City engineers in El Cajon, Calif., needed to resurface Washington Boulevard in a way that would improve the asphalt overlay’s performance while reducing lifecycle costs. Minimizing inconvenience to area residents was also a major concern. The existing overlay had significant reflective cracking that was caused by aging, oxidation and traffic. Reflective cracking is typically addressed by milling and replacing defective sections or overlaying large areas with a new, thicker overlay. However, these approaches only provide temporary solutions. Since cracks usually propagate back through to the surface fairly quickly, the overlay’s structural life is significantly reduced, prompting frequent maintenance intervals.
After consulting with representatives from Tensar International Corporation and Road Solutions Inc., the city decided to use GlasGrid 8501 as a full-coverage solution for the road. The product's .5-in grid aperture and 100-by-100-kN/m of strength provided a cost-effective means of dissipating crack energy over a large area and extending pavement life. It also allowed the city to accelerate work and limit the disruption of normal traffic patterns.
"The city’s staff had been using the GlasGrid System for about ten years," said Road Solutions Inc. President and Administrator Marshal L. Hughes. "Based on that experience, the city was confident that by incorporating the GlasGrid System’s self-adhesive reinforcement mesh into the rehabilitation, they could maximize the performance of the overlay, thus extending the maintenance interval significantly."
SRM Contracting & Paving began the installation process by milling and cleaning a designated section of road to a depth of approximately 3 in. Next, SRM’s crew installed an approximately 1-in-thick asphalt concrete leveling course to create a surface appropriate to receive the GlasGrid 8501 material.
A crew from Continental Western Transportation then applied PG 64-10 hot tack and used a specialized mechanical installer to apply the GlasGrid mesh to the leveling course. Finally, a top layer of tire-modified asphalt concrete was installed. This incremental process was repeated throughout the work zone until the project area was completely rehabilitated.
“The older streets where we have used the GlasGrid System are holding up really well,” said City of El Cajon Associate Engineer Michael Cardoza, who was in charge of the project’s design. “So once we decided to use the GlasGrid System, we didn’t expect to have to go back to that road for many years. In fact, my expectation is that these designs will last throughout my career.”