Approche économique et validation de méthodes de traitements aux liants hydrauliques de sédiments marins contaminés

Abstract

Pour une meilleure gestion a terre des sediments contamines, consideres comme dechets, une unite pilote de traitements a ete mise en œuvre sur un site experimental, proche de Toulon. Un large eventail de sediments portuaires representatif de la variabilite de ces dechets a ete achemine sur cette plate-forme pour y etre traite et valorise et ce, de maniere operationnelle dans le cadre du projet SEDI.MAR.D. 83. Un des objectifs du projet a concerne la valorisation des sediments a l'aide de liants hydrauliques. Pour ce faire, des essais de faisabilite de stabilisation/solidification sur des sediments pre traites ou directement traites, ont ete entrepris tant du point de vue mecanique qu’environnemental. L’analyse des nombreux resultats d’essais realises sur differents sediments portuaires a permis d’etudier la faisabilite technique de ce type de procede de traitement par liants, d’optimiser les dosages et les additifs a mettre en œuvre et de confirmer l'acceptabilite environnementale par rapport aux filieres de valorisation envisageables pour ces dechets comme materiaux routiers et de remblais – ouvrages en terre, talus paysagers, remblaiement de carriere, remplissage de cavites souterraines-. Les possibilites d’emploi d’un tel procede de traitement par liants hydrauliques sont discutees dans cet article et notamment la discrimination economique des traitements effectues en amont qui permettent d’ameliorer la qualite du sediment pre traite avant stabilisation/solidification par liant. Cet article fait partie d'un ensemble de contributions relatives au projet SEDI.MAR.D. 83, (AQUA et al.., 2009 ; BENOIT-BONNEMASON et al., 2009 ;  LEVACHER et al., 2009 ; SEBY et al., 2009). Translated version: Economical approach and validation of treatment methods using binders of contaminated marine sediments For a better environmental practice in the land management of contaminated sediments considered as waste material, a pilot plant with sediments processing units was installed on a port site near the city of Toulon in the south of France. A large panel of sediments, representative of their variability, has been gathered on this pilot area to be treated and reused. All these processing operations constitute the basis of the SEDI.MAR.D. 83 programme. As part of this programme, one of the objectives concerns the valorisation of marine sediments with hydraulic binders. To succeed in doing that, feasibility tests of stabilization/solidification with raw or pre-treated sediments have been performed. Mechanical and environmental aspects were considered together with the different applied treatments. A lot of tests were run on various port sediments. The obtained results which follow were analyzed and have lead to studying the technical feasibility and ability of the process using hydraulic binders. On one hand, the optimization of the percentages of each binder and additives, if used, was searched for the different mixtures. On the other hand, the environmental acceptability was checked with regards to the enforced regulations, with a view to reusing the treated sediments as material. The considered beneficial uses concern roads and embankments constructions, mainly earthworks, landscaped slopes, fillings of quarries or underground holes. The possible reuses are discussed here and finally, a simple economical approach is proposed taking into account the different ways of treatment applied to the sediments before the stabilization/solidification by binders. This paper is one of a series relative to the SEDI.MAR.D. 83 project, (AQUA et al, 2009; BENOIT-BONNEMASON et al, 2009; LEVACHER et al, 2009; SEBY et al, 2009). Keywords: Contaminated marine sediments; Treatment by binders; Stabilization/Solidification; Compressive strength; SEDI.MAR.D. 83 project.