Resistance of concrete based on treated mud to sea water attack

All the dams in the world are exposed to the phenomenon of sedimentation, but with velocities that differ from one region to another. This phenomenon has been widely reported in Algeria. Dredging is a vital activity in the operation of dams, but the amount of sediment discharged by dredging operations downstream of the structure can lead to long-term pollution of the rural environment. This study focuses on the valorization of the vases resulting from these dredging operations at the dams as the case of Chorfa dam (western Algerian). The objective is to propose economically competitive formulations that are easy to implement and which allow these materials to be used in the manufacture of ordinary concretes by partial substitution of cement (10, 20 and 30%). The sludge is treated by calcination at 750°C to make it active. Seawater attack tests were conducted on the concretes to determine their durability. The results obtained confirmed the possibility of developing concretes incorporating the calcinated sludge at dosages of up to 30% without compromising the quality of these concretes in terms of behavior against seawater aggressions meeting the economic, ecological and technological objectives

Resistance of concrete based on treated mud to sea water attack

All the dams in the world are exposed to the phenomenon of sedimentation, but with velocities that differ from one region to another. This phenomenon has been widely reported in Algeria. Dredging is a vital activity in the operation of dams, but the amount of sediment discharged by dredging operations downstream of the structure can lead to long-term pollution of the rural environment. This study focuses on the valorization of the vases resulting from these dredging operations at the dams as the case of Chorfa dam (western Algerian). The objective is to propose economically competitive formulations that are easy to implement and which allow these materials to be used in the manufacture of ordinary concretes by partial substitution of cement (10, 20 and 30%). The sludge is treated by calcination at 750°C to make it active. Seawater attack tests were conducted on the concretes to determine their durability. The results obtained confirmed the possibility of developing concretes incorporating the calcinated sludge at dosages of up to 30% without compromising the quality of these concretes in terms of behavior against seawater aggressions meeting the economic, ecological and technological objectives

Influence du pourcentage de substitution en sédiment traité sur l’ouvrabilité, la résistance et la porosité des BAP

Sediment dredging is often confronted with the problem of eliminating the quantities of extracted mud. This issue has given rise to valorization policy in order to provide an alternative to the storage and disposal of dredged sediments. This study concerns the developing of self-compacting concretes (SCC) by substituting partialy cement with sediment dredged from Chorfa dam (Algeria) after being calcined. The results showed that a substitution up to 30% of cement with calcined mud in SCC seems feasible according to the found mechanical performances which were close even better than those of the reference SCC. Moreover, the studied SCC showed very fine porosities which make of them potentially sustainable SCC’s.Le dragage des sédiments se retrouve souvent confronté au problème d’élimination des quantités de vase extraites. Ce même problème a donné naissance à la politique de valorisation afin de fournir une alternative au stockage et au rejet des sédiments dragués. Cette étude consiste à élaborer des bétons autoplaçants en substituant partiellement le ciment par de la vase issue du barrage Chorfa (Algérie) après calcination. Les résultats obtenus montrent qu’une substitution allant jusqu’à 30% du ciment par de la vase calcinée dans des BAP semble réalisable tout en ayant des performances mécaniques proches, voire meilleures que celles d’un BAP de référence. Outre les résistances mécaniques, les différents BAP de l’étude présentent des porosités très fines qui font d’eux des BAP potentiellement durable.Le dragage des sédiments se retrouve souvent confronté au problème d’élimination des quantités de vase extraites. Ce même problème a donné naissance à la politique de valorisation afin de fournir une alternative au stockage et au rejet des sédiments dragués. Cette étude consiste à élaborer des bétons autoplaçants en substituant partiellement le ciment par de la vase issue du barrage Chorfa (Algérie) après calcination. Les résultats obtenus montrent qu’une substitution allant jusqu’à 30% du ciment par de la vase calcinée dans des BAP semble réalisable tout en ayant des performances mécaniques proches, voire meilleures que celles d’un BAP de référence. Outre les résistances mécaniques, les différents BAP de l’étude présentent des porosités très fines qui font d’eux des BAP potentiellement durable

Influence du pourcentage de substitution en sédiment traité sur l’ouvrabilité, la résistance et la porosité des BAP

