Experimental study on river sediment incorporation in concrete as a full aggregate replacement: Technical feasibility and economic viability

Abstract

The reuse of river sediments as aggregates is a sustainable management technique that reduces waste from dredging operations and offers the potential to realize economic benefits. This research aims to evaluate the technical feasibility and economic viability of producing C30 class concrete made from sediments. Sediment from the Seine River Basin is characterized from a physical, environmental and mineralogical perspective before its incorporation into concrete as full substitute for conventional aggregates. The physical, mechanical and durability properties as well as the leaching of these concretes are then investigated. Sediment characterization shows that the physical properties (i.e. density, water absorption, and particle size) are close to those of conventional aggregates. The environmental and mineralogical characterization has proven that the studied sediments are inert and are mainly silico-calcareous materials. Experimental results reveal that a slight increase in cement dosage (less than 5%) yields a sediment concrete possessing properties similar to those of the control specimen with any effects remaining only marginal. Leaching tests indicate that the rate of pollutants released by the sediment-based concrete is of the same order of magnitude as that released by the control specimen. The economic viability study has found that the production of a C30 concrete based on sediment is 41 % less expensive. In-situ use of sediments in concrete prevents the carbon footprint of aggregate transport, which offsets that of additional cement for sediments-based concrete.