Friction after polishing – a new performance orientated test method in situ

Abstract

Friction of pavement surfaces and skid resistance are major functional requirements which have to be fulfilled
over the service time of pavements. The skid resistance in situ on a pavement surface is measured by non
destructive continuous measurement systems at traffic speed like SKM in Germany. To determine decisive
performance characteristics it is necessary to develop test methods which simulate the in-situ performance
realistically. So the question arises how to predict pavement performance concerning skid resistance for type
testing in laboratory. In Germany the test system of the Wehner/Schulze machine offers the possibility to
determine the friction of aggregates as well as the friction of real asphalt samples in laboratory. It is furthermore
possible to submit the specimen to accumulated polishing procedures to evaluate the changes in friction due to
simulated loading of the surface. The aim is to use this test method to evaluate friction performance in laboratory
to predict the performance of skid resistance over the service life of a pavement in situ.
In Europe today the resistance to polishing is only described by the resistance of aggregates against polishing by
determining the polish stone value (EN 1097-8). The influence of bitumen and the grading curve of aggregates
used for the asphalt mixture are herewith not taken into account. By using the Wehner Schulze machine and the
use of asphalt specimen in the friction after polishing test (FAP, EN 12697-49) a first step was made to tie
aggregates performance up to pavement performance in situ. With the new testing machine of BASt FAP test are
able to perform in situ on test sites. So in future is will be possible to survey pavements’ friction performance
over the service life of a pavement. This enables a realistic correlation of pavement performance in situ to
laboratory trials with simulated loading by polishing the specimen.
With the test method Friction after Polishing a test method is available to evaluate the performance of asphalt
with regard to friction already in laboratory to design an asphalt mixture with resists reliable the loading in situ
over its service life.

Original document

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

• https://zenodo.org/record/1456801 under the license http://creativecommons.org/licenses/by-nc-nd/4.0/legalcode

• http://dx.doi.org/10.5281/zenodo.1456801,

https://zenodo.org/record/1456801 under the license http://creativecommons.org/licenses/by-nc-nd/4.0/legalcode

• https://zenodo.org/record/1456801,

http://dx.doi.org/10.5281/zenodo.1456800 under the license http://creativecommons.org/licenses/by-nc-nd/4.0/legalcode

DOIS: 10.5281/zenodo.1456801 10.5281/zenodo.1456800