HOW TO PREVENT EXPANSION OF MSWI BOTTOM ASH IN ROAD CONSTRUCTIONS ?

This paper discusses research carried out to investigate unevenness in asphalt pavements caused by expansion of the cement treated basecourses that contain municipal solid waste incinerator (MSWI) bottom ash. The objective of the research was (1) to understand the formation of the expansion and (2) to give guidelines to prevent this problem. The investigations focussed on the reaction of non-ferrous metallics in the MSWI bottom ash, particularly aluminium, under alkaline conditions. The effect of the following parameters on the expansion were investigated: a) the incineration plant from which the MSWI bottom ash originated; b) the composition of the cement mixture; c) the kind of cement used; and d) the conditions during storage of the ash. Based on the research results a theory is formulated, explaining that the aluminium is oxidized in the cement bound MSWI bottom ash resulting in the formation of soluble aluminate ions. The aluminate will be converted into aluminium hydroxide, which causes an increase in volume. Guidelines to prevent expansion are given with respect to: a) the quality of the MSWI bottom ash supplied; b) the conditions during storage of the ash; and c) the conditions in the basecourse layer. The latter appears to have a significant effect on the formation of expansions. For the covering abstract of the conference see IRRD 869363.

Language

  • English

Media Info

  • Features: References;
  • Pagination: p. 863-76

Subject/Index Terms

Filing Info

  • Accession Number: 00675815
  • Record Type: Publication
  • Source Agency: DIENST WEG- EN WATERBOUWKUNDE (DWW)
  • ISBN: 0-444-81853-7
  • Files: ITRD
  • Created Date: Apr 12 1995 12:00AM