Abstract: The treatment of dredged sludge with high initial water content is very important in geotechnical engineering. Based on the traditional cement-treatment method, a new solidification additive by mixing cement, lime and polymer is proposed, in order to reduce the dredged sludge’s water content and increase unconfined compressive strength rapidly and broaden the water content of cement-treatment method so as to achieve efficient treatment of high water content dredged sludge. A series of laboratory tests have been performed to investigate the variation of unconfined compressive strength and the relationship between material mixing ratio and unconfined compressive strength. The experimental results show that the unconfined compressive strength of solidified sludge increased remarkably by adding cement and lime. The new composite additive could solidify the high liquid limit sludge with initial water content more than 2 times of the liquid limit just with low cement dosage, while its early strength is more than 0.5 MPa, 28 d strength is more than 1 MPa. Finally, a prediction expression of unconfined compressive strength is proposed and verified.

Key words: high water content, dredged sludge, solidification, unconfined compressive strength (UCS)