Mainroad Lower Mainland Contracting is responsible for the maintenance of Highway 99. This Ministry of Transportation & Infrastructure Provincial Highway is one of the major highways heading south from the Lower Mainland / Vancouver area towards the U.S. Border. With a traffic count of over 50,000 vehicles per day, Highway 99 is considered a Class A category road for maintenance work
As a late season addition to the maintenance contract, a section of Highway 99’s south bound, slow lane south of the George Massey Tunnel required surface repairs to maintain a safe and trafficable condition heading into winter. Significant sections of the slow lane were showing signs of considerable surface cracking and general deterioration. The usual repair method in these circumstances is a “grind and pave” repair where the pavement is ground / milled out to a depth of 50mm and re-paved. Due to the late season, the use of regular asphalt for this repair was avoided as the temperatures and weather conditions are notoriously cold and wet at this time of year in Vancouver. EZ Street Asphalt was recommended for this work as the material is not affected by the cold or wet weather and can still be installed in the same manner as regular asphalt.
The project took place on the overnight shift on Friday, December 7th, 2012. The weather was dry overnight even though it had rained significantly during the day. The temperature was stable at about 1C through most of the shift.
The south bound lane of Highway 99 has an average daily traffic count of around 30,000 vehicles. The repairs were all in the slow lane with the full lane width being removed to a depth of 50mm. Three large patches were repaired with two of these being around 100m in length each while the third was approximately 1km long. The third and longest repair also ran underneath the three newly constructed overpasses for the new South Fraser Perimeter Road which is currently under construction.
During the grinding operation, some investigation work was performed on the areas to be resurfaced. It was found that on all three patches, the surface cracks continued down through the top 50mm layer being repaired into the base of the asphalt pavement. While the grind and pave was creating a new surface it was not eliminating or removing the damage to the pavement. In addition, a significant amount of water and dampness was found under the 50mm surface removal and in the base level test hole. The flexibility and crack resistant properties of EZ Street Asphalt is ideal for this situation. EZ Street will help to minimise the reflective cracking over the damaged base and the self healing properties will preserve the surface integrity should any cracks make their way through the new surface. Also, as EZ Street is not effected by the water, the moisture under the surface should have no impact on the new surface.
Approximately 5,700m2 of new pavement was installed overnight in the “grind and pave” operation with 625mt of EZ Street Asphalt being utilized. As EZ Street Asphalt is lighter than regular asphalt with a weight of around 2.2mt/m3 instead of the normal 2.4mt/m3, the project used around 55mt less material than it would if it had been regular asphalt. As with previous EZ Street paving projects, the installation / paving was performed almost identically as with regular asphalt. The same equipment and crew installed the cold EZ Street the same as they would have installed the hot asphalt.
The EZ Street Asphalt product was produced a few days in advance of this project and was made with a kinimatic viscosity alot higher than with a normal maintenance mix. With the 625mt being installed on a high traffic volume highway, we wanted to provide a material that would set up faster than our usual maintenance material which is designed to have a much longer shelflife.
Overall the project went well. EZ Street Asphalt was installed by an experienced paving crew and the end result is a smooth and very quiet surface. In addition, the new EZ Street surface has been observed to be significantly dryer than the surrounding existing asphalt surface during wet weather. The open graded surface as well as EZ Street’s water shedding properties have very obvious and visual benefits for the new surface.