Geopolymer mortar with flash-calcined dredged sediment

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Experimental study on the reuse of a dredging sludge from west of Algeria in brick fabrication

The siltation as a natural phenomenon threatens the performance of harbors by reducing their docking volume compared to dams in terms of water storage, as well as their life span. An alarming rate of siltation is noted in the various basins requires an urgent cleaning operations. In a context of valorization of the sludge resulted from the dredging operations of the basins of the Oran’s port and those of the Bouhanifia’s dam which are  located in Western Algeria, it is a question of studying possibilities which are offered by the use of these vases in the design of bricks building. The followed methodology is based on a physicochemical and mineralogical characterization of the two vases to reveal the one closest to the standards recommended for the manufacture of the baked brick. After analyzing sediments dredged in the port of Oran, it turned out that there is a dominance of sandy sediments, which are not recoverable in the areas of bricks we have targeted. Sustainability tests were performed on several sludge dam samples at different temperatures and percentages of water. The results gave a satisfaction in mechanical strength and durability for a firing temperature of 850 ° C and a percentage of water of 20%

Experimental study on the reuse of a dredging sludge from west of Algeria in brick fabrication

The siltation as a natural phenomenon threatens the performance of harbors by reducing their docking volume compared to dams in terms of water storage, as well as their life span. An alarming rate of siltation is noted in the various basins requires an urgent cleaning operations. In a context of valorization of the sludge resulted from the dredging operations of the basins of the Oran’s port and those of the Bouhanifia’s dam which are  located in Western Algeria, it is a question of studying possibilities which are offered by the use of these vases in the design of bricks building. The followed methodology is based on a physicochemical and mineralogical characterization of the two vases to reveal the one closest to the standards recommended for the manufacture of the baked brick. After analyzing sediments dredged in the port of Oran, it turned out that there is a dominance of sandy sediments, which are not recoverable in the areas of bricks we have targeted. Sustainability tests were performed on several sludge dam samples at different temperatures and percentages of water. The results gave a satisfaction in mechanical strength and durability for a firing temperature of 850 ° C and a percentage of water of 20%

Self-compacting Backfills using Fly Ash and Dredged Marine Sediments for Public Work Applications

Sediment accumulation at the bottom of ports disrupts maritime activities and disturbs the physicochemical balance of water bodies. In France, the maintenance of the 6500-kilometer long coastline would require the extraction of about 50 million m3 of marine sediments every year. For several years, these sediments were considered waste. However, they are increasingly being acknowledged as a resource in need of management. Several research studies were conducted to find valorization ways that satisfy technical and regulatory requirements. These sediments present interesting heterogeneous physicochemical, mineralogical, and geotechnical characteristics. However, they may contain contamination, which could limit their uses. This paper deals with the possibility of producing self-compacting backfills using dredged marine sediments, fly-ash, and hydraulic binders for public work applications. The impact of dredged sediments on the composition of self-compacting backfills was studied. Moreover, the impact of fly ash and binder type and percentage on the backfill behavior and mechanical properties was discussed

Marine Dredging Sediments Valorization in Self-Compacting Concretes

Rock and eroded soil are transported by wind, tide, and human action (development works), and deposited as sediment in ports, estuaries, and rivers. The sediment accumulation at the bottom of ports disrupts maritime activities and disturbs the physicochemical balance of water bodies. As a result, dredging is necessary to reduce sediment deposits and restore the natural environment for proper port functioning. At the national level, the maintenance of the 6,500-kilometer French coastline would require the extraction of about fifty million cubic meters of marine sediment every year. These dredged sediments have been used in civil engineering applications for about ten years, in order to reduce their economic and environmental impact. The proposed study addresses the potential use of sediments to produce accropode blocks for maritime public works applications. It consists in developing concrete mixtures using dredged marine sediment treated to protect against erosion. A study of material characterization, optimization of the composition of the concrete formulation, as well as a determination of the mechanical, physical and durability properties of the concrete were necessary to validate the technical feasibility of this new solution. Around 700 small accropode blocks were then prepared to better analyze the structure stability against swell effects. The obtained results show that the sediments could not produce Self Compacting Concrete (SCC). However, sediment treatment with 6% by weight of cement has enabled the production of SCC. It is worth noting that the use of superplasticizer was essential to ensure concrete workability. Increasing the cement percentage has also improved the composite workability. Finally, a concrete compressive strength greater than 40 MPa has been achieved when using 300 kg/m3 of treated sediments

