The Possible Use of Untreated Municipal Mass Burn Residues in Highway Subbase Construction

Abstract

Four samples of mass burn residues were collected from four different municipal facilities and examined to determine their structural suitability for highway subbase construction. One sample was bottom ash only, and the other three were mixtures of fly and bottom ash. Laboratory procedures were used to determine the following; water content, particle size distribution, physical description, moisture-density relationships, loss on ignition, presence of organic impurities, and classification of each sample. A literature search was used to explore the environmental implications of residue use in subbase construction. Two of the samples appeared to be structurally acceptable for subbase material. One sample lacked an acceptable particle size distribution and had a very high loss on ignition value. The fourth sample had a high loss on ignition value and a high amount of organic impurity. Sound engineering practices during construction of a highway subbase can offer an acceptable degree of residue encapsulation, and use as subbase material could be a viable option for residue disposal or use.