The recycling of bituminous basecourses and roadbases has the potential to save energy and natural resources and to reduce the cost of major maintenance. These savings can only be realised if a pavement containing recycled material performs as well as one produced conventionally. In this report two trials are described; the first is a pilot-scale trial and the second is a full-scale trial on a trunk road. The recycled materials were compared to virgin materials in performance-related laboratory tests and the in-service performance was assessed in the full-scale trial. The cost of production and energy usage during construction were determined. The trials demonstrated that recycled material can comply with the relevant specifications when it is produced using modified drum-mixers and laid using conventional plant. The in-service performance of a pavement containing up to 60 per cent recycled material was as good as one constructed with conventional material. Cost savings of up to 30 per cent can be made when recycling at 60 per cent. Energy savings are worthwhile but contribute only a small part to the cost savings. (Author/publisher).
Abstract