Soil contamination by radioactive substances represents a major challenge in terms of public health and environmental protection. Among the various strategies considered for managing such polluted soils, the excavation of contaminated materials offers a pathway to the safe reuse of the site. The excavated soils, when characterized by low to intermediate activity and short-lived radionuclides, must be stabilized prior to disposal. In this context, cementation is widely used due to its moderate cost, ease of implementation, and capacity to confine numerous pollutants. However, its application to soils rich in swelling clays presents two major limitations: poor workability of the fresh material and volumetric instability of the hardened product. To address these issues, this thesis aims to evaluate the potential of magnesium silicate cements as an alternative to conventional calcium silicate cements. These emerging binders are currently attracting growing interest, particularly in the fields of earthen construction and the development of low-carbon materials.
The first objective will be to study the influence of various formulation parameters on the reactivity and properties of magnesium silicate cements. This will be followed by an in-depth investigation of the interactions between the cement phases and the main constituents of contaminated soils. Finally, the long-term durability of the formulated materials will be assessed through leaching tests, which will serve as input for reactive transport modelling, with the aim of gaining a better understanding of the degradation mechanisms and the long-term behaviour of the materials.
This research project is intended for a PhD candidate interested in advancing his/her expertise in materials physical chemistry and contributing to the development of innovative solutions for contaminated soil management and low-impact binder technologies.