Valorization of stabilized river sediments in fired clay bricks: factory scale experiment

The objective of this study is to demonstrate the practical use of polluted river sediments after treatment into brick production. Consequently, a full-scale industrial experiment was conducted at a brick factory in the north of France. Polluted sediment was stabilized by the Novosol process and then was introduced in the mix-design with a substitution ratio of 15% as a partial replacement of quartz sand. Approximately 15,000 perforated sediment-amended bricks were produced. The produced bricks were then subjected to several qualification tests (compressive strength, freeze and thaw resistance, water absorption). The results obtained showed that the substitution of quartz sand by treated sediment resulted in a significant increase in brick compressive strength and firing shrinkage, and in a decrease in porosity and water absorption. Moreover, leaching tests performed according to different standards on substituted brick samples showed that the quantities of heavy metals leached from crushed bricks were within the regulatory limits. Thus substituted bricks can be regarded as non-hazardous material.