Paving The Way - Introducing GlasGrid
By: Rich Roberts
At L. Keeley, we strive to be the leaders and innovators of our industry. Our Paving Group offers a proactive, custom approach to the paving process and also provides innovative solutions to standard paving problems. By utilizing GlasGrid Technology, we are able to mend distressed pavement and prevent future cracking, saving valuable time and money in the process.
Tensile strength is the mechanical property of a material that describes its capability in resisting forces pulling in opposite directions. Inherently, asphalt has a very low tensile strength which is why cracking is one of the most common failures asphalt experiences. The asphalt is subjected to tensile forces in the direction of the arrow shown in the diagram. These forces cause a strain on the asphalt eventually forming a crack.
Asphalt pavement can fail due to a variety of reasons. One of the most common causes of failure is that the subgrade does not have enough strength to support the heavy and repeated loads it sustains. This means the stress and strain is much higher, and cracking occurs faster than asphalt that was laid on a firm, rigid subgrade. Traditionally, the solution to asphalt pavement failure is either complete sub-grade replacement or cement stabilization, which becomes a much longer and more expensive project.
The driving factor in the strength of the subgrade is the material that it consists of, how well it was compacted when installed, and the drainage that’s permitted throughout the lifespan. Exposing the layers under asphalt can all too often reveal that the subgrade is made of saturated clay, directly under the asphalt with little to no base rock to provide support between the two.
Fiberglass reinforcement has been an alternative to re-paving and replacement for a few years, but its effectiveness is now being proven in application. This Fiberglass reinforcement system adds a substantial amount of strength to pavement and can be used on projects where the subgrade is structurally deficient. It is a grid system that has a very high tensile strength in both directions, along with a substantial elastic modulus. A high elastic modulus means the Fiberglass grid can experience very large stresses with very small strains. In turn, this means that the Fiberglass grid works homogeneously with the asphalt to increase the tensile strength, decrease the strain on the asphalt, and significantly reduce the amount of cracking that will propagate to the surface.