1350
Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
To successfully counteract reflective cracking, installed
reinforcement products must resist the installation influences
without damage and without significant loss of strength.
There is currently a lack of experience and knowledge
concerning the real residual properties “effective tensile
strength” of asphalt reinforcement products following their
installation and the subsequent paving installation procedure.
In the context of a diploma thesis at the RWTH Aachen
University, a test procedure to describe installation damage was
developed. One of the aims was to analyze and quantify the
“effective tensile strength” for two different asphalt
reinforcement products with different raw materials (polyester
and fiberglass) after the influence of installation damage.
Figure 1: Influences on asphalt reinforcement products during the
asphalt installation
2 INVESTIGATION AT THE RWTH AACHEN
UNIVERSITY
As part of the work to assess the resistance of asphalt
reinforcement products to installation influences, site-
appropriate tests were performed at the institute's installation
test track. As one goal, comparable tensile strengths of the
tested products after the following influences were intended to
be achieved:
• Only the influence of asphalt truck passes
• Only the influence of asphalt compaction passes
• Combination: The influence of asphalt truck and
compaction passes.
2.1. Test procedure
To determine the impact of truck traffic only, undamaged
specimens of the reinforcement products were placed on a clean
and even road and loaded by a truck. The applied load was
carried out by 35 passes with a speed of 20 ± 5 km/h without
any steering movements or braking activity (Figure 2).
Considering a truck with 5 axles who drives backwards to the
paver and forward again this corresponds to 3.5 delivery trucks
driving over the grid.
Figure 2: Influences due to truck traffic only
In preparation for the tests, an asphalt binder course (AC 16
B S) was installed on the base of the test track first. Onto the
binder course, each reinforcement grid has been placed
according to the manufacturer´s installation guidelines. Some of
the pre-damaged specimen (truck passes) have also been used in
the test-track for further exposure to simulate the double load-
effect, truck passes and compaction. To differ between
undamaged, pre-damaged and the different loading types, the
specimen had been placed into separate sections. Subsequent to
the installation of the reinforcement specimen a 50mm asphalt
wearing course was installed (Figure 3) and compacted with 6
roller passes (Figure 4).
Figure 3: Wearing course installation
Figure 4: Wearing course compaction
To test their tensile strength after the asphalt installation and
compaction, some of the specimen had to be removed after the
installation of the wearing course. For this reason these
specimen have been wrapped into an aluminium foil and coated
with a separating agent to create a very bad interlayer bond.
To investigate the different influences the test track was divided
into different sections:
A - An undamaged fiberglass reinforcement was installed,
followed by the installation and compaction of an asphalt
wearing course. (
Load influence: Compaction only)
B - An undamaged Polyester reinforcement was installed,
followed by the installation and compaction of an asphalt
wearing course. (
Like „A“, load influence: Compaction
only)
C - A pre-damaged fiberglass reinforcement was installed.
Subsequently the asphalt wearing course was installed and
compacted. (
Load influence: Truck passes and
compaction)
D - A pre-damaged Polyester reinforcement was placed.
Subsequently the asphalt wearing course was installed and
compacted. (
Like „C“, load influence: Truck passes and
compaction)