Use of shells for the mechanical stabilisation of sediments

This project on the mechanical stabilisation of fine marine sediments from Port of Taranto (Italy) explores novel eco-friendly solutions. The main idea of this research is to combine the two waste materials (marine sediments and mussel shell powder) with cement binders to produce a new stable material that can potentially be used in construction. What are the chemical and physical interactions affecting mechanical behaviour of such mixtures? Can the mussel shell powder partially replace cement without compromising useful geomechanical and geochemical properties of the stabilized sediments? Can such stabilized sediments still be modelled as soils when it comes to their geotechnical design and analysis? The research answers all these questions by assessing mechanical performance of the mixtures formed by sediments stabilised with three types of cement (one traditional type and two “green” types) and a mussel shell powder, and comparing it with that of the same sediments when treated with cement only and cured up from 7 to 28 days. Multiple beneficial effects of the use of mussel shell powder have been demonstrated: it acts as a void filler, enhances the electrolytic exchanges between sediment and cement, and increases the contact area between the mineral particles promoting the chemical hydration reactions. As a result, it enhanced geomechanical and geochemical performance of cemented marine sediments, which after treatment still exhibited soil-like behaviour consistent with traditional geomechanics. While limited at this stage to one particular type of marine sediment, this research demonstrates significant potential of using mussel shell powder as a partial replacement of cement in sediment stabilization.