Reuse of Lake Sediments in Sustainable Mortar

Abstract

The study analyses the possible valorisation of lake sediments for sustainable mortar, in accordance with the principles of the circular economy, to obtain a sustainable material, since reuse occurs without any kind of preliminary treatment and preserves the consumption of virgin raw materials in the mix design. Moreover, it reduces the amount of water to be used in the mix since part of it is already contained in the sediments. The research was performed on sediments dredged from two artificial reservoirs, Camastra and San Giuliano, located in Basilicata, a region in southern Italy. Cement mortar was prepared by completely replacing, at different quantities, the fine aggregate and, for some of it, partially replacing, at a constant quantity, part of the binder. Workability, mechanical strength, and density were measured, as well as the possible release of contaminants. The investigations made it possible to assess the influence of replacing aggregate with sediment on mortar performance, showing that San Giuliano sediment produces mortar with great workability (~140%), comparable to that of normalised mortar. Similarly, the mechanical strengths of some specimens (SG_s1 and SG_s2) were approximately 60 MPa and 52 MPa, respectively (about 15% higher than that of normalised mortar). On the contrary, for the mortar prepared with the Camastra sediments, both workability and mechanical strength were ~50% lower than normalised mortar. Furthermore, the leaching test did not reveal contaminant release.

A Relevant Characterization and Compatibility for Reuse the Sediments from Reservoirs in Southern Italy

“…In conclusion, this research on the Camastra and San Giuliano reservoir sediments is the first step towards identifying potential alternative reuses to landfill disposal. In this regard, some research has already been started, mainly to verify the compatibility of sediments for reuse as aggregate and binder in the preparation of cement mortars, with preliminary evidence that was very encouraging [62].…”

Fabrication and Properties of Blended Calcium Sulfoaluminate Cements Based on Thermally Treated Reservoir Sediments

“…To recover the original capacity, dredging operations are carried out, and they generate large amounts of sediments which are generally disposed of in landfills. The research conducted so far to avoid landfill disposal has evaluated the utilization of dredged sediments for the manufacture and production of lightweight aggregates, Portland cement clinker, concrete, and bricks as components for stabilised road-base as well as supplementary cementitious material in ordinary Portland-blended cements after a proper calcination treatment [84][85][86][87][88][89][90][91][92][93][94][95][96][97][98].…”

Estimation of Silting Evolution in the Camastra Reservoir and Proposals for Sediment Recovery

“…Therefore, it is possible to develop a reuse application that does not fulfil structural functions. In contrast, for applications with structural functions, sandy material constituting fine aggregate could be submitted to an in situ washing pretreatment to make it clean and free of the smallest parts to guarantee higher mechanical strength [49]. In addition, according to this proposed reuse application, the advantages lie in the possibility of using large quantities of dredged sediment and reducing the use of virgin materials to manufacture conglomerates.…”