Publication Abstract

Proceedings of the Deep Mixing 2015 Conference, (DFI)

Three Mass Stabilization Phases in West Harbor in Helsinki, Finland - Geotechnical and Environmental Properties of Mass Stabilized Dredged Sediments as Construction Material
Juha Forsman, Ramboll Finland Oy, Finland; Noora Lindroos, Ramboll Finland Oy, Finland; Leena Korkiala-Tanttu, Aalto University, Finland

Construction works at the Helsinki city sea shoreline requires dredging and handling of contaminated sediments. Most of these soft dredged sediments are regarded as too poor quality material for earth construction purposes. Mass stabilization technology has been applied to improve the technical and environmental properties of the dredged sediment in order to utilize the material in construction. The treatment site presented in this article is placed in the West Harbor where the dredged sediments are disposed in basins, mixed with binders by mass stabilization and transported to utilization sites. The volume of these basins is about 90 000 m3. So far these basins have been used three times during the years 2011-2014. The most applied binder has been cement. Its high price and carbon footprint have encouraged use alternative binders. Other used binder materials include fly ash and end product of desulphurization from coal combustion, and fly ash from combustion of Estonian oil shale. The technical and environmental properties of stabilized sediments have been studies in the laboratory and in situ thoroughly. Some properties of the stabilized sediments which have been studied are: compression strength, modulus, hydraulic conductivity, leaching of contaminants, etc. The leaching test results show that heavy metal leaching is very low with all binder materials tested.

 article #2089; publication #1013 (DM-2015)