Combigrid® 30/30 Q1 151 GRK3 Geogrids from NAUE provided base course reinforcement for the rebuilding of an 1,100 metre stretch of Canada’s Highway 21 through the town of Kerrobert.

Highway 21 is a major North-South road in the Canadian province of Saskatchewan, which runs for 450 miles from the north of the province to the United States border. At the town of Kerrobert the road has junctions with Highways 31 and 51; providing strategic links to the regions oil and gas industry. With constantly high traffic levels of heavy semi-trucks on the section through Kerrobert, the road has always been notorious for its inherently poor performance, with soft shoulders and weak structure.

For the latest road rebuilding project on Highway 21, Saskatchewan Ministry of Highways & Infrastructure specified that a composite, non-woven, geotextile/bi-axial geogrid be installed between the subgrade and sub-base course layers to meet precise structural design requirements.

Contractor, HJR Asphalt Partnership selected NAUE Combigrid® 30/30 Q1 for the project. Combigrid® is a rigid multi-directional geogrid for reinforcing pavements; it provides a stable platform on soft ground, and also reduces the depths of aggregate required.

Geogrids used in the reinforcement of pavements and subgrades are subjected to high impact loads of short duration. Combigrid® excels in this application due to the inherent strength in the Geogrid bars. Combigrid® is the next generation of Geogrid, produced with state-of-the-art manufacturing technology unlike any other Geogrid on the market today. The reinforcement element is a highly orientated polypropylene bar that is uniformly extruded and drawn to achieve a high modulus and strength at low elongation, and excellent radial stiffness. This is combined with NAUE patented welding technology to provide a structurally sound and stable Geogrid with 100% junction efficiency at working strains.

Rob Meyers, Project Manager at HJR Asphalt Partnership, explains: “We used a total of 50 rolls of Combigrid® (4.75m x 100m) for the 1,100m stretch of the highway. To enable us to meet the limited site occupancy timescales it was important that we had a product that was easy to maneuver and install. Once the existing road material was excavated, we were able to simply roll out the Combigrid to cover the sub-base – all within the same day. Combigrid worked extremely well and we achieved our specified densities on the base course and asphalt with relative ease. It meant that we completed this section of the project in 15% less time than we estimated in our bid. We were very impressed with the NAUE product and, when the town asked us to replace another road in Kerrobert, we included Combigrid in our quote to ensure we had extra strength underneath our surfacing structure.”

Project Name: Highway 21 Road Rebuilding, Grading and Paving
Date: May/June 2015
Client: Saskatchewan Ministry of Highways & Infrastructure
Contractor / Installer: HJR Asphalt Partnership
Product: Combigrid® 30/30 Q1 151 GRK3