Large amounts of material will be needed to install covers on closed landfill constructions due to the application of EU landfill directive 1999/31/EC. Approximately 1 million Mg of ashes are produced in Sweden every year. The interest in substituting conventional construction materials for landfill covers by alternative materials increases by the possibility to implement advantages, such as saving natural resources and economic benefits, using secondary construction materials (SCM). However, to use SCM for the intended purpose advantageously, new challenges compared to the use of conventional materials have to be solved, such as material availability, storing, preparation, planning and the construction process itself. Field tests with different alternative cover construction designs have been performed at the Tveta Landfill in Södertälje since 2003. During an excavation in summer 2007 samples had been taken from the different layers of the cover of two test fields. The results of the analyses show that the construction process itself influences the mechanical and chemical properties of the cover construction. Also, a trend to decreasing concentrations for most of the concerned components within the materials could be seen. An important result of this study is that SCM can fulfil the legal requirements in Sweden for landfill cover constructions. Whether constructing with SCM is successful or not strongly depends on anticipatory planning, the design of the cover construction, the knowledge of the properties of the materials and both, their development over time and their interactions.
closed landfill – alternative landfill cover constructions – utilization of combustion residues – fly ash – bottom ash – recycling construction materials – secondary construction materials – landfill, depositing – leaching – ageing
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