Geotechnical Characterization of Stabilized Dredged Sediments

Several hundred million cubic meters of sediments are dredged annually from the bottom of the rivers, canals, dams and waterways. This is carried out in order to achieve the required depth of the waterways and ports or to maintain the capacity of the reservoirs of the dams. Conventionally the dredged sediments were disposed in the oceans or alternatively were deposited inland. However, these procedures have become less attractive due to the environmental issues and the limited disposal space. An economical yet environmental solution is to utilize the dredged sediments as construction materials in e.g. transportation related projects. However, the geotechnical properties of the dredged sediments are not suitable for their utilization in civil engineering applications. In order to enhance the shear and compressive strength of the dredged sediments, various binder materials such as lime, fly ash, cement, quicklime, etc. are used. In this work, experiments have been carried out to investigate the influence of addition of cement as the binder material on the geotechnical properties of the dredged sediments with high water content. Laboratory tests of the stabilized dredged sediments have been performed with various water/solid ratios. Extensive characterization techniques were utilized to measure Unconfined Compressive Strength (UCS) with 7 and 28 days curing times. The bulk density, water content, specific gravity, organic matter, particle size distribution, Atterberg test for measurement of plastic and liquid limits of the dredged sediments have also been carried out. Based on the results obtained, an experimental model was developed for unconfined compressive strength of the stabilized dredged sediments. The model shows very good agreement with the results obtained. It is shown that the unconfined compressive strength is enhanced with an increased bulk density and decreased W/S ratio of the stabilized dredged sediments. The model proposed in this study provides the possibility of optimizing the amount of binder to be added to the dredged sediment in order to obtain the required strength of the dredged sediment for a specific application.Validerat; 20160131 (global_studentproject_submitter