Abstract Manager

Saskatchewan recycles all tires, including passenger car and light truck tires, agricultural tires, and semi tires. It is environmentally and socially acceptable to recycle tires, and agencies in North America have been doing so for years. Recycling tires is important because scrap tires take up landfill space, pose a risk of fire when stockpiled incorrectly, hold water when not shredded, and can help conserve natural aggregate resources, depending on the application. Tire Derived Aggregate (TDA) is an engineered material made from shredded tires. TDA has been used in civil engineering applications as lightweight embankment fill to build road ramps, embankments, weigh scales, and to repair frost heaves for over 40 years.

In 2022, the Saskatchewan Ministry of Highways (ministry) constructed the ministry’s first highway embankment with TDA as lightweight fill in a highway embankment. A greenfield project site required a large fill and had in-situ soils that would benefit from the frost protection properties that TDA offers. The pavement design and construction were conducted according to ministry standards and the American Standard Test Method (ASTM) D6270-20 Standard Practice for Use of Scrap Tires in Civil Engineering Application. TDA was utilized as lightweight fill in an embankment section on Highway 6 south of Regina. The TDA embankment section was 58 m by 21.3 m and 2.85 m thick. A 3.7 m thick earth surcharge was placed on top of the TDA embankment to allow the TDA to settle. Two years following construction of the TDA embankment layer, the pavement structure was constructed on top of the embankment.

This paper discusses the embankment and surfacing design options explored, the TDA embankment layer design, and construction details including TDA shredding process, TDA storage, TDA quality assurance testing, challenges, and overall construction process. The TDA embankment layer environmental and geotechnical monitoring is also summarized.