The Use of Dredged Marine Sediment in the Formulation of Air-Foam Concrete

Huge quantities of sediments are dredged continuously worldwide. They are generally dumped in landfill areas, with the ensuing costs of dredging operations and in soil-groundwater pollution. The objective of this work is to study the beneficial reuse of dredged sediments in foam mortar and particularly to study the influence of the substitution of sand by dredged sediments. Air-foam concrete is an alternative to ordinary concrete, which presents the advantages of being lightweight and having low thermal conductivity. In this study, the density required ranges from 1200 to 1600 kg/m(3). Air foam can be used as concrete building blocks and slabs for load-bearing and non-load-bearing structures. 20 foam mortar mixes were prepared. Sediments were introduced by replacing 15%, 30%, and 50% mass of the sand. The foam percentage was introduced from 0 to 100% volume of mortar. Workability, compressive strength, and flexural strength were measured at 7, 28, and 60 days. The foam-bubble size distribution and the effect of sediments on their stability were also studied. The results show that sediment can be used as a sand alternative for foam concrete. The air-foam concrete's strength was increased with the substitution of sediment. This increase is linked to the density increase that is caused by the collapse of the air foam during mixing, highlighting a compromise between this material's weight and strength. [GRAPHICS] .