Efficient asphalt pavement technologies by combination of increased reclaimed asphalt content and warm mix solutions – effect on workability and cracking

Abstract

The ongoing discussion spanning over 20 years in Europe, along with continuous development of solutions and
additives, has led to warm mix asphalts (WMA). In reality, applications lag significantly behind the progress made
in the USA in last 10 years. Nevertheless, the road administrations begin to understand the potential, presented
mainly by the combination of WMA concepts with an increased use of reclaimed asphalt material from
rehabilitated roads. If reclaimed asphalt is treated at a lower working temperature and, moreover, additional
techniques or additives are capable of improving the added value delivered by reclaimed material in new asphalt,
the result is not only energy savings but also an increased contribution to circular economy at the same time.
In this respect, several trial sections were defined, funded and completed in the Czech Republic with a focus on
comparing different WMA solutions in combination with reclaimed asphalt contents of over 30 % for the wearing
course and over 40 % for the binder course. Basic field tests were done and advanced experimental assessments
were performed on asphalt mixtures for each subsection. This assessment included not only traditional test methods
as required by the standards, but also more advanced functional tests, including ageing simulation and workability
assessments.
The paper focuses on testing and characterization of asphalt mix workability and resistance to fatigue crack
propagation. Neither of the two characteristics is covered by any national or European standard and, therefore, the
established practice from North America is used. Workability is determined by compacting test specimens by
gyratory compactor to the selected level of target bulk density. Fatigue crack testing utilizes the same procedure
as in the case of thermal crack propagation. The only modification is the loading rate applied. The paper presents
extensive comparisons and asphalt mix performance assessments with respect to both of the aforementioned
characteristics.

Original document

The different versions of the original document can be found in:

• https://zenodo.org/record/1491657 under the license http://creativecommons.org/licenses/by-nc-nd/4.0/legalcode

• http://dx.doi.org/10.5281/zenodo.1491657,

https://zenodo.org/record/1491657 under the license http://creativecommons.org/licenses/by-nc-nd/4.0/legalcode

• https://zenodo.org/record/1491657,

http://dx.doi.org/10.5281/zenodo.1491656 under the license http://creativecommons.org/licenses/by-nc-nd/4.0/legalcode

DOIS: 10.5281/zenodo.1491656 10.5281/zenodo.1491657