Valorization of dredged sediments in self-consolidating concrete: Fresh, hardened, and microstructural properties

Several studies have proven the use of dredged sediments as supplementary cementitious materials (SCMs), but limited information is available on the effect of such treated sediments on self-consolidating concrete performance. The main objective of this study was to evaluate the performance of self-consolidating concrete (SCC) fabricated with treated sediments. The sediments were thermally treated at 800 °C for 1 h. The packing density of the granular skeleton was optimized to reduce the paste content and produce SCC with relatively low binder content. Three different SCC mixtures were prepared with 0%, 10%, and 20% cement replaced with treated sediments by mass. Key fresh, physical, hardened, and microstructural properties of the investigated SCC mixtures subject to different curing regimes were evaluated. The test results showed that the optimized SCC mixtures exhibited adequate self-consolidation characteristics. The particle size and high chemical activity of the sediments led to pore refinement of micro-pores, increased density, improved microstructure, and reduced micro-cracks of the investigated SCC mixtures. Furthermore, the use of up to 20% of treated sediments resulted in a compressive strength of 66 ± 1 MPa at 91 days, which is comparable to that of the reference mixture made without any sediments. Leaching test results confirmed the ecological potential of producing SCCs based on sediments, which could be an interesting alternative of using local materials to reduce the high demand of cement, thus further reducing the CO2 footprint of concrete structures.