There is a need for engineers, particularly client engineers, to understand the full implications of using reclaimed and secondary materials. Whilst efforts to make highway construction more sustainable are laudable, they must be effective over the longer-term and not be just reduced cost and/or environmental impact on the construction phase alone. If the use of such components in the mixtures does affect the serviceability or durability of the mixture, then any savings may be transitory.

The project will build upon existing knowledge, supplemented by limited site and laboratory studies, to develop a specific model to look at this issue and to provide indicatory values for use in the model. The existing knowledge will be extended with an extensive literature search on the times for construction and the relevant effects that determine the service lifetime of the different pavement layers. The site trials will look at mixtures with and without reclaimed asphalt, but will have to assess their durability from early-life properties. The laboratory trials will concentrate on combined effect of ageing and moisture damage on the performance of selected asphalt mixtures containing different proportions of reclaimed asphalt. All three strands will be fed into life-cycle analysis models to customise them for the effect of using alternative component materials on the availability of the network and their overall financial and environmental cost.



TRL Limited, UK (Co-ordinator)
Cliff Nicholls

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University of Kassel, Germany
Konrad Mollenhauer

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University College Dublin, Ireland
Amanda Gibney

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Technische Universiteit Delft, Netherlands
Katerina Varveri

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Lagan Asphalt, Ireland
Sean Cassidy

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Shell Bitumen, UK / Germany
Richard Taylor

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Work Packages

Service lifetime and availability of road materials and structures, review of existing data - WP leader: UoK
Site trials evaluating varying proportions of reclaimed asphalt - WP leader: UCD
Experimental evaluation of moisture damage and ageing in asphalt mixtures - WP leader: TUD
Impact assessment modelling - WP leader: TRL
Project coordination and knowledge dissemination - WP leader: TRL


1 January 2013 to 31 December 2014


Published Outputs

Final Workshop Presentations

The project concluded with an international workshop on ‘Recycling: Road construction in a post-fossil fuel society’ held in Prague on 24th-25th September 2015. Four presentations were delivered by the EARN project team: P1: EARN background data (C Nicholls on behalf of K Mollenhauer), P2: EARN site trial (S Cassidy), P3: Laboratory Testing for EARN (K Varveri) and P4: Modelling for EARN (M Wayman). EARN was presented alongside the two other projects commissioned under the same research theme: CoRePaSol and AllBack2Pave.

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