Dredged silt as a raw material for the construction industry

Past, present and prospective uses of dredged silt in the construction industry are discussed as part of the current BRE research programme on the utilisation of waste materials. The annual dredging commitments and methods of silt disposal are tabulated for the major port authorities. Silt samples from a selection of these ports were compared by their physical properties, by the production of sintered aggregates, and by chemical and mineralogical analysis. Larger quantities of synthetic aggregate from dredged silt have been used to produce concrete suitable for structural work. It is concluded that the most promising possibility for a new use of dredged silt lies in the production of aggregates. The heat treatment proposed reduces the content of deleterious impurities to insignificant levels and the results may be relevant in countries short of clean aggregates.