Publication: Thermal and Fatigue Evaluation of Asphalt Mixtures Containing RAP Treated with a Bio-Agent

Kowalski K. J., Król J. B., Bańkowski W., Radziszewski P., Sarnowski M., Thermal and Fatigue Evaluation of Asphalt Mixtures Containing RAP Treated with a Bio-Agent,  Applied Sciences, vol. 7, no. 3: 216, 2017.

Special issue: Advanced Asphalt Materials and Paving Technologies.

DOI: 10.3390/app7030216


Environment conservation and diminishing natural resources caused an increase in popularity of the application of renewable bio-origin resources for the construction of road pavement. Currently, there are known additions of bio-origin materials for bitumen modification. Such material is also used as a flux additive for bitumen or as a rejuvenator once working with reclaimed asphalt pavement (RAP). This paper presents research dealing with asphalt mixtures with RAP modified with a bio-agent of rapeseed origin. The main idea of the conducted research was to apply more RAP content directly to the batch mix plant without extra RAP heating. The RAP used in this study was milled from a base asphalt layer; the addition of RAP stiffens new asphalt mixtures. A bio-agent, due to its fluxing action, was used to support the asphalt mixing process and to decrease the over-stiffening of the mixture caused by RAP addition. This research includes bitumen and mixture tests. For the bitumen study, three different bitumens (35/50, 50/70, and 70/100) were tested in a dynamic shear rheometer (DSR) for complex modulus G* and for phase angle |δ| in the temperature range 0–100 °C. The reference mixture and mixtures with 2.5% bio-agent were tested to assess the influence of RAP and the bio-agent addition on the asphalt mixture properties. Low temperature behavior (TSRST), stiffness, and fatigue resistance (4PB) were tested. Based on the bitumen test, it was determined that even a low rate of bio-agent (2.5%) beneficially changes bitumen properties at a low temperature; moreover, polymerization processes occurring in the second stage of the process improves bitumen properties at a high operational temperature. The research with these asphalt mixtures demonstrates that the bio-origin flux acts as a rejuvenator and allows for an application of 30% cold RAP. Thermal cracking resistance of the mixture with RAP and 2.5% bio-agent improved. The bio-agent removes unfavorable stiffening of RAP and increases the fatigue resistance of the asphalt mixture. View Full-Text


Keywords: bioadditive; reclaim asphalt pavement (RAP); warm mix asphalt (WMA); sustainable roads

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For more information:


Around 2000 km of roads built by our company in the past decade are evidence of our dedication to innovation. We construct projects on the basis of firm sustainability, environmental and social criteria, introducing new and better construction processes applying more measures to protect the environment. The photo shows one of the highways we have constructed in Spain, emerging from Azpiroz tunnel


ACCIONA, JEC World 2016 Award for the first lighthouse made from composites in the world

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   Cuenca footbridgeAlmuñecar footbridgebiobuild external wallPRESS-LD-03 faro-composites-01  PRESS-LD-05

WUT is looking for new partners

We are looking for partners from countries which are eligible to receive funding through Horizon 2020 grants – we want to apply with you!

Warsaw University of Technology,

Faculty of Civil Engineering

Institute of Roads and Bridges

Road Materials and Technology Division


is involved in projects concerning road construction and sustainable development.

We are looking for new partners to work on projects related to APSE project, materials and road technology.

We have experience in various European projects (e.g. FP7 and Horizon 2020) so we can cooperate or lead project.

If you have any questions, ideas or if you want to cooperate with us please let us know:

Karol Kowalski
v-ce Director of Institute of Roads and Bridges

APSE Project Manager in WUT