This work forms part of the DTI/WRAP sponsored Aggregates Research Programme to support the development of construction markets for secondary and recycled aggregates. The report reviews the use of secondary and recycled aggregates in highway infrastructure, within the context of the Specification for Highway Works (SHW), with the emphasis on high-value applications in road construction. An examination of international experiences has been carried out to highlight the innovative research, techniques and programmes that could be introduced to the UK. The availability of secondary and recycled materials is discussed in terms of arisings, stockpiles and locations. Informal consultations with materials producers were carried out to identify existing and potential markets and barriers. A number of materials have been identified for which use could be extended to higher-value applications. These include construction and demolition wastes, incinerator bottom ash, glass, plastic, and tyre rubber as alternative aggregates. There is a potential for developing new applications of hydraulic bound materials and roller-compacted concrete using fly ash and slag. Assessment of the technical, environmental, and regulatory barriers to the use of the new materials/applications is discussed. The report also discusses material lifetime within the context of whole life costing, considering the economic cost of alternative materials, material performance and the potential for future recycling. Finally, the report concludes with a comprehensive set of recommendations highlighting the need for future work to overcome the barriers identified and to support the development of new materials in high-value applications in highway infrastructure. (Author/publisher)
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