Optimal Recycling of Reclaimed

Asphalt Pavements


A project financed by the European Union within the framework of INTERREG

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Main issues

The Upper Rhine region has a densely populated and busy regional road network, which requires large quantities of noble materials such as aggregates or bitumen from petroleum refining. These materials are used in the composition of various asphalts.
In addition to the unbonded layers of the layers linked to the various functions and lifetimes, the road construction thus has to be partially or completely milled during maintenance measurements, resulting in the production of large quantities of asphalt aggregates (AA) (some tens of thousands of tons).

These AAs must be recycled in Germany, France and Switzerland in the most efficient way possible, which on the one hand saves non-renewable resources, aggregates and bitumen and on the other hand reduces the environmental impact The production of these resources, their transport and storage. This also reduces storage costs. At present, reuse of AA is carried out either in the manufacture of asphalt (with an operating temperature of 160°C or 130°C. around which ensures good maneuverability of the material) or in cold mixtures, during which bitumen emulsions ( Regenerating) or cement (called "binder") are added. Use in binder-free layers in Germany is permitted up to a maximum of 30% of AA.

By using AAs without the addition of bituminous binder and at room temperature, the current AA recycling rate would be greatly increased, environmental impacts would be minimized (CO2 emissions, energy consumption and natural resources) and road maintenance costs would be Reduced. Thus, significant ecological and economic gains could be realized for the management bodies of low-traffic communal roads, which account for about 50% of the road network in the Upper Rhine region.

Aims and Objectives

Within the framework of the project an intense exchange of experience must take place between the concerned countries of the Upper Rhine on the way in which the AAs have been considered up to now. A new strategy for the recycling of AAs without the addition of bituminous binders at ambient temperature for low traffic pavements in the Upper Rhine region will be developed.
The objectives of this strategy are to increase the recycling rates of AAs, to limit the negative impacts on the environment (CO2 emissions, energy consumption, consumption of fossil resources, production of bituminous concrete waste, PAH) and reducing road maintenance costs. In this way, bituminous concretes already containing high AA contents or which because of the numerous measurements of rehabilitation have a nonhomogeneous composition can be recycled optimally.

The main steps of the project are:
-Identification and analysis of AA recycling practices and techniques
-Development of a new AA recycling strategy
: The objective here is to achieve an optimum formulation of the granular mixtures entirely composed of AA to be used as a base layer or a self-leveling surface, taking into account the mechanical, thermal and hydraulic properties of the mixture. We will study AAs from recycling centers: homogeneous, or not (mixtures),Containing PAHs or not.
-Evaluation of the economic and environmental impact
-Implementation of this technique in our respective regions will be studied both from an economic and environmental point of view. A risk analysis will be conducted for the three countries and will concern the human being and the environment (PAH, asbestos).
-Formulation and provision of recommendations applicable by the practitioners.


Institutes of Education and Research









  • Institutes of education and research:

- National Institute of Applied Sciences (INSA)

of Strasbourg - FR


- Hochschule Karlsruhe - DE 

- University of Applied Sciences

and Arts Northwestern Switzerland (FHNW) - CH 

- Swiss Federal Laboratories for Materials Science

and Technology (EMPA) - CH

  • Comunities:

- Canton Bâle-Campagne - CH

- Canton d’Argovie - CH

- Confédération suisse - CH


  • Institutions:

- Bundesanstalt für Straßenwesen - DE

- Deutsches Asphaltinstitut (DAI) - DE

  • Comunities:  

- Département du Haut-Rhin - FR

- Département du Bas-Rhin - FR

- Regionalverband Mittlerer Oberrhein - DE

- Stadt Karlsruhe - DE

- Landkreis Karlsruhe - DE

  • Companies:

- Colas Est - FR

- LABINFRA (Groupe Hydro-géotechnique) - FR

- Société Alsacienne de Recyclage des Matériaux - FR

- Südwest Asphalt GmbH & Co KG - DE

- Ziegler AG - Bauunternehmung - CH




PhD. defense: Laura Gaillard - 15/11/2019 (for more information, in French: link INSA - link UNISTRA)

Tenth General Meeting - 16/10/2019 - Hochschule Karlsruhe

Ninth General Meeting - 18/06/2019 - INSA de Strasbourg 

Eighth General Meeting - 27/02/2019 - Cerema, Strasbourg

Second Annual Meeting - 19/10/2018 - Hochschule Karlsruhe

ORRAP Final Annual Meeting - 02/12/2020 - Online Event


Sixth General Meeting - 27/06/2018 - EMPA, Zürich

Fifth General Meeting - 21/02/2018 - INSA de Strasbourg


Annual Meeting - 26/10/2017 - Fachhochschule Nordwestschweiz, Basel




Third General Meeting - 05/07/2017 - Hochschule Karlsruhe

Second General Meeting - 30/03/2017 - INSA de Strasbourg

Kick-off Meeting - 02/12/2016 -  INSA de Strasbourg

Pre kick-off Meeting - 05/10/2016 - INSA de Strasbourg


Annual meeting.JPG

ORRAP Executive Summary

ORRAP Executive Summary 2


Report - Action 1.1 (German version)

General Presentation - Workplan 

Report - Action 1.2 (German version)


PhD thesis

Conference articles:

Consideration of CO2-emissions in Pavement Management
A. Brzuska B. Eng.; Dr. rer. pol. S. Cypra; Prof. Dr.-Ing. C. Holldorb; Prof. Dr.-Ing. M. Stöckner, Karlsruhe, Straße und Autobahn 10/2018

Journées Technique routes
Mercredi 6 février 2019
Recyclage optimal des agrégats de béton bitumineux dans les chaussées à faible trafic (ORRAP)

Energie- und Materialflüsse im Straßenbau
CYPRA, SONJA; HOLLDORB, CHRISTIAN, in: Seminarband zum 1. Kolloquium Straßenbau in der Praxis am 29.01 und 30.01.2019 in Ostfildern/Stuttgart Technische Akademie Esslingen


Study of the Mechanical Behaviour of Reclaimed Asphalt Aggregates Without Binder Addition

Laura Gaillard, Cyrille Chazallon, Pierre Hornych and Juan Carlos Quezada,7th International Symposium on Deformation Characteristics of Geomaterials Strathclyde's Technology & Innovation Centre, Glasgow, UK26th – 28th June 2019

Journal articles:

Thermo-hydro-mechanical Behaviour of Cold Reclaimed Asphalt Aggregates Without Binder Addition
Laura Gaillard, Cyrille Chazallon, Pierre Hornych, Juan Carlos Quezada & Christiane Raab
Pages S49-S63 | doi.org/10.1080/14680629.2019.158749, Journal Road Materials and Pavement Design
Volume 20, 2019.



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