This paper reports an experimental study carried out to investigate the influence of dredged sediments and shell powders on the transport properties of mortar. Blend based on the combination of marine by-products was used to replace a part of Portland cement, after thermal treatment. Cylindrical mortars and pastes were cast with water to binder ratio of 0.5 and 0.4, respectively. Control specimens were also cast. After 28 days of curing in water, the apparent porosity, the gas permeability, the chloride diffusion and accelerated carbonation was investigated. The results showed that the combination of dredged sediment and shell powder provides a positive effect on the transport properties. Besides, mortars containing 33% by weight of blend showed low gas permeability than that of the control mortar even apparent porosity is higher. In addition, the resistance to the chloride ingress is more pronounced for mortars with sediment:shell blend. The carbonation thickness is related to the carbonation age and replacement level. This blend proved better transport properties by the filler effect.