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Today, 900 tons incineration fly ash is shipped abroad annually from Greenland for deposits, whereas the 6,000 tons incineration bottom ash is deposited locally. These incineration ashes could be valuable in concrete production, where the cement has to be shipped to Greenland. For this purpose, the effects on compressive strengths of mortars by substituting cement or sand by raw, washed and electrodialytically treated fly ash or bottom ash were investigated.
Parts of the experimental fly ash had been pre-treated by either washing with distilled water or electro-dialytically treated to remove salts and by the latter method, also heavy metals. Mortar samples were cast where cement (5%–20%) or sand (5%–10%) was replaced with fly ash or bottom ash, together with references without replacements. The compressive strengths were measured after 7, 14, 28 and 42 days. Replacing cement by fly ash resulted in lower compressive strength at 20% content of fly ash. At 5% replacement with raw fly ash a compressive strength similar to the reference was seen. However, using washed and electrodialytically treated ash lead to lower strengths. The lowest compressive strength was seen when replacing both sand with bottom ash and cement with fly ash.
Based on the compressive strength tests, it is found that using Greenlandic incineration ashes in mortar as 5% cement replacement could consume all ash instead of disposals, and could thus turn the ashes into a local resource and simultaneously reduce the import of cement.
arctic, bottom ash, colour, compressive strength, concrete, electrokinetic, fly ash, mortar, setting time, washing
[1] Kirkelund, G.M., Geiker, M.R. & Jensen, P.E., Electrodialytically treated MSWI APC residue as substitute for cement in mortar. Nordic Concrete Research, 49(1), pp. 1–16, 2014.
[2] Ottosen, L.M., Jensen, P.E., Goltermann, P. & Kirkelund, G.M., Sewage sludge ash as cement replacement after simple pretreatment. Proceedings Sardinia 2013, Fourteenth International Waste Management and Landfill Symposium.
[3] Goltermann, P., Ottosen, L., Jensen, P.E. & Kirkelund, G.M., ZeroWaste: turning waste into a new, sustainable resource for concrete. Proceedings of the XXII Nordic Concrete Research Symposium, Reykjavik, Iceland, pp. 233–236, 2014, ISBN 978-82-8208-043-9.
[4] Kirkelund, G.M., Jensen, P.E. & Ottosen, L.M., Electrodialytic extraction of heavy metals from Greenlandic MSWI fly ash as a function of remediation time and L/S ratio. Proceedings of the 10th International Symposium on Cold Regions Development, pp. 87–96, 2013. http://dx.doi.org/10.1061/9780784412978.009
[5] Jensen, P.E., Ferreira, C.M.D., Hansen, H.K., Rype, J.U., Ottosen, L.M. & Villumsen, A., Electroremediation of air pollution control residues in a continuous reactor. Journal of Applied Electrochemistry, 40(6), pp. 1173–1181, 2010. http://dx.doi.org/10.1007/s10800-010-0090-1
[6] Kirkelund, G.M. & Jensen, P.E., Electrodialytic treatment of municipal solid waste incineration fly ash – removal of heavy metals and evaluation of matrix changes for reuse. In Preparation.
[7] DS 259, Determination of metals in water, sludge and sediments – General guidelines for determination by atomic absorption spectrophotometry in flame, 2003.
[8] DS/EN 196-1, Methods of testing cement – Part 1: Determination of strength, 2005.
[9] DS/EN 196-3, Methods of testing cement – Part 3: Determination of setting times and soundness, 2009.
[10] Kosmatka, S.H., Kerkhoff, B. & Panarese, W.C. (eds), Design and Control of Concrete Mixtures, EB001 14th edn., Portland Cement Association: Skokie, Illinois, USA, 2002.
[11] DS/EN 450-1, Fly ash for concrete – Part 1: Definition, specifications and conformity criteria, 2007.
[12] Lima, A.T., Ottosen, L.M. & Ribeiro, A.B., Assessing fly ash treatment: remediation and stabilization of heavy metals. Journal of Environmental Management, 95, pp. S110–S115, 2012.
[13] Geiker, M.R., Kjeldsen, A.M., Galluci, E. & Bager, D.H., Preliminary investigation of the effect of air-pollution-control residue from waste incineration on the properties of cement paste and mortar. Proceedings for Advances in Cement and Concrete X, Davos, Switzerland, 2006.
[14] Chen, C.G., Sun, C.J., Gau, S.H., Wu, C.W. & Chen, Y.L., The effects of the mechanical-chemical stabilization process for municipal solid waste incineration fly ash on the chemical reactions in cement paste. Waste Management, 33, pp. 858–865, 2013. http://dx.doi.org/10.1016/j.wasman.2012.12.014
[15] Kappel, A., Ottosen, L.M., Kirkelund, G.M., Bache, A. & Goltermann, P., The colour potentials of SSA-containing mortar. Proceedings for Concrete – Innovation and Design, fib Symposium, Copenhagen, Denmark, pp. 18–20, 2015.