Environmental life cycle assessment of industrialization process of calcined dredged sediments

This research focus on the life cycle assessment (LCA) of dredged sediments valorization. This tool is part of an environmental management approach, which makes it possible to compare the environmental loads of the different stages of the life cycle of the same product and, by the way to deduce the most polluting step in environmental terms and thus the industrialization process of dredging sediments of dams is optimized by modelling using the GEMIS (Global Emission Model for Integrated Systems) 4.95 software and the classification and characterization method. To propose a model that is the more respectful of the environment, by determining the most environmentally friendly scenario, in order to exploit these dredged sediments after calcination treatment to make them active in the field of the building’s construction. The results of this life cycle analysis study of the new industrialization process of dredged sediments show that climate change potential (GHG) is 0,246 ton of CO2eq/t of sediments, acidification potential is 4,55×10-4 ton of SO2 eq/t of sediments, the tropospheric ozone precursor potential is 9,97×10-4 ton of TOPP eq/t of sediments and the cumulative energy and exergy demand is 2506,75 in MJ/t of sediments, these values are compared to others carried out in Algeria

Environmental life cycle assessment of industrialization process of calcined dredged sediments

This research focus on the life cycle assessment (LCA) of dredged sediments valorization. This tool is part of an environmental management approach, which makes it possible to compare the environmental loads of the different stages of the life cycle of the same product and, by the way to deduce the most polluting step in environmental terms and thus the industrialization process of dredging sediments of dams is optimized by modelling using the GEMIS (Global Emission Model for Integrated Systems) 4.95 software and the classification and characterization method. To propose a model that is the more respectful of the environment, by determining the most environmentally friendly scenario, in order to exploit these dredged sediments after calcination treatment to make them active in the field of the building’s construction. The results of this life cycle analysis study of the new industrialization process of dredged sediments show that climate change potential (GHG) is 0,246 ton of CO2eq/t of sediments, acidification potential is 4,55×10-4 ton of SO2 eq/t of sediments, the tropospheric ozone precursor potential is 9,97×10-4 ton of TOPP eq/t of sediments and the cumulative energy and exergy demand is 2506,75 in MJ/t of sediments, these values are compared to others carried out in Algeria

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

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

Excess paste method to formulate a self-compacting concrete

On the basis of the principle that a concrete is composed of a liquid phase (paste) and a solid phase (aggregates with fixed gravel/sand ratio), the concrete self-compacting properties come necessarily from those of the paste. The present work 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

Environmental life cycle assessment of industrialization process of calcined dredged sediments

This research focus on the life cycle assessment (LCA) of dredged sediments valorization. This tool is part of an environmental management approach, which makes it possible to compare the environmental loads of the different stages of the life cycle of the same product and, by the way to deduce the most polluting step in environmental terms and thus the industrialization process of dredging sediments of dams is optimized by modelling using the GEMIS (Global Emission Model for Integrated Systems) 4.95 software and the classification and characterization method. To propose a model that is the more respectful of the environment, by determining the most environmentally friendly scenario, in order to exploit these dredged sediments after calcination treatment to make them active in the field of the building’s construction. The results of this life cycle analysis study of the new industrialization process of dredged sediments show that climate change potential (GHG) is 0,246 ton of CO2eq/t of sediments, acidification potential is 4,55×10-4 ton of SO2 eq/t of sediments, the tropospheric ozone precursor potential is 9,97×10-4 ton of TOPP eq/t of sediments and the cumulative energy and exergy demand is 2506,75 in MJ/t of sediments, these values are compared to others carried out in Algeria

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

D’un mode d’habiter à l’autre : modalités et significations de la réappropriation d’un pavillonnaire des Castors à Oran (Algérie)

En Algérie, au cours des années 1953-1958, la plupart des réalisations des lotissements pavillonnaires français des Castors se concentrent à Oran. Produites à l’époque coloniale en auto-construction, et conformément au modèle mis en œuvre en France, les habitations se disposent sous forme de « modèle pavillonnaire » stéréotypé et sont adaptées à une catégorie de la population européenne. Après le départ de cette population en 1962, ces lotissements pavillonnaires ont été transformés avec le temps par les nouveaux occupants algériens. À partir de cette « substitution », de nombreuses interrogations portent sur le mode de leur réappropriation. Le cas du lotissement des Castors Familiaux et Traminots (CFT) de Maraval (arrondissement d’El-Othmania à Oran), dans lequel nous avons effectué une enquête entre 2010 et 2013, nous a révélé l’importance des recompositions socio-spatiales à l’œuvre. Un processus d’appropriation a montré, d’une part, les contours des différentes formes de transformations qui prévalent dans leurs organisations, et a souligné l’importance du contrôle social et des valeurs sociohistoriques algériennes dans la dimension spatiale. Aussi, l’article propose de mettre en scène l’ampleur des mutations des modes d’habiter selon les dimensions pratiques et symboliques de l’espace, en précisant le rôle des transformations habitantes dans l’affirmation du statut social et économique des occupants. Cette recherche a pour objectif de questionner le devenir d’un patrimoine résidentiel pavillonnaire européen datant de la moitié du xxe siècle, dont les contours sont progressivement altérés.In Algeria during the years 1953-1958, most of the achievements of the French pavilions of « Castor » housing estates are concentrated in Oran. Produced during the colonial period in self-construction and in accordance with the model implemented in France, the houses are arranged in the form of a stereotyped « Pavilion model » and are adapted to a particular category of the European population. After the departure of this population in 1962, these residential suburbs have been gradually transformed by the new Algerian occupants. Starting from this « substitution », numerous questions relate the way of their re-appropriation. The case of the subdivision of Familiaux and Traminot Castors (CFT) from Maraval (district of El-Othmania in Oran), in which we conducted a qualitative survey between 2010 and 2013, revealed to us the importance of the socio-spatial readjustments. A process of appropriation that has defined, on the one hand, the contours of the different forms of transformation that prevail in their organizations, and has brought out, on the other hand, from the remodeling of the original pavilion model, a type of hybrid habitat, using Algerian and Western cultural references. Thus, the article proposes to show the extent of the changes in the mode of dwelling in the practical and symbolic dimensions of space, through new arrangements of facilities, and to highlight in particular, the role of residential transformations in the affirmation of the social and economic status of the purchasers. Its objective is to question the future of a European suburban residential heritage dating from the middle of the 20th century, whose outlines are progressively altered