Comparative study of stabilization/solidification of dredged sediments with ordinary Portland cement and calcium sulfo-aluminate cement in the framework of valorization in road construction material

Stabilization/solidification (S/S) of dredged sediments is an environmentally friendly, low-cost and time-efficient way to manage this waste (according to the European waste classification) in the context of valorization as novel resources. In this study, the main objective was to evaluate the efficiency of using a novel and green binder Calcium Sulfo-Aluminate (CSA) cement to solidified Dunkirk sediments. For comparison, the Ordinary Portland Cement (OPC) binder was used as a reference. For this purpose, several tests were performed on samples containing various types and amounts of binders. The experimental program included: modified Proctor compaction tests, immediate Californian Bearing Ratio (I-CBR) index tests, unconfined compressive strength tests, splitting tensile strength tests, measurements of elastic and secant modulus, and mineral and micropore structure analysis. It is realistic to conclude that the compaction performance of the CSA-/OPC-solidified sediments is significantly improves. The mechanical performance of compressive, tensile strength and elastic modulus increases with binder content and curing time. The simple model obtained to relate the compressive and tensile strength with elastic modulus allows predicting easily, for a given suitable set of characteristics, the type or the amount of binder needed. This model allows optimizing the amount of binder to reach a given properties of solidified sediments and hence improves the cost of developed material. The results also demonstrate the ability of solidified sediment to be valorized in road construction.