Sediment dredging is often confronted with the problem of eliminating the quantities of extracted mud. This issue has given rise to valorization policy in order to provide an alternative to the storage and disposal of dredged sediments. This study concerns the developing of self-compacting concretes (SCC) by substituting partialy cement with sediment dredged from Chorfa dam (Algeria) after being calcined. The results showed that a substitution up to 30% of cement with calcined mud in SCC seems feasible according to the found mechanical performances which were close even better than those of the reference SCC. Moreover, the studied SCC showed very fine porosities which make of them potentially sustainable SCC’s.Le dragage des sédiments se retrouve souvent confronté au problème d’élimination des quantités de vase extraites. Ce même problème a donné naissance à la politique de valorisation afin de fournir une alternative au stockage et au rejet des sédiments dragués. Cette étude consiste à élaborer des bétons autoplaçants en substituant partiellement le ciment par de la vase issue du barrage Chorfa (Algérie) après calcination. Les résultats obtenus montrent qu’une substitution allant jusqu’à 30% du ciment par de la vase calcinée dans des BAP semble réalisable tout en ayant des performances mécaniques proches, voire meilleures que celles d’un BAP de référence. Outre les résistances mécaniques, les différents BAP de l’étude présentent des porosités très fines qui font d’eux des BAP potentiellement durable.Le dragage des sédiments se retrouve souvent confronté au problème d’élimination des quantités de vase extraites. Ce même problème a donné naissance à la politique de valorisation afin de fournir une alternative au stockage et au rejet des sédiments dragués. Cette étude consiste à élaborer des bétons autoplaçants en substituant partiellement le ciment par de la vase issue du barrage Chorfa (Algérie) après calcination. Les résultats obtenus montrent qu’une substitution allant jusqu’à 30% du ciment par de la vase calcinée dans des BAP semble réalisable tout en ayant des performances mécaniques proches, voire meilleures que celles d’un BAP de référence. Outre les résistances mécaniques, les différents BAP de l’étude présentent des porosités très fines qui font d’eux des BAP potentiellement durable

Drability of self compacting concretes with silt and pozzolan

RésuméEn raison des spécificités relatives à la formulation des bétons autoplaçants (BAP) et en particulier ceux concernant leur volume élevé en pâte et la présence d'ajouts et substituts minéraux en grande quantité, leur comportement à l'état frais et à l'état durci ainsi que leur durabilité sont fortement influencés par ces deux paramètres.Certains sédiments traités acquièrent des propriétés pouzzolaniques et peuvent être utilisés en tant qu'ajouts ou substituts au ciment. Ceci peut faire de la technologie des bétons une voie privilégiée pour leur valorisation.La présente étude vise à apporter une contribution à la valorisation de la vase traitée du barrage de Chorfa et de Fergoug, (situé à l'ouest algérien) en tant que substitut minéral partiel au ciment CPA CEMI 42.5 dans la composition des mortiers et des bétons autoplaçants. Il s'agit de comparer l'influence de l'incorporation de cette vase calcinée à celle de la pouzzolane naturelle de Béni-Saf (situé, également à l'ouest algérien) dans les BAP sur leurs caractéristiques physico-mécaniques et sur leur durabilité à court, moyen et long terme.L'étude est menée sur quatre BAP, le premier à base de 20 % de pouzzolane naturelle de Béni-Saf (BAP-PZ), le deuxième et le troisième incorporant 20 % de la vase calcinée issue des sédiments de dragage du barrage de Fergoug (BAP-VF) et de celui de Chorfa (BAP-VC) et enfin un BAP témoin sans ajouts pour le besoin de comparaison.Outre l'intérêt économique que présentent les BAP à base de la vase calcinée, notre étude a montré que ces derniers représentent des performances très comparables à celles obtenues sur des BAP à base de pouzzolane naturelle (BAP-PZ).En effet, Concernant les résistances à la compression, notre étude indiquent que les BAP à base de vase ((BAP-VC) et (BAP-VF)) présentent les meilleurs résultats notamment à long terme.Les résultats des essais de l'attaque acide (HCl et H2SO4), l'attaque sulfatique (Na2SO4 et MgSO4) et de carbonatation accélérée, montrent que la vase calcinée a une influence sensiblement meilleure que celle de la pouzzolane sur les propriétés physico-mécaniques et la durabilité des bétons dans lesquels elle est incorporée.Mots clés : Barrage de Chorfa - Barrage de Fergoug –Vase calcinée – pouzzolane – BAP à base de vase – BAP à base de pouzzolane – Résistances mécaniques –Durabilité.AbstractBecause of the specificities of self-compacting concrete (SCC), especially regarding their high volume paste content and the presence of large amounts of mineral admixtures and substitutes, the behavior in fresh and hardened state and the durability of these concretes are strongly influenced by these two parameters.Some treated sediments acquire pozzolanic properties and can be used as additions orsubstitutes to the cement. This possibility makes of concrete technology a privileged way of enhancement.The present study aims to contribute to the enhancement of the treated mud of Chorfa and Fergoug dam (situated in west of Algeria) as a mineral partial substitute for CPA CEMI 42.5 cement in the composition of an economic and preferment mortars and self-compacting concretes. The aim is to compare the influence of the incorporation of this calcined mud to the natural pozzolana of Beni Saf (situated, also in west of Algeria) in (SCC) on their physical, mechanical behavior and their durability of these concretes in short, medium and long term.The study was conducted on four SCCs, the first based on 20% natural pozzolana Beni Saf (SCC-PZ), the second based on 20% of the calcined mud of Fergoug dam (SCC-VF) and of Chorfa dam (SCC-VC) and a control SCC without additions to the need for comparison .Apart from the economic interest of the SCCs based on calcined mud, our study showed that these concretes have comparable performances to that obtained on SCC based on natural pozzolana (SCC-PZ).In fact, concerning compressive strengths, our study indicate that the SCC with calcined mud ((SCC-VC) and (SCC-VF)) present the best results especially at long termThe results of the different following tests: the acid attack (HCl and H2SO4), carbonation and sulphate attack (Na2SO4 and MgSO4) show that the calcined mud has an influence roughly better than the natural pozzolana on the physic - mechanical behavior and durability of the SCC which it is incorporated.Key words: Dam of Chorfa – Dam of Fergoug – Calcined mud – Pozzolana – SCCcontaining mud - SCC containing pozzolana – Mechanical strength –Durability

