He reinforcement of asphalt layers with geogrids has established itself as an effective solution to improve the structural performance and extend the service life of pavements. These structures, placed between layers of asphalt mix, control crack propagation, reduce permanent deformation and increase resistance to cyclic loading.

In this article we analyze how the most common materials - polyester and fiberglass - influence the behavior of geogrids and why they are used. Fortgrid Asphalt offers significant advantages in road projects.

Influence of raw material on geogrids for asphalt layers.

The choice of material is crucial to ensure the strength and durability of a geogrid.

Polyester:

  • Polymer with high elasticity and thermal stability.

  • High resistance to cyclic loads.

  • It retains its shape and recovers its elasticity after repetitive stresses.

Fiberglass:

  • Silica filaments with high tensile strength but low elongation.

  • Vulnerable to compression and bending.

  • Limited capacity to resist cyclic loads and permanent deformations.

 

Figura 1. Ensayo a carga cíclica bajo norma AASTHO T 321


Figure 1. Cyclic load test under AASTHO T 321 standard.

Comparative Tests: Fortgrid Asphalt vs. fiberglass

Under the standard AASTHO T 321The performance of both geogrids was evaluated in reinforced and unreinforced specimens. The failure criterion was the complete propagation of a pre-existing crack.

Increased number of charge cycles

Fortgrid Asphalt  significantly increases the load cycles necessary for failure, thanks to its manufacture in high tenacity polyester and its bituminous coating.

Interface shear strength

The balance between strength, open area and formulation of the impregnation copolymer improves adhesion to the asphalt mix.

Improved behavior under dynamic loads

Polyester offers a wider and more stable elasticity range than fiberglass, which is stiffer and more brittle.

4. Less damage during installation

Fortgrid Asphalt retains more than 93 % of its original strength after installation, compared to 39 % for fiberglass.

Conclusion

The selection of geogrids for reinforcement of asphalt layers should be based on broader criteria than tensile strength. Fortgrid Asphalt stands out for its excellent performance under cyclic loading, high shear strength and durability from installation, making it a superior solution to fiberglass options.