Evaluation of the Potential Expansion Mechanisms of Bottom Ash in Unbound Sub-base Materials

  • Padraic Mac Giolla Bhride

    Student thesis: Master's ThesisMaster of Science


    The aim of this dissertation is to evaluate the potential for bottom ash from the incineration of municipal solid waste to undergo chemical reactions which could lead to expansion when used as an unbound granular fill
    This paper sets out the experimental results obtained from testing of the Incinerator Bottom Ash under several procedures. A literature review was carried out to determine the common characteristics of bottom ash, from the literature review a series of tests were chosen to characterise certain properties of the material.
    Several mix proportions of IBA and chemical additions of sodium sulphate (Na2SO4), sodium hydroxide (NaOH) and Calcium Chloride (CaCl2) were made to hasten chemical reactions. Several standard tests and new hybrid tests were performed to determine the properties of the mix proportions. Tests such as rapid evaluation of expansion, X-Ray diffraction, X-Ray fluorescence, pH testing, microscopic examination, magnetic separation analysis, Thermogravimetry, Scanning Electron Microscopy and accelerated chemical reactions.
    Results showed that expansion appears to be through two mechanisms, unpredictable relaxation of compacted material and more notably the formation of expansive gels promoted by alkaline conditions.
    Date of Award2015
    Original languageEnglish
    SupervisorThomas Dyer (Supervisor)

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