Statistical analyses of sustainable cement mortars mechanical strenght

Sediment dredging involves the release of huge volumes of materials, whose management is one of the priority issues to be addressed to limit landfilling. Reuse options for dredged materials must be identified, following their characterization; according to the circular economy principles and in compliance with the Agenda 2030 provisions, one of the most promising is using sediments to make cement conglomerates. From sediments sampled from the Camastra and San Giuliano reservoirs, located in Basilicata, a region in southern Italy, cement mortars have been obtained, first by completely replacing the aggregate with sandy downstream material in varying quantities and then also by partially replacing the binder in constant quantities. In the present work, the relationship between the amount of sandy aggregate replaced in mortars and the compressive strength of the mortars is investigated by statistical analysis. The compressive strengths found for the SG_s1 (60 MPa) and SG_s2 (52 MPa) specimens are significant, as they are approximately 15% higher than the normalized mortar, the reference. On the contrary, all mortars prepared with the Camastra sediments exhibit compressive strengths approximately 50% lower than the normalized mortar. Statistical analyses show that the compressive strengths depend on the content of sandy material used, concerning the specimens in which only the aggregate was entirely replaced by the downstream sediment. In contrast, if the upstream clay material is used instead of part of the binder, there is no statistical correlation between the compressive strength values and the content of the sandy material used.