About a possible valorisation in cementitious materials of polluted sediments after treatment

The disposal of contaminated dredged material has become all economical and environmental issue. Firstly, this study presents the Novosole process which was used for the treatment of polluted sediments. This process is based on the stabilisation of heavy metals and on the thermal elimination of organic matter. A physical characterization of the processed material reveals high porosity (60%) and water absorption (45%). Moreover, the treated sediment aggregate (TSA) has a relatively low strength and a high content of fine particles. Secondly, an experimental study on the feasibility of TSA introduction in cement-based materials was performed. Three mortars for which a given sand volume was replaced by the same sediment volume (33%, 66% and 100%) were designed. A strong increase of drying shrinkage was observed (up to 10 times higher, when compared to a reference mortar). Permeability remained virtually constant, though. There was a significant increase in strength for low to moderate substitution, while high incorporated quantity of sediment led to a strength on the same order of that of the reference mortar. (c) 2006 Elsevier Ltd. All rights reserved.