On the degree of binder activity of reclaimed asphalt and degree of blending with recycling agents

Abstract

It is common practice to assume full blending of the aged binder of reclaimed asphalt (RA) within the design of new asphalt mixtures. Although being practical, this assumption has often led designers to asphalt mixtures lacking binder. Hence, going towards recycled asphalt mixtures (RAM) there is a need to have a better understanding of the blending phenomena, to have a general agreement on terminology and finally adapting RA classification and mix design procedures accordingly. This manuscript aims at being both a reference and stimulus for the scientific community to work in this direction and on this basis provides a nomenclature and a theoretical framework of the blending phenomena. The study is built upon a literature review on definitions, methods and influencing factors related with the blending phenomena and as a result, an intrinsic property of RA, the Degree of binder Activity (DoA), is introduced for the sake of improving RA classification. Furthermore, the two well-known concepts of the Degree of Blending (DoB) and the Degree of binder Availability (DoAv) are redefined, within the proposed framework, together with practical suggestions to introduce them in mix design procedures.

Keywords:

• degree of activity
• degree of blending
• degree of availability
• recycled asphalt
• recycling agent
• blending phenomena

Acknowledgments

The authors want to acknowledge the asphalt technologists of the RILEM Technical Committee 264 RAP for the fruitful discussions and feedback that have significantly enriched the paper. The third author is supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia through the research project TR 36017 “Utilization of by-products and recycled waste materials in concrete composites in the scope of sustainable construction development in Serbia: investigation and environmental assessment of possible applications” and this support is gratefully acknowledged. Furthermore, all authors would like to thank Ahmed Abed, University of Nottingham, for his valuable help.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Davide Lo Presti http://orcid.org/0000-0002-5125-8074

Kamilla Vasconcelos http://orcid.org/0000-0003-4305-4829

Marko Orešković http://orcid.org/0000-0001-8978-0354

Gustavo Menegusso Pires http://orcid.org/0000-0001-7918-8090

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

The fourth author is supported by Conselho Nacional de Desenvolvimento Científico e Tecnologico, CNPq – Brazil [grant number 200279/2014-9]. The third author is supported by the Ministry for Education, Science and Technology, Republic of Serbia through the research project TR 36017 ‘Utilization of by-products and recycled waste materials in concrete composites in the scope of sustainable construction development in Serbia: investigation and environmental assessment of possible applications’.