Hydration of lime—marine sediment blends: Influence of mineralogical composition and lime content

There is a need to find alternatives to the extraction of non-renewable mineral resources for the production of new binders. Some specific building materials such as plant-aggregate-based concretes do not require high-strength binders. In this context, the lime-pozzolan technology, inherited from Roman times, can help reduce the carbon footprint of finished materials by the use of low amounts of lime. In this paper, three different marine dredged sediments were used as natural alumino-silicate resources and blended with hydrated lime. Based on previous literature dealing with the pozzolanic activity of cristallized minerals, the sediments were reduced to micronized powders. The hydration of these systems was investigated through hardening and reaction kinetics up to 365 days at 20 °C and 50 °C. The sediments used revealed two kinds of mineral assemblages and the best pozzolanic reactivity was found with quartz-rich sediments. In addition, the optimum lime content was found to be 20 wt% until 180 days.