Potential use of Amazon River sediment as supplementary cementitious material

Abstract

The Amazonian cities located along the Amazon River rely on river transport to ensure their supply and economic sustainability. However, the accumulation of sediments transported by the river frequently obstructs strategic navigation routes, requiring annual dredging campaigns that remove millions of tons of material, which are typically discarded without economic utilization. Amazon River sediment, however, has immense potential for use as a supplementary cementitious material due to its chemical composition (SiO₂ + Al₂O₃ + Fe₂O₃ = 91.49%) and mineralogical characteristics, which allow its incorporation into cement without compromising essential properties. In this context, this study investigated the partial replacement of up to 30% of Portland cement with sediment, analyzing its properties both in the short term (28 days) and long term (2 years). The results demonstrated that this replacement reduces cement consumption without compromising compressive strength or performance in terms of permeability. In addition to providing a sustainable solution for managing dredged sediments, this approach contributes to mitigating the environmental impacts of the cement industry. Since it does not require calcination, the sediment eliminates the need for thermal energy in its processing, making it a more eco-efficient alternative.