Lookup NU author(s): Dr Oliver Heidrich,
Dr Yongjian Huang
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Large amounts of virgin aggregates are quarried every year from UK land sources, of which large majority is being used in the construction industry. The UK road industry requires a substantial amount of asphalt (some 30 Mt per year), which is made more than 90% with aggregates. It is not clear how much of this can be made from recycled materials and the level of recycling in asphalt pavements does vary across the world and the UK, which seems mainly due to the difference of access to suitable natural aggregates and recycled aggregates. In total some 335 million tonnes per annum of solid waste are created in the UK. Only a small fraction (less than 2 million tonnes) is being recycled in asphalt pavements. The aim of this paper is to provide an overview of the technical and managerial issues that are associated with the recycling of such waste in pavement applications. This will be achieved by briefly summarising the UK quarrying, waste generation situation. This will be followed by the technical requirements for asphalt roads as any road, using virgin or recycled materials have to fulfil such requirements. Waste glass, steel slag, tyres and plastics are being described considering the waste generated in the UK, the technical requirements and the findings of previous are being reported. The suitability of the materials investigated here, namely glass, steel slag, tyres and plastics do depend on various factors such as: mixture types (different mixtures (e.g. SMA, HRA) impose different property requirements for component aggregates); particle size of recycled waste types and replacement rate; and the nature and processing techniques for the waste types (e.g. weathering for steel slag). The paper concludes that the selection of suitable materials, regardless of its origin, and in particular for aggregates sourced from waste materials does depend on a range of factors. Such factors may differ substantially depending on the pavement requirements as well as the waste material, the later and its associated factors are being described in more detail in this paper.
Author(s): Heidrich O, Bird RN, Huang Y
Publication type: Conference Proceedings (inc. Abstract)
Conference Name: ISWA/NVRD World Congress 2007: Challenging the Future
Year of Conference: 2007