Feasibility study of chemical stabilization of dredged marine sediment
Résumé
Chemical stabilization is one of techniques which can improve mechanical and hydraulic properties of dredged sediments. This paper presents an experimental study focused on different techniques of stabilization of dredged sediment from La Baule-Le Pouliguen (France). Dredged sediments are stabilized with lime, Portland cement and fly ash. Three mixes were produced and submitted to uniaxial compression strength (UCS), indirect tensile strength (ITS) and shear tests at different curing ages. In addition, suction and mercury porosimetry tests are performed to highlight the effect of binders on the microstructure of treated sediment. Results indicated sediment treated with lime plus cement and fly ash, is promising, despite the time necessary to obtain the threshold of UCS (1MPa); unfortunately, ITS reference value (0.25 MPa) was not obtained. But this mixture presented good performance of shear strength parameters, exhibiting higher increases in cohesion (c) and friction angle (f) compared to the others mixes. In terms of porosimetry and suction results, it was observed that each type of binder acts differently, changing initial unimodal to bimodal porous distribution curves, and reducing suction in treated sediment due to macroporous occurrence and water retention for chemical reaction.