How to Prevent Expanston of MSWI Bittom Ash in Road Constructions

Abstract Since the late seventies substantial effort has been put into searching for structural applications for bottom ash originating from the incineration of municipal solid waste (MSWI). Processing the MSWI bottom ash into cement-treated base courses (CTBC) appeared to be an attractive application to handle the large amount of bottom ash. As a result, several hundreds of thousands of tonnes of MSWI bottom ash have been applied in CTBC. However, in asphalt pavements, with a base course containing cementtreated MSWI bottom ash, sometimes the surface shows unevenness, because of local expansions occurring in the MSWI bottom ash. Therefore, an investigation into the expansion of asphalt pavements has been carried out. The first results of the research lead to the theory that particles of aluminium in the MSWI bottom ash cause the CTBC to expand. On the basis of this theory, several parameters which might affect the occurrence of local expansions in the bottom ash have been defined