrated. Consequently, the idea of adding a content of fibers as solid wastes to valorize marine fines sediment and quarry fillers as construction material is feasible.
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https://tel.archives-ouvertes.fr/tel-00731611
Contributor : Valérie Casado-Malaizé <>
Submitted on : Thursday, September 13, 2012 - 10:34:21 AM
Last modification on : Monday, April 27, 2020 - 4:26:29 PM

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  • HAL Id : tel-00731611, version 1

Citation

Y. Liang. Co-valorisation de sédiments et de sols fins par apport de liants et de fibres. Interfaces continentales, environnement. Université de Caen, 2012. Français. ⟨tel-00731611⟩

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