Experimental study on the reuse of a dredging sludge from west of Algeria in brick fabrication

The siltation as a natural phenomenon threatens the performance of harbors by reducing their docking volume compared to dams in terms of water storage, as well as their life span. An alarming rate of siltation is noted in the various basins requires an urgent cleaning operations. In a context of valorization of the sludge resulted from the dredging operations of the basins of the Oran’s port and those of the Bouhanifia’s dam which are  located in Western Algeria, it is a question of studying possibilities which are offered by the use of these vases in the design of bricks building. The followed methodology is based on a physicochemical and mineralogical characterization of the two vases to reveal the one closest to the standards recommended for the manufacture of the baked brick. After analyzing sediments dredged in the port of Oran, it turned out that there is a dominance of sandy sediments, which are not recoverable in the areas of bricks we have targeted. Sustainability tests were performed on several sludge dam samples at different temperatures and percentages of water. The results gave a satisfaction in mechanical strength and durability for a firing temperature of 850 ° C and a percentage of water of 20%

Fluorine soil stabilization using hydroxyapatite synthesized from minerals wastes

International audienceThe objective of this study was to present a new approach to mineral waste valorization, based on the synthesis of hydroxyapatite (HAP) as an efficient and cost-effective adsorbent for the stabilization of fluorides (F-) in soil. Hydroxyapatites were synthesized from the reaction of potassium dihydrogen phosphate (KH2PO4) and waste paper fly ash (WPFA), fine limestone clay (FLC) and limestone filler (LF) rich in calcite. X-ray diffraction characterization results showed that for HAPFLC and HAPFL the main resulting phases were brushite (CaHPO5·2H2O) and for HAPWPFA was hydroxyapatite (Ca5(PO4)3OH). The FTIR spectra showed similar patterns to natural HAP containing orthophosphate groups (PO43-), hydroxylated groups (OH–) and both types A/B of carbonate apatite. SEM-EDS analysis of the individual HAP revealed a morphology consistent with phosphocalcic hydroxyapatite crystals. EDS analysis revealed a Ca/P atomic ratio equal to 1.92, 1.85 and 1.7 for HAPFLC, HAPLF and HAPWPFA respectively, which is similar to the stoichiometry of hydroxyapatites (Ca/P = 1.67). The use of HAP as an amendment to stabilize fluorides (F-) in the soil was demonstrated to be effective, the addition of 1% of the different HAP allowed the decrease of the concentration of F in the raw soil (73.8 mg/kg) to concentrations below the IWSI threshold (10 mg/kg), to 4.68 mg/kg, 5.63 mg/kg, and 0.8 mg/kg for HAPFLC, HAPFL and HAPWPFA respectively. Fluoride (F) sequential extraction results showed that it was extracted from the residual fraction (Fraction 4) after soil treatment, and was generally trapped on the hydroxyapatites (Ca5(PO4)3(OH)) by anion exchange with the hydroxides (OH–) to form the stable and insoluble fluorapatite ((Ca5(PO4)3F). © 2023 The Author

Essais d’aptitude au traitement des sédiments de dragage marins en vue de leur valorisation en techniques routières

