Study of the mechanical and calorimetric properties of cement mortar incorporating thermally treated marine sediments

Dredging marine sediments generates millions of tons of waste annually, posing a major environmental and economic challenge. Reusing these materials in civil engineering offers a sustainable alternative for construction resources. This study investigates the potential of incorporating raw and heat-treated marine sediments from Algerian ports as partial replacements for CEM I 52.5 Portland cement at substitution rates of 10%, 20%, 30%, and 40%. The mechanical and physical properties of the resulting mortars were evaluated. Results show that compressive strength decreases with increasing sediment content; however, mortars with 10% substitution display strengths comparable to the reference mix, likely due to the sediments' reactivity with lime released during hydration. The consistency of mortar containing calcined marine sediments at substitution rates of 10% to 30% exhibits an accelerated initial setting time, while its final setting time is delayed. These initial and final reactivities can be attributed to variations in the processes of the pozzolanic reaction and cement hydration. Analysis of the heat of hydration further confirms pozzolanic reactions and latent hydraulic activity in the treated sediments, highlighting their potential for sustainable cement-based applications.