Municipalities 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.
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
Geosynthetics product: Tensar AX5-GN
Geosynthetic manufacturer: Tensar