Polyester geogrids as asphalt reinforcement-a sustainable solution for pavement rehabilitation
Abstract
The conventional method for rehabilitation of cracked concrete or asphalt pavements is the installation
of new asphalt layers. But a new overlay does not make the cracks disappear; they are still present
in the old asphalt layers. Because bituminous bound materials are unable to withstand the high tensile stresses
that result from external forces like traffic and temperature variations, these cracks rapidly propagate into the
new asphalt overlay. This phenomenon, known as reflective cracking, is one of the major problems associated
with the use of asphaltic overlays. In order to tackle the problem of reflective cracking and to therefore prolong
the service life of a pavement, a reinforcement grid made of high modulus polyester has proven to be a
very effective solution. Geosynthetics as asphalt reinforcement have consistently shown outstanding results in
addressing the issue of crack initiation and propagation, eliminating the damage caused by water intrusion
that ultimately leads to the failure of the pavement structure. The increased pavement life achieved by the use
of this technology not only prevents excessive disruption to traffic flow and local business, but it also demonstrates
strong environmental and economic benefits. Through basic theory and practical experiences this paper
will demonstrate the success and extended pavement life that can be achieved in both highway and airfield
applications. Special attention is given to a comparison of Embodied Carbon Dioxide for different
rehabilitation methods showing the sustainability of using polyester asphalt reinforcement to extend pavement
life.
Conclusion
Reflective cracking occurs in rehabilitated asphalt
pavements. High tenacity Polyester as raw material
is often chosen because of the high compatibility of
its mechanical behaviour to the modulus of asphalt
and its good behavior under dynamic loads. A bituminous
coated Polyester asphalt reinforcement grid
can show excellent results in delaying reflective
cracking. This has been shown by numerous practical
examples from the past several years.
Using this information combined with the amount
of embodied carbon dioxide (ECO2) of construction
materials used for a typical pavement rehabilitation
project, a comparison has been made between a reinforced
and an unreinforced solution. The comparison
shows the significant savings of 63 % ECO2 per year
of design life of the reinforced as compared to the
unreinforced overlay. This substantial saving is
achieved by extending the pavement life and thus
reducing the need for maintenance and the corresponding
ECO2.
Similarly to the saving of embodied carbon dioxide
a significant cost saving per year of design life is
achieved. This again shows that saving the environment
and saving costs go very well hand in hand.
This paper has shown that asphalt reinforcement
made of high modulus polyester does provide an efficient
solution to save resources by extending
pavement life and thus creating sustainable pavements.