International audienceIn this paper, results for an European project called SETARMS which aims to find innovative and sustainable solutions for marine dredged sediments in order to reuse them in road construction. After a first stage of a geotechnical characterization of sediments according to the GTR, the GTS recommendations were adopted to treat sediments with hydraulic binders. Hence, a formulation composed of 3% of quicklime and 6% of cement was applied for height different sediments. Specific ability tests were conducted in order to measure volumetric swelling and indirect tensile strength. Obtained results show that even if raw sediments belong to the same GTR class (A1 or A2), the treated samples respond differently to the adopted treatment formulation. Results of mechanical performance with the cure age show that most sediments don’t reach the needed criteria for reuse as sub-grade layer.Les résultats présentés dans cet article s’inscrivent dans le cadre du projet de recherche Européen SETARMS dont l’un des objectifs consiste à trouver des solutions innovantes et durables pour la gestion des sédiments marins dragués en Manche (France-Angleterre) pour une application en techniques routières, plus particulièrement en couche de forme. Après une 1ère étape de caractérisation géotechnique des sédiments de dragage selon le GTR, les recommandations du GTS ont été utilisées pour le traitement des sédiments aux liants hydrauliques. Ainsi une formulation à 3 % de chaux et 6 % de ciment est appliquée à huit sédiments. Des essais d’aptitude au traitement comprenant des mesures de gonflements volumiques (Gv) et de résistances à la traction indirecte (Rit) ont été réalisés sur les huit sédiments traités en adoptant les normes standards en vigueur en France. Les résultats obtenus montrent que malgré une même origine des sédiments et des classes GTR assez proches (A1 et A2), les sédiments traités répondent différemment aux essais d’aptitude. Ces premiers résultats, utiles à l’avancement du projet, permettent une meilleure compréhension de la problématique de traitement des sédiments aux liants hydrauliques et leur valorisation en techniques routières

Etude expérimentale et numérique du renforcement des tabliers de ponts en béton armé par des rechargements adhérents

The work developed in this report is part of research programme of the University of Sherbrooke, the purpose of which is to make technical recommendations for the durable repair of slabs of bridge deck. Following a bibliographical synthesis, we led a study in laboratory to analyze the structural behaviour of reinforced concrete slabs repaired using an adherent overlaying. The experimentation rested on a pilot slab and four slabs overlay according to different configurations (thickness of concrete, reinforcemen steel, anchorings). These slabs underwent several cycles of static and cyclic loading in pure bending in order to follow their behaviors in time. The experimental results made it possible to appreciate the good performance of three of the four configurations on the debonding of repair and the structural behavior of the slabs. To consolidate the noted were used two computer codes by finite elements (MSC., MARC/MENTAT, ABAQUS 6.4.1) for, on the one hand, reproducing and to validate structural slabs repaired and for, on the other hand, analysing comprise it the constraints generated on the interface support-overlaying. The whole of the work realised within the framework of this thesis makes it possible to propose new techniques of repair of slabs of reinforced concrete bridge decksLe travail développé dans ce rapport s'inscrit dans un programme de recherche de l'Université de Sherbrooke, qui a pour but de formuler des recommandations techniques pour la réparation durable de dalles de tablier de pont. Suite à une synthèse bibliographique, nous avons conduit une étude en laboratoire pour analyser le comportement structural de dalles en béton armé réparées à l'aide d'un rechargement adhérent. L'expérimentation a reposé sur une dalle témoin et quatre dalles resurfacées selon les configurations différentes (épaisseur de béton, barres d'armature, ancrages). Ces dalles ont subi plusieurs cycles de chargement statique et cyclique en flexion simple afin de suivre leurs comportements dans le temps. Les résultats expérimentaux ont permis d'apprécier la bonne performance de trois des quatre configurations sur le décollement de la réparation et sur le comportement structural de a dalle. Pour conforter ces constations nous avons utilisé deux codes de calcul par éléments finis (MSC.MARC/MENTAT, ABAQUS 6.4.1) pour, d'une part, reproduire et valider le comportement structural des dalles réparées et pour, d'autre part, analyser les contraintes engendrées au niveau de l'interface support-rechargement. L'ensemble des travaux réalisés dans le cadre de cette thèse permet de proposer de nouvelles techniques de réparation de dalles de tabliers de ponts en béton armé.BETHUNE-BU Sci. appli. et éco. (621192101) / SudocSudocFranceCanadaFRC