Technical feasibility for the replacement of high rates of natural aggregates in asphalt mixtures

ABSTRACT

This research demonstrates the technical feasibility of replacing new raw materials by recycled and renewable alternative ones to make different sustainable asphalt mixes. In order to verify performance, a comparative analysis of different alternative materials was carried out. Electric arc furnace (EAF) slag, basic oxygen furnace (BOF) slag, waste foundry sand and reclaimed asphalt pavement (RAP) were used to replace natural aggregates in different proportions to enable the impact on asphalt concrete to be studied. Moreover, with the aim of restoring the properties of old binder from RAP and maximising the reduction in the amount of virgin binder needed, the effect of two rejuvenators was evaluated. The technical feasibility of using asphalt mixtures with a natural aggregate replacement rate of 80–98% was demonstrated at laboratory level. In this sense, the use of EAF and BOF slag to replace high-quality natural aggregate in the coarse fraction and the use of waste foundry sand to replace natural aggregate in the fine fraction proved to be a promising option. Furthermore, a significant virgin binder reduction was achieved with the combined use of RAP and rejuvenator, without compromising the mechanical performance of the mixtures.

KEYWORDS:

• Asphalt
• recycled materials
• Reclaimed asphalt pavement
• by-products
• rejuvenator

Acknowledgements

This study is framed within the ALTERPAVE project. This project was carried out by a consortium coordinated by GITECO (Construction Technology Applied Research Group, University of Cantabria) and integrated by ACCIONA Infrastructuras (Spain), I. Bacchi (Italy), Statens väg- och transportforskningsinstitut VTI (Sweden) and Western Research Institute (USA). The authors wish to acknowledge and especially thank Emilio Blas Galindo (ACCIONA), Matteo Bacchi (I. Bacchi), Livio Trussardi (I. Bacchi), Dina Kuttah (VTI) and Jean-Pascal Planche (WRI) for their collaboration.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

ALTERPAVE is co-funded by Funding Partners of the ERA-NET Plus Infravation and the European Commission. The Funding Partners of the Infravation 2014 Call are: Ministerie van Infrastructuur en Milieu, Rijkswaterstaat, Bundesministerium für Verkehr, Bau und Stadtentwicklung, Danish Road Directorate, Statens Vegvesen Vegdirektoratet, Trafickverket-TRV, Vegagerdin, Ministere de l’Ecologie du Developpement Durable et de l’Energie, Centro para el Desarrollo Tecnológico Industrial, Anas S.P.S, Netivei Israel – National Transport Infrastructure Company LTD and Federal Highway Administration USDOT. This work was supported by the European Union’s Seventh Framework Programme for research, technological development and demonstration [grant numbers 1109806.0006]; and the FPU Programme of the Ministerio de Educación, Cultura y Deporte (Spain) [grant number FPU-14/06997].