Industry Sector & Application:
Civil Infrastructure
Location:
Calgary, Alberta
Featured Products:
Spartan Road Grid™
Featured Services:
Product Supply, Pre-Design Assistance, Consultation & Technical Support
Product Category:
Asphalt Reinforcement
Project Overview
Asphalt reinforcement is critical to preventing a variety of stresses that asphalt concrete pavements (ACP) are subject to during their life cycle. Without proper reinforcement, ACPs are subject to:
- Wheel path rutting
- Fatigue cracks
- Edge cracking
- Transverse and longitudinal cracks
In this application, the City of Calgary conducted three asphalt road rehabilitation projects using three variants of Titan Environmental’s Spartan Road Grid™ geogrids. Incorporating geogrids specifically designed for asphalt reinforcement in pavement construction or rehabilitation projects allowed the City of Calgary to achieve the following:
- Significant boost to the performance and service life of the paved infrastructure
- Reduction of asphalt overlay thickness
- Reduction of aggregate costs and on-going maintenance costs
Asphalt Reinforcement & Rehabilitation Requirements
One of the important challenges faced by any city is the effective maintenance of the roads in its jurisdiction.
The City of Calgary carries out maintenance and rehabilitation of the pavements periodically. In some cases, where the pavements have undergone extensive damage, reconstruction of the pavement also is carried out.
A condition assessment conducted by the city showed that:
- Nearly one-quarter of the city’s road network (3,300 lane kilometers or 2,050 lane miles) had met the trigger for rehabilitation.
- This backlog translated to more than 10 years of worth of budget.
- The allocated budget was only sufficient to treat about 275 lane kilometers or 170 lane miles.
Faced with construction and monitory constraints, the City of Calgary started exploring innovative and cost-effective methods for pavement rehabilitation.
The Conventional Solution
As with most urban pavement, milling and overlay/inlay is extensively used for the rehabilitation of distressed asphalt pavements, however, this does nothing to enhance pavement performance or longevity.
Titan’s Geogrid Solution
Titan proposed that the City of Calgary explore the benefits of using Spartan Road Grid™ asphalt reinforcement geogrids with the objective of enhancing pavement performance, longevity, and providing long-term cost efficiencies.
Developed through rigorous R&D and a series of technological advancements, these fiberglass geogrids are designed to improve the service life of roads. Their high tensile modulus reinforces the asphalt, thus enhancing resistance to fatigue cracking and rutting.
As a result, the asphalt pavement can be less thick, yet have the same structural strength as unreinforced asphalt pavement of greater thickness.
The City of Calgary decided to carry out pilot studies in three locations to monitor the performance of Titan’s Spartan Road Grid™.
Putting Spartan Road Grid™ to the Test
Sarcee Trail Project
Conventional Solution: Mill 100 mm & inlay 100 mm (ACP)
Spartan Road Grid™ Solution: Mill 70 mm, inlay 30mm ACP, install Spartan Road Grid™, inlay 40 mm ACP)
Pre-Rehabilitation Condition:
- Extensive medium and high severity transverse and longitudinal cracks on both lanes. Closely spaced at 5m (16 ft) intervals.
- Semi-continuous wheel path fatigue cracking of low to medium severity in the median lane.
- Negligible rutting.
- Negative slope (sloped towards the median) on the median lane was observed in certain areas.
- Extensive potholes where longitudinal and transverse cracks intercept.
101 Street Project
Conventional Solution: Mill 80 mm and inlay with ACP 80 mm thick in two lifts (30 mm + 50 mm)
Spartan Road Grid™ Solution: Mill 40-50 mm, lay Spartan Road Grid™ fiber-glass composite geogrid, and place ACP 40-50 mm thick
Pre-Rehabilitation Condition:
- Moderate and high severity centerline and longitudinal cracks in both lanes. Transverse cracks were spaced at 20 m (65 ft) intervals on average and about 20-25mm (0.7-0.9 inches) wide. Most of them were sealed.
- Intermittent low severity rutting: average rutting was less than 9mm (10.4 inches).
- Semi-continuous wheel path fatigue cracking of medium to extreme severity; extensive potholes.
- Several asphalt patches were placed over localized failures in the wheel paths. The moisture trapped in the subgrade meant new patches were not lasting more than a few weeks, requiring significant maintenance in the spring and summer seasons.
50th Ave Project
Conventional Solution: Mill 110 mm inlay 110 ACP
Spartan Road Grid™ Solution: Mill 90 mm, Inlay 40 mm ACP, install Spartan Road Grid™ fiberglass geogrid, 40-50 mm thick
Pre-Rehabilitation Condition:
- Severe rutting at intersections.
- Moderate rutting throughout the length.
- Slight fatigue cracking.
Key Takeaways
- Achieving a strong interface bond with proper installation are key to reliable performance.
- Spartan Road Grid™ 10C (fiberglass grid composite with thick nonwoven geotextile) should only be installed directly over fine milled surfaces. For rough milled surfaces, a thin ACP overlay underneath the fiberglass grid composite is recommended for achieving a stronger bond.
Benefits of Spartan Road Grid™ For Asphalt Reinforcement
- Extends pavement life.
- Provides cost benefits by increasing pavement life cycle.
- Fast, easy installation, and recyclable.
- Reduces overlay thickness to a minimum of 50 mm.
Technical Breakdown of Spartan Road Grid™
Spartan Road Grid™ 10C (First Generation Composite)
(Fibreglass composite grid with very thin non-woven geotextile)
- Bituminous coated composite geogrid made of biaxial fiberglass geogrid bonded to a thin 50gsm spunbonded non-woven polyester geotextile.
- Provides a moisture-proofing benefit that ensures faster installation over milled surfaces.
- Bituminous coating ensures proper adhesion to the asphalt layers over the tack-coated surface and optimizes the chemical compatibility between the geogrid and the pavement overlay.
- Product Specifications
Spartan Road Grid™ 10C (Second Generation Composite)
(Fiberglass composite grid with thicker nonwoven geotextile)
- Biaxial geogrid bonded to a needle-punched nonwoven geotextile.
- Specifically designed for asphalt reinforcement with an additional moisture proofing benefit.
- Composite characteristic provides a continuous non-deforming water-resistant barrier.
- Polymer coated which ensures proper adhesion to the asphalt layers over the tack coat surface, and further optimizes the chemical compatibility between the geogrid and the pavement overlay.
- Product Specifications
Spartan Road Grid™ 10
(Fibreglass grid alone)
- Specifically designed for asphalt reinforcement.
- Optimal apertures allow asphalt particles to penetrate through the grid to achieve high interlock and effective bonding of the two asphalt lifts.
- Polymer coated which ensures proper adhesion to the asphalt layers over the tack coat surface, and further optimizes the chemical compatibility between the fiberglass reinforcement and the pavement overlay.
- Product Specifications
Spartan Road Grid 10C (First Generation)
Titan Environmental geogrids are exceptionally durable, biologically unaffected by soil micro-organisms, inert to all chemicals normally found in the soil, and formulated to resist ultraviolet degradation.
All Titan Environmental product solutions are backed by comprehensive engineering and specialized technical support. We are happy to provide complimentary application-specific preliminary designs. We can also provide detailed design and working calculations including construction drawings, and crucial specifications and installation details.
Explore what Spartan Road Grid™ can do for you.
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