Characterization of Tunisian marine sediments in Rades and Gabes harbors
Résumé
The objective of this article is to study the geotechnical and environmental characteristics of sediments dredged from two Tunisian harbors: Rades and Gabes. The first harbor represents the main facility place in the national transport chain. The second one is selected as its sediments present a serious ecological constraint caused by the discharge of wastes into the marine environment. These sediments are either discarded at sea or landfilled despite their harmful effects on the environment. The article is divided into three main sections. The first one presents the material that was carried for Rades and Gabes harbors. The conservation conditions and the used experimental tests are detailed. Geotechnical characterization includes the determination of the grain size distribution, the water content, the Atterberg limits, the methylene blue value, the specific area, the bulk density, the specific unit weight, the organic and carbonate contents. Environmental characterization is assessed by the determination of metals concentrations in a leaching solution. The second section deals with the description and analysis of geotechnical properties of Rades and Gabes harbors' sediments. The results obtained show that Rades harbor sediments are slightly sandy clayey silts whereas Gabes harbor sediments are silty sands characterized by a highly plastic clay fraction. Both of the two sediments don't exhibit a high organic content. Finally, chemical, mineralogical and environmental properties are presented and then analysed. The experimental results obtained show that Rades and Gabes sediments could be used as a sand substitute in the formulation of a new construction material. Gabes harbor sediments are more polluted than Rades harbor sediments.