Beneficial use of dredged sediments in public works

With the increase in environmental awareness, in combination with a more restrictive legislation, traditional solutions to the management of dredged sediments, such as dumping at sea or disposal to landfills, become more and more inadequate. In order to improve the management of dredged marine sediments, alternative solutions such as beneficial use in civil engineering, manufacture or agriculture have been proposed. Reuse solutions have to fulfil economical, technical and environmental criteria. At present, the proposed solutions are relatively costly and not adaptable to all types of sediments. In particular, fine sediments are difficult to reuse in comparison to sands because of their high water content, the presence of organic matters, their mechanical behaviour and the presence of pollutants in some cases. In this context, this study aims to design a road material that includes dredged fine sediments from a harbour in the north of France. With an initial water content higher than 100%, the first operation consisted in preparing the dredged sediments by reducing its initial water content and, as a consequence, the content of dissolved salts. Then the sediments were characterized and finally a material with the required properties was designed. This material included fine marine sediments, traditional granular materials and hydraulic binders. This paper focuses on the methodology used to design the road material.