Abstract

This study focuses on geopolymers produced from Municipal Solid Waste Incineration ashes, in order to transform ultimate and hazardous waste containing heavy metals into a chemically stable and economically competitive construction product. The main objective of the study is to evaluate the efficiency of the toxic elements immobilization after heat treatment. Samples were prepared with different proportions of fly ash, bottom ash and waste glass by activation with an alkaline solution. Waste glass was used to improve certain physical properties and decrease possible leaching. Incinerator waste-based geopolymers were observed and analyzed by X-Ray Diffraction and by Scanning Electron Microscopy coupled with Energy Dispersive X-ray microanalysis. The sustainability of these waste-bearing geopolymer materials has been constrained through leaching experiments (TCLP), density, porosity and water absorption measurements. The important result is that heat treatment appears to decrease both porosity and water absorption of geopolymers, thus resulting in a strengthening of waste-bearing matrices. The effect of heat treatment on leaching behavior was more difficult to identify, as discussed below. Furthermore, we observe that replacing a portion of FA and BA by waste glass significantly increases both physical and chemical resistance of geopolymers, probably due to pore filling by melted waste glass.