SedNet conference 2021

VALSE - From dredging to the realisation of a cycle path using sediments

Jul 1, 2021 | 1:10 PM - 1:15 PM

The dredging of waterways sediments is an essential operation in order to maintain navigation and prevent flooding risks. It is usually done using a bucket excavator. The sediments are then transported by barge to a temporary dewatering area. After a few months stored in this area, the sediments are dry enough to be handled in agglomerated form. They may then follow several successive screening and crushing stages in order to obtain an desirable particle size. The sediment can thus be incorporated as a raw material for the manufacture of concrete, as a sand substitute. We were able to converge towards a concrete composition that is both technically and environmentally viable, on the basis of the knowledge acquired through project research on marine sediments, on the characterisation of fluvial sediments, on their specific preparation as well as the formulation methodology developed. Experimental laboratory research has thus enabled the development of a road base concrete formula, incorporating around 220 kg of dry sediment per cubic meter of fresh concrete. A section of cycle path was built using this experimental concrete on May 11, 2021 in Chatelet, Belgium. Mechanical and environmental monitoring of this track is currently underway. Geomechanical monitoring involves carrying out various tests: tests of compression, direct traction, water absorption and resistance to freeze-thaw, performed at several time intervals on concrete cubes and cores. Environmental monitoring, for its part, includes the analysis of runoff water but also leaching tests on crushed concrete. The construction of this cycle path with waterways sediments constitutes a considerable advance in the field of beneficial use of this type of sediment. The full results will be presented in a few months at the VALSE project final conference.