Traditional approaches such as ocean dumping and inland deposit are unsatisfactory for the management of dredged sediments, in the context of sustainable development. The solidified sediments with fly ash and lime as road base materials are preferred to conserve land and minimize impact to environment. A series of tests, such as compaction tests, tensile strength tests and swell tests, were performed to explore mechanical and swell properties of Dunkirk dredged materials. The fly ash contributes to the considerable increase in elastic modulus and the small increase in tensile strength in the presence of lime. Then the potential of treated sediments as road base material is evaluated. After immersion in water for 4 days, the addition of fly ash can induce a remarkable increase in swell percents in contrast with the lime-based sediments.