Infrastructure Sediments: From Resource to Territorial Re-use

The management of dredged sediments is confronted with the legislation in place for the protection of the environment, the scarcity of land-based disposal sites and the obligation of monitoring and control for offshore dumping-at-sea sites. The search for alternative solutions to dumping-at-sea is necessary when sediments are contaminated. Land-based disposal is only a temporary intermediate solution because space is very limited. The ultimate solution of disposal in waste centres is expensive and inappropriate for the volumes of dredged sediments that may be contaminated. Attempting to recover sediments is a major industrial issue. Reclaiming dredged sediments by combining them with binders or industrial co-products gives a whole new dimension to this issue by fully integrating environmental and economic aspects. Reclamation involves research into suitable stabilization/solidification treatment techniques and potential applications in the road and construction sectors. The aim is to treat sediment-sand-binder-additive mixtures with economical dosage and low CO2 emissions. The envisaged recoveries are therefore a function of the mechanical, environmental and economic performance of the product obtained. The technical, scientific and socio-economic stakes are high. Indeed, the evolution of legislation and the collective awareness of the inconvenience caused by current dredging methods and the scarcity of host sites impose the need for research on the enhancement of sediments. Stabilisation/solidification treatments based on hydraulic binders appear to be the most suitable from a technical and economic point of view. However, additions are necessary depending on the destination of the "product obtained", to guarantee the sufficient performance required for the final application. It would therefore be appropriate from an environmental and economic point of view to incorporate industrial co-products. Adding value to sediments, yes, but adding "waste or non-recovered products" is the attraction and concept of these composite mixtures for sustainable development.