Geosynthetics February/March 2024 - 44

FINAL INSPECTION
Tensar AX5-GN is used as an
anti-cracking measure for the
structural reinforcement, stress
dispersion and water resistance
of asphalt overlays. A layer of
bitumen emulsion is spread
over the bottom layer. Photo
courtesy of Vincent van der
Wielen, Joosten Groep.
Structural asphalt reinforcement
in Wassenaar, The Netherlands
M
PROJECT HIGHLIGHTS
STRUCTURAL ASPHALT
REINFORCEMENT
LOCATION
Wassenaar, The Netherlands
CLIENT
Municipality of Wassenaar
CONTRACTORS
D. Van Der Steen
Gebroeders Jansen
(asphalt reinforcement)
SUPPLIER
Joosten Groep in
collaboration with Tensar
GEOSYNTHETIC PRODUCT
Tensar AX5-GN
GEOSYNTHETIC
MANUFACTURER
Tensar
44
Geosynthetics | February March 2024
unicipalities are responsible for public space. Management plans describe which measures
must be taken for maintenance, repair, replacement, etc. The management plans are the
basis for activities and form the basis for the budget. In Wassenaar, an affluent suburb of The
Hague in The Netherlands, the asphalt of the Wittenburgerweg was due for maintenance. In
addition, an increase in the noise level was expected. The municipality of Wassenaar opted for
a complete reconstruction of the road and immediately provided it with quiet asphalt to reduce
noise. To increase the return on the investment, it was decided to use asphalt reinforcement.
After almost 25 years of use, with an extra-high traffic load due to bus traffic, strong cracking
was present in the existing road surface. The cracks had a random pattern, indicating fatigue of
the asphalt layer. Other cracks ran longitudinally, in the form of edge damage. To extend the life
of the new road surface, a crack-inhibiting measure had to be applied in the road construction.
Instead of tensile reinforcement (such as Tensar® Glasstex®), a structural reinforcement with a
stress-spreading function was chosen: Tensar AX5-GN.
Tensar AX5-GN is a geocomposite consisting of a rigid geogrid (TriAx) formed in one piece
with integrated nodes. The grid is connected to a nonwoven geotextile, or in other words, fleece.
Tensar AX5-GN is used as an anti-cracking measure for the structural reinforcement, stress
dispersion and water resistance of asphalt overlays. It is used in the construction of new and
the repair of existing asphalt roads.
A layer of bitumen emulsion is spread over the bottom layer. The AX5-GN reinforcement is
mechanically rolled out and pressed over it. This is done in two lanes, with a single overlap in
the longitudinal direction outside the tracks. After the emulsion has changed color from a glossy
brown to a dull black, also known as fluxing, asphalting is started. Because the fleece absorbs
the bitumen emulsion, a stress-spreading layer is created that prevents cracking. In addition,
the bitumen forms a water barrier that prevents water from penetrating into the foundation
through any seams in the asphalt overlay. G
Geosynthetics February/March 2024

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