Spreader Stoker thermal power plants located in Reunion Island bum bagasse during the sugarcane harvest and coal the rest of the season.Coal fly ashes released from this process are currently sent to landfill since they dont respect European Standard EN 450-1 and French Ministerial Decree of 28 October 2010.In fact, they cannot be used in civil engineering applications due to unburned carbon content higher than the one recommended in the European Standard EN 450-1 and cannot be considered as inert waste because of leachate concentrations which dont meet regulatory guidelines recommended in the French Ministerial Decree of 28 October 2010.From an economical and environmental point of view, the landfill of these ashes is a serious concern and an alternative solution consisting in reusing them appears to be essential.For example, these fly ashes could be incorporated in hydraulic binders for the manufacturing of nonstructural blocks.A previous study reported encouraging mechanical and leaching results for fly ash/cement and fly ash/cement/slag systems.The use of cement and/or slag decreases the release of dangerous elements (oxyanionic and metal species) but some leachate concentrations are still too high.These mixtures dont represent the best stabilization solution and more research work is needed to find other alternative solutions, which neutralize all dangerous elements.