Spectra - Roadway Improvement System
The Spectra Roadway Improvement System is a comprehensive approach for optimizing pavement performance using Tensar TriAx Geogrids. The system uses the multiple benefits of a mechanically stabilized layer (MSL), which consists of aggregate stabilized by TriAx Geogrid, to form a stiffer and more robust structure. But the Spectra System is more than just the MSL. It includes all the expertise, experience, design tools, support and service that Tensar International delivers – a complete solution for pavement design engineers and contractors.
The Spectra System has been used by state departments of transportation, county and municipal agencies, and private owners. It has been installed on projects ranging from low volume, light-duty rural roads and parking lots to high volume highways and heavy-duty industrial pavements. Projects incorporating the Spectra System have been approved and funded by the Federal Highway Administration (FHWA) and the American Recovery and Reinvestment Act (ARRA).
The Spectra System improves the economics and performance of roadway projects by:
- Reducing pavement component thicknesses including aggregate base course, asphalt and granular subbase
- Simplifying and speeding construction to avoid overexcavation and reduce undercut, disposal and backfill
- Decreasