Valorisation du laitier LD de Dunkerque dans les liants hydrauliques routiers

Ce travail de thèse a porté sur la valorisation du laitier LD de Dunkerque dans les Liants Hydrauliques Routiers (LHR), en particuliers dans le Sidmix(r) qui est un LHR développé par la société S.G.A. Le plan de cette étude s'est orienté dans trois directions. Dans un premier temps, une caractérisation physico-chimique et minéralogique approfondie d'un laitier LD classique a été effectuée dans le but de mettre en place des outils de caractérisation adaptés à l'ensemble des laitiers LD. Ensuite, nous avons fait une étude de variabilité des laitiers LD produits sur le site afin de connaître l'effet de leurs compositions minéralogiques et de leurs réactivités sur le comportement mécanique du Sidmix(r) dans l'objectif de sélectionner les meilleurs laitiers pour optimiser les performances de ce dernier. Enfin, nous avons cherché à modifier le process industriel en intervenant sur le laitier LD en fusion pour en faire un liant hydraulique à part entière.This work has carried out on the reuse of LD slag in Hydraulic Road Binders (HRB) in particularly in the Sidmix(r) that is a HRB developed by S.G.A. This work is divided in three parts. In the first one, the characterization (physical, chemical and mineralogical) of a classical LD slag has been carried out in order to implement methods for a characterization suitable to all LD slag. The second part developed in this work is a variability study of LD slag produced in Dunkerque to determine the influence of the mineralogical properties and the reactivity of LD slag on the behavior of Sidmix(r). The purpose, in this case, is to propose a method of selection of LD slag to obtain optimized performances of this HRB. Finally, the third part developed in this work is a modification of mineralogical and chemical properties of LD slag to transform this material into a hydraulic binder by thermal process

Mineralogical Transformations During a Stabilization Process Developed for the Valorization of Municipal Solid Waste Incineration (MSWI) Fly Ash

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Valorisation du laitier LD de Dunkerque dans les liants hydrauliques routiers

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Utilization of sludge from ready-mixed concrete plants as a substitute for limestone fillers

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Classification of Recycled Aggregates Using Deep Learning

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Determination of the composition of recycled aggregates using a deep learning-based image analysis

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Biomineralization of calcium carbonate by marine bacterial strains isolated from calcareous deposits

Biomineralization induced by microbial enzymes, which catalyse CaCO3 precipitation, is a promising field of research for various applications in building eco-materials. Especially, this could provide an eco-friendly process for protection of coastal areas against erosion. In the present investigation, fourteen bacterial strains were isolated and characterized from both natural seawater and calcareous deposits formed on a cathodically protected steel mesh in marine environment. All of them induced calcium carbonate precipitation in various media by producing urease and/or carbonic anhydrase enzymes. The calcium carbonate minerals produced by bacteria were identified by microscopy and µ-Raman spectroscopy. In parallel, an experimental set-up, based on a column reactor, was developed to study biomineralization and microbial capacity of Sporosarcina pasteurii to form sandy agglomerate. These well-known calcifying bacteria degraded the urea present in liquid medium circulating through the column to produce calcium carbonate, which acted as cement between sand particles. The bio-bricks obtained after 3 weeks had a compressive strength of 4.2 MPa. 20% of the inter-granular voids were filled by calcite and corresponded to 13% of the total mass. We successfully showed that bio-column system can be used to evaluate the bacterial ability to agglomerate a sandy matrix with CaCO3

Reactivity of Recycled Aggregates Used for Pavement Base: From Field to Laboratory

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New Biocalcifying Marine Bacterial Strains Isolated from Calcareous Deposits and Immediate Surroundings

International audienceMarine bacterial biomineralisation by CaCO 3 precipitation provides natural limestone structures, like beachrocks and stromatolites. Calcareous deposits can also be abiotically formed in seawater at the surface of steel grids under cathodic polarisation. In this work, we showed that this mineral-rich alkaline environment harbours bacteria belonging to different genera able to induce CaCO 3 precipitation. We previously isolated 14 biocalcifying marine bacteria from electrochemically formed calcareous deposits and their immediate environment. By microscopy and µ-Raman spectroscopy, these bacterial strains were shown to produce calcite-type CaCO 3. Identification by 16S rDNA sequencing provided between 98.5 and 100% identity with genera Pseudoalteromonas, Pseudidiomarina, Epibacterium, Virgibacillus, Planococcus, and Bhargavaea. All 14 strains produced carbonic anhydrase, and six were urease positive. Both proteins are major enzymes involved in the biocalcification process. However, this does not preclude that one or more other metabolisms could also be involved in the process. In the presence of urea, Virgibacillus halodenitrificans CD6 exhibited the most efficient precipitation of CaCO 3. However, the urease pathway has the disadvantage of producing ammonia, a toxic molecule. We showed herein that different marine bacteria could induce CaCO 3 precipitation without urea. These bacteria could then be used for eco-friendly applications, e.g., the formation of bio-cements to strengthen dikes and delay coastal erosion

The FastCarb project: Taking advantage of the accelerated carbonation of recycled concrete aggregates

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