Highly Recycled Asphalt Pavement (HighRAP)



The objective of the HighRAP project was to develop recommendations that would allow increasing the average reclaimed asphalt content in asphalt production without compromising the pavement performance.

Duration: 04.07.2019-31.12.2022


Project Summary

The project addressed three main research topics:

1) RAP Materials

2) Mix design

3) Performance

Within these topics, individual studies addressed the characterization of RAP, improvement of RAP crushing and screening, aging and rejuvenator selection, performance-based mixture design, and construction of two test sites with high RAP content: one in a high traffic road and one at high altitude (1,900 m above sea level).


Project Activities

The HighRAP project tasks and activities for each of the three research directions are shortly summarized below.




Activities during HighRAP project

RAP milling & processing

Develop RAP processing procedures that allow maximizing the RAP use in production.

  • A full-scale experiment to evaluate the effect of milling.
  • A full-scale experiment to develop a method for quantitative assessment of RAP crushing and screening procedure.

RAP characterization

Develop simplified test methods for rapid RAP characterization without extracting binder.

  • A full-scale experiment to evaluate the suitability of two methods for characterization of RAP without extraction of binder.

Aging & Rejuvenators

Develop an aging protocol for mixture design to assess durability of rejuvenated RAP.

  • Laboratory-aging of asphalt to compare with plant produced mixes and road cores.
  • Development of a procedure for evaluation of rejuvenator aging resistance.

Performance-based mix design

Develop of a procedure that would allow designing high RAP mixtures with similar performance and life cycle to the conventional asphalt.

  • Use a performance-based mixture to design the mixtures for test sections.
  • Develop acceptance criteria for semi-circular bend and cyclic compression tests. 

Test section in Uster

Evaluate full-scale production and paving of high RAP mixtures for high traffic roads.

  • Construction of a test section in Uster to validate the performance of polymer-modified mixtures with high RAP content.

Test section in Lukmanierpass

Evaluate full-scale production and paving of high RAP mixtures for high altitude roads.

  • Construction of a test section in Lukmanierpass to validate the performance of foundation and base course mixtures with high RAP content.



Construction of test section on Lukmanierpass. 


Construction of test section in Uster. 
Principles of performance-based mix design
Three principles of asphalt recycling. 

Project Leader

Martins Zaumanis


Lily Poulikakos, Empa

Lukas Boesiger, Ammann Schweiz AG

Bernhard Kunz, BHZ AG

Henry Mazzoni, Catram AG

Peter Bruhin, Catram AG

Dominique Lötscher, Reproad AG

Urs Schellenberg, Kanton Zürich


Monitoring Committee


Fabian Traber, Bundesamt für Strassen (ASTRA)


David Hiltbrunner, Bundesamt Für Umwelt (BAFU)

Remo Fehr, Amt für Natur und Umwelt - Kanton Graubünden

Dominik Oetiker, Amt für Abfall, Wasser, Energie und Luft – Kanton Zürich

Christoph Gassmann, Baudirektion Kanton ZH Tiefbauamt

Nicolas Bueche, Bern University of Applied Sciences (BFH)