LWDs present a portable and safe alternative in material characterization and construction quality evaluation, and IRRF researchers are working to determine LWDs’ potential for future use in road construction. Currently, these layers are evaluated with a nuclear density gauge however, radiation exposure and the gauge’s inability to reflect the pavement’s mechanistic properties hinder its effectiveness. IRRF researchers are working with Alberta Transportation and C-TEP to investigate the effectiveness of light-weight deflectometers (LWD) in evaluating base and subgrade layers quality. Evaluation of Light-Weight Deflectometer (LWD) Performance The sections are also equipped with multi-depth deflectometers (MDD) to measure frost heaving, which is detrimental to pavement ride-ability in Alberta. The insulated sections and an adjacent control section are instrumented at various depths beyond the frost line to investigate the insulation’s effectiveness in limiting frost penetration and decreasing the negative effects of thawing. The IRRF has added both Styrofoam and bottom ash layers to its test road, where its performance will be observed over a number of years. Bottom ash is a byproduct of burning coal to generate electricity in Alberta, and as a result, is a locally and readily available material. As an alternative, the IRRF has partnered with the City of Edmonton and Alberta Transportation to investigate an alternate insulation option: waste bottom ash. Traditional road construction in cold regions has relied on Styrofoam to insulate the pavement’s subgrade layer from frost, which can be costly to roadway projects. Evaluation of Bottom Ash as Pavement Insulation Layer Alberta Transportation has provided the IRRF with seasonal FWD test results executed on a number of the Province’s highways so that researchers may analyze pavement behaviour throughout the year. To determine the effects of climate on our roads, the IRRF has partnered with Alberta Transportation to investigate how the flexible pavement responds to various traffic loads in different seasons. In regions like Alberta, pavement is subjected to deep freeze, followed by the thawing season. Seasonal Falling Weight Deflectometer (FWD) Testing This is a long-term project that will see researchers conducting a number of tests on the road’s behaviour over the next several years. The road itself consists of three test sections, each using a different type of TDA as embankment fill: off-the-road (OTR) tires, passenger and light truck tires (PLTT), and a PLTT-soil mixture. To determine the feasibility of using this recycled material in road construction, 825,000 waste tires, weighing approximately 8,000 tonnes, were processed into TDA and used to construct a test road. In collaboration with Alberta Recycling and Alberta Transportation, the IRRF is investigating the use of TDA as embankment fill. Evaluation of Tire-Derived Aggregate (TDA) as Embankment Material
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