Authored By: Tensar International
Pavement engineers are often charged with delivering a high-performing design on a dismal construction budget. With client expectations increasing and roadway construction and maintenance budgets steadily on the decline, “miracle worker” has become a major part of the job description. It’s obvious that conventional design methods are no longer cutting it. However, forward-thinking engineers are gaining traction with alternative strategies like pavement optimization to design the best performing roads for the lowest cost.
So, what is pavement optimization? It’s an innovative concept in pavement design that gives the designer three choices:
1) Optimize for initial cost
Significantly reduce the pavement thickness --> Get the original design life but save on initial costs
2) Optimize for (cost neutral) pavement performance
Slightly reduce the pavement thickness --> Get 3x the original design life and pay the same initial cost
3) Optimize for life cycle cost
Use the same pavement thickness --> Pay more up front on the construction but greatly reduce life cycle cost.
The next question you may have is, “How can I possibly get improved performance by decreasing pavement thickness?” Reducing pavement thickness may seem counter-intuitive, however, a product known as TriAx Geogrid is the key that makes pavement optimization a viable strategy.
A geogrid is a geosynthetic material used to stabilize soil. Geogrids have openings, called apertures, which allow aggregate to strike through and provide confinement and interlock. Aggregate movement is greatly minimized and stiffness values are improved and maintained over time. Research has shown that integrating this stiffened layer, known as a mechanically stabilized layer (MSL), into the design improves the long-term performance of the roadway. Pavement optimization works within AASHTO design methodology, allowing engineers to precisely quantify the benefit of integrating an MSL into the roadway section.
TriAx is the most advanced type of geogrid due to its triangular apertures and high profile ribs. The triangular shape allows traffic loads to be spread over a wider area, lessening the impact to the sensitive subgrade soils. The high profile ribs improve interaction with aggregate, improving stiffness of the MSL. Tensar, the manufacturer of TriAx, has conducted over 1,000,000 ESALs of research to study the effect of geogrid on pavement design. This research has been validated by leading experts in the field. Now, engineers can design for increased performance and lower design risk, while maximizing the project’s cost-effectiveness.
Real World Example: One roadway project in Orchard Park, NY saved over $1 million by using TriAx Geogrid in the design. Click here for the project details.
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Pavement Optimization Basics Webinar: Want to learn more about pavement optimization and how you can start applying it to your roadway designs? Join us for our online course.
Start designing better pavements for your project and discover the true value of using TriAx geogrids in your pavement sections. Download Tensar's trusted SpectraPave Design Software today and tap into the full benefits of Tensar's knowledge and experience in analyzing both subgrade stabilization and pavement optimization applications.
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