Material Characterization of Municipal Solid Waste Incinerator (MSWI) Ash As Road Construction Material

In the United States, bottom and fly ashes from waste-to-energy (WTE) plants are typically mixed together before the disposal into landfills to meet the U.S. Environmental Protection Agency (EPA) requirements. Conversely, in many Asian and European countries, the WTE fly ash is not mixed with bottom ash but rather handled as a special waste. In this instance, the bottom ash is often recycled and used as a material in pavement and other similar products. Reuse of the WTE ashes in Portland cement concrete (PCC) and hot-mix asphalt (HMA) may offer a significant contribution to reduce cost for waste disposal, natural resources conservation, and developing sustainable construction. An important factor hindering the acceptance of WTE ashes as construction materials, however, is their uncertain physical and chemical properties. In this study, fundamental properties of the WTE bottom and fly ashes were studied by conducting physical, microstructural, and chemical tests using a scanning electron microscope (SEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD).