Marine dredged sediment based cementitious matrix: thermal treatment, physical properties and prediction using response surface methodology.

Dredging is a necessary activity to control the natural accumulation of sediments at the bottom of the harbor. The management of dredged sediments is a complex issue; the main answer to the question of the fate of polluted sediments dredged was to release them at sea. However, mentalities have changed and respect for the environment is becoming more and more important in the decision-making process. In this context, the use of sediments as an artificial pozzolanic material became an important environmental impact and economic issue. This work addresses the objective of using natural and calcined sediments in the sustainable production of mortar in fresh and hardened states. Four samples were obtained by substituting Portland cement (CEM I 52.5 N) with calcined (SC) of uncalcined (sediment (S) (10, 20, 30, and 40 wt%). X-ray diffraction showed a real advantage of heat treatment of sediments to acquire pozzolanic behavior. In fact, the best mechanical properties, superior to the control mortars, were obtained for mortars with 10 wt% of sediment with values of 35.14 and 47.99 MPa at 7 and 28 days of curing, respectively. The flexural strength reaches values of 9.17 at 90 days of curing. The leaching test of the samples shows that the incorporation of 10 wt% sediment in mortars does not affect the performance of the samples, which explains the immobilization and the stabilization of the heavy metals in the matrix of the mortar. The derived models not only demonstrated the feasibility of predicting crucial material characteristics but also provided a systematic approach for optimizing sediment utilization.