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In order to prepare a new type of fine-grained concrete without coarse aggregate instead of ordinary concrete usingdredged sand in channels, the physical and mechanical properties, such as mobility, compressive strength and abrasionresistance of fine-grained concrete filled with limestone powder and fly ash were compared and analyzed, and the influence ofdifferent mud contents (1.3%, 5.3%, 9.3%, 13.3%) of dredged sand on the performance of fine-grained concrete was explored.The results showed that the maximum bulk densities of dry mixed materials filled with fly ash and limestone powder were2 083.8 kg/m³ and 1 979.9 kg/m³, respectively. The ratio of filler to sand was 0.13 and 0.10, and the compressive strength at 28days was 39.8 MPa and 34.1 MPa, respectively; Compared to the 1.3% mud content, the compressive strength of fine-grainedconcrete with a mud content of 13.3% filled with fly ash at 3 days, 28 days, and 90 days decreased by 27.8%, 13.5%, and16.4%, respectively. Samples with lower mud content have higher apparent density, lower bleeding capacity, and better waterretention and workability. The prepared fine -grained concrete can replace ordinary concrete to prepare small prefabricatedblocks such as pavement bricks, interlocking blocks, fish groove bricks, and twisted king blocks, which can be applied nearbyin waterway regulation, roads, or municipal engineering. [ABSTRACT FROM AUTHOR]

Port structures (quays and dykes) need an enormous consumption of materials, in particular concrete and its components, as well as sand, hence the need to develop alternative solutions using port dredging sand, estimated at thousands of tonnes through its use in the concrete that forms the blocks of the quay walls. After having demonstrated in a previous work the possibility of using the dredged sand from the port of Agadir in concrete formulations, the present work consists in showing the possibility of using the dredged sand from the port of Agadir in concrete formulations that can be used in the construction of concrete tetrapods from a concrete formulation based on dredged sand, more precisely 50% of the sand entering in the formulation is dredged sand extracted from the port of Agadir. The eventual use of dredged sand in the concrete of the tetrapods will lead to enormous gains in the quantities of sand and thus to a lower consumption of construction materials, and will also play a more important role in the preservation of the marine environment by avoiding the trapping of the dredged materials.