Influence of treated sediment substitution percentage on workability, strength and porosity of SCC

Sediment dredging is often confronted with the problem of eliminating the quantities of extracted mud. This issue has given rise to valorization policy in order to provide an alternative to the storage and disposal of dredged sediments. This study concerns the developing of self-compacting concretes (SCC) by substituting partialy cement with sediment dredged from Chorfa dam (Algeria) after being calcined. The results showed that a substitution up to 30% of cement with calcined mud in SCC seems feasible according to the found mechanical performances which were close even better than those of the reference SCC. Moreover, the studied SCC showed very fine porosities which make of them potentially sustainable SCC’s

Valorization of Dredged Sediments as a Component of Vibrated Concrete: Durability of These Concretes Against Sulfuric Acid Attack

Abstract Hydraulic facilities are subjected to significant siltation which, in a very short period of time, can render them unusable. In Algeria, the silting-up of a great number of dams, built for drinking water needs and for irrigation, implies the necessity and urgency to take action. Therefore, the maintenance work, which leads to dredging the deposited silt, constitutes an unbearable obligation for the preservation of the environment. Chorfa dam (western Algeria) may be mentioned as a concrete example. This study is part of a long research whose objective is to contribute to the valorization and the optimization of the formulations economically that are easy to implement and which enable to use the dredged materials in the formulation of ordinary concretes by partial substitution to cement (10, 20 and 30%) of dredged sediments, after calcination at 750 °C to make them active. Tests were carried out on concrete that was vibrated in the fresh state (setting time) and hardened state (compressive strengths and durability of concrete exposed to sulfuric acid attack) in order to determine their characteristics. The results obtained confirmed the possibility to develop concretes containing calcined silt, with proportions up to 30%, and which can meet the economic, ecological and technological objectives

Proposal of industrialization process of dredged sediments

Our study will focus on life cycle assessment (LCA) of dredged sediments in its environment from sediment extraction to waste treatment. This tool is part of an environmental management approach, to compare the environmental loads of the different stages of the life cycle of the same product and to deduce which stage of the scenario is the most polluting in environmental terms. Optimize the modeling of industrialization process of dredged sediments using the SimaPro 8.2.3 software to propose a model that is the most respectful of the environment. We will focus on the environmental impacts; we will try to propose the most environmentally friendly scenario to exploit these dredged sediments in the field of building construction

Influence of calcined mud on the mechanical properties and shrinkage of self-compacting concrete

The use of SCC has a particular interest in terms of sustainable development. Indeed, their specific formulation leads to a greater volume of dough than for common concretes, thus, a larger quantity of cement. However, for economical, ecological and technical reasons, it is sought to limit their cement content [1]. It is therefore necessary to almost always use mineral additions as a partial replacement for cement because the technology of self-compacting concretes can consume large quantities of fines, in this case calcinated mud issued from dams dredging sediments that can give and/or ameliorate characteristics and performances of this type of concretes. Four SCCs had been formulated from the same composition where the only percentage of calcinated mud of Chorfa (west of Algeria) dam changed (0%, 10%, 20% and 30%). The effect of calcinated mud on characteristics at fresh state of SCC according to AFGC was quantified. Mechanical strengths and shrinkage deformation (total, autogenous, drying) were evaluated. The results show the possibility to make SCCs with different dosages of calcinated mud having strengths that can defy those of the control SCC. The analysis of free deformations indicates the beneficial impact of the mud by contributing to decrease the amplitudes of the shrinkage compared to those of the control SCC

Proposal of industrialization process of dredged sediments

Our study will focus on life cycle assessment (LCA) of dredged sediments in its environment from sediment extraction to waste treatment. This tool is part of an environmental management approach, to compare the environmental loads of the different stages of the life cycle of the same product and to deduce which stage of the scenario is the most polluting in environmental terms. Optimize the modeling of industrialization process of dredged sediments using the SimaPro 8.2.3 software to propose a model that is the most respectful of the environment. We will focus on the environmental impacts; we will try to propose the most environmentally friendly scenario to exploit these dredged sediments in the field of building construction