Valorisation of sediments in self-consolidating concrete: Mix-design and microstructure

This study deals with the potential use of treated sediments (TS) in self-consolidating concrete. The compressive strengths of mortars have shown a significant activity of TS with cement. This activity is directly related to the particle size distribution of TS, as a higher coefficient of activity was observed for finer TS-powders. Therefore, treated sediments could be used as cementitious materials. TS were incorporated in self-consolidating concrete design as a replacement of limestone filler and aggregates. The average compressive strength of sediment-based concrete specimens is comparable to that of reference concrete. However, the use of TS resulted in a decrease in slump flow due to the high internal porosity of TS. Rheological tests have been carried out on pastes to assess the loss of workability observed on mortars and concrete. An increase in yield stress and plastic viscosity has been observed for sediment-based paste with respect to that of limestone filler leading to a lower slump flow since this parameter is closely related to yield stress. The microstructural analyses of concrete have shown the positive effect of TS on hydration at the microscopic level.