Using Geosynthetics in Roadway Design
- Dec 08, 2018 -

Over the past 30 years, civil engineering projects have utilized geosynthetics to optimize the design and/or increase the longevity of particular systems. This includes roadway design by enhancing subgrade stabilization and more recently optimizing the trafficked structure, be it a paved or unpaved roadway.

It is common knowledge that road structures fail prematurely due to many unfavourable factors including subgrade conditions, environmental factors, traffic patterns, water infiltration and inadequate drainage, lateral displacement and weakening of base course aggregate. The unfavorable effects of these aspects can become extremely time consuming and costly to fix irrespective of regular maintenance; therefore, significant strategies are required for long-term maintenance or rehabilitation. However, such remedies are often temporary or unsuccessful because they only treat the symptom, rather than the cause of the problem.

To safeguard against these unfavourable factors, technological systems have been developed with the use of geosynthetics. However, they should be specified during the initial design stage for them to provide optimum performance during and post construction. Within roadway design, geosynthetics are commonly used for separation, filtration, drainage, stabilization, reinforcement and crack mitigation. Invariably their use in these applications improve the performance of roadway structures by extending their longevity.

In addition to improving structural performance, geosynthetics offer many other advantages including:

  • Economic: the structural strength provided by geosynthetics allows for the installation of thinner aggregate base course sections, reduced asphalt thickness, and improved performance, thus costing less up front as well as over the long-term lifespan of the road. There is also cost-savings realized in the installation labour and transportation of aggregate.

  • Social, political and environmental benefits: by reducing the reliance on natural and non-renewable resources, we reduce the damaging effects of harmful greenhouse gas emissions associated with the mining, processing and transportation of aggregate materials. Geosynthetics offer innovative solutions to the construction industry for building greener roads, akin to LEED certification, thus lowering the environmental impact.

  • Safety: using geosynthetics minimizes the aggregate mining and transportation requirements, decreasing the number of truck loads travelling long distances across our provinces to site. Installation is also simpler and requires less equipment than conventional construction methods to build the trafficked structure.

  • Time: expedited construction timelines occur with geosynthetics usage because they require less excavation and compaction for subgrade stabilization, are lightweight and easy to install, are usually in stock and ship quickly, and can be installed during short construction seasons or during short bouts of good weather conditions.

  • Engineered quality and performance advantage: geosynthetics are engineered in controlled environments and extensively tested to ensure performance and product quality. Adversely, soil and aggregate generally vary significantly across a construction site or region and are subject to deviations in weather, handling and compaction.

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