Every year, millions of cubic meters of dams and restraints are dredged as part of the management and prevention procedures all over the world. These dredged sediments are considered as natural waste leading to environmental, ecological and even economic problems associated with their processing and depositing. Nevertheless, in the context of a sustainable development policy, a way of their management is open aiming at assessing the sediments as a building material and, particularly, as a new binder that can be industrially exploited and that can improve the physical, chemical and mechanical characteristics of the concrete. This study is a part of the research made at the Civil Engineering Department at the University of Mostaganem (Algeria) on the impact of the mud dredged from the Fergoug Dam on the behavior of self-consolidating concrete (SCC) in the fresh and hardened states, such as the mechanical performance and its impact on different deformations (shrinkage). The work aims to assess this mud in the SCC and to show possible interactions between the constituents. The obtained results provide the details needed for producing the SCC based on calcined mud. Keywords: sediment, calcined mud, self-consolidating concrete, fresh state, hard state, shrinkage Vsako leto po vsem svetu kot varovalni ukrep izkopljejo milijone kubi~nih metrov sedimentov iz jezov in zadr`evalnikov. Ti izkopani sedimenti so obravnavani kot naravni odpadek, ki povzro~a okoljske, ekolo{ke in celo ekonomske te`ave pri njihovi predelavi ali odlaganju. Vseeno, v kontekstu politike trajnostnega razvoja je postavljena pot za njihovo obdelavo, za oceno teh sedimentov kot gradbenega materiala in {e posebej kot novega veziva, ki ga je mogo~e industrijsko izkoristiti in ki lahko izbolj{a fizikalne, kemijske in mehanske lastnosti betona. Ta {tudija je del raziskovalnega dela, opravljenega na oddelku za gradbeni{tvo Univerze v Mostaganemu (Al`irija), o vplivu izkopanega mulja iz jezu Fergoug na vedenje samozgo{~evalnega betona (SCC) v sve`em in v strjenem stanju, na mehanske lastnosti in na razli~ne deformacije (kr~enje). Namen je oceniti to blato v SCC in pokazati morebitne interakcije med sestavinami. Prikazani rezultati so dobra mo`nost za izdelavo SCC na osnovi kalciniranega blata. Klju~ne besede: sediment, kalcinirano blato, samozgo{~evalni beton, sve`e stanje, trdo stanje, kr~enje

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This work aims to study the feasibility of making a geopolymer cement based on dredged sediments, from the Fergoug dam (Algeria) and to evaluate their construction potential particularly interesting in the field of special cementitious materials. These sediments due to their mineralogical composition as aluminosilicates; are materials that can be used after heat treatment. Sedimentary clays were characterized before and after calcination by X-ray diffraction, ATG / ATD, spectroscopy (FTIR) and XRF analysis. The calcination was carried out on the raw material sieved at 80 μm for a temperature of 750 ° C, for 3.4 and 5 hours. The reactivity of the calcined products was measured using isothermal calorimetric analysis (DSC) on pastes prepared by mixing an alkaline solution of sodium hydroxide (NaOH) 8 M in an amount allowing to have a Na / Al ratio close to 1 (1: 1). Also, cubic mortar samples were prepared with a ratio L / S: 0.8, sealed and cured for 24 hours at 60 ° C and then at room temperature until the day they were submited to mechanical testing. to check the extent of geopolymerization. The results obtained allowed to optimize the calcination time of 5 hours for a better reactivity of these sediments, and a concentration of 8M of sodium hydroxide and more suitable to have the best mechanical performances.

Every year, millions of cube meters are dredged from dams and restraints as an entertaining and prevention procedure all over the world. These dredged sediments are considered as natural waste leading to an environmental, ecological and even an economical problem in their processing and deposing.Nevertheless, in the context of the sustainable development policy, a way of management is opened aiming to the valorization of sediments as a building material and particularly as a new binder that can be industrially exploited and that improve the physical, chemical and mechanical characteristics of the concrete.This study is a part of the research works realized in the civil engineering department at the university of Mostaganem (Algeria), on the impact of the dredged mud of Fergoug dam on the behaviour of self-consolidating concrete in fresh and hardened state , such as the mechanical performance of SCC and its impact on the differed deformations (shrinkage). The work aims to valorize this mud in SCC and to show eventual interactions between constituents. The results obtained presents a good perspectives in order to perform SCC based in caclined mud.

Concrete is composed of a liquid phase (paste) and of a solid phase (aggregates with fixed gravel/sand ratio), the concrete self-compacting properties come necessarily from those of the paste. The present research is the continuity of a first phase of the testing already conducted, which resulted in obtaining an optimal self-compacting cement paste composition. This paste will be used to prepare a self-compacting concrete (SCC), while passing from the scale of the cement paste to that of the concrete, by injecting wet aggregate to the self-compacting paste. The excess paste theory was used to determine the thickness of the paste coating each aggregate with a given diameter of constituting granular skeleton, then generalized for the determination of the quantity of total paste allowing the flow of the concrete by decreasing frictions between the grains of its granular skeleton. This approach was also experimentally validated. The influence of the granular distribution was minimized by the use of the approach based on the determination of the average diameter of the aggregates. This required the determination of a homothetic factor “K” similar for all concretes with different aggregate grading. Formulation of a self-compacting concrete passes initially by the determination of a sufficient quantity of paste allowing its flow without frictions between its aggregates and to balance the mixture by the quantity of water retained by the aggregates. The self-compacting concrete characteristics would come from those of the cement paste which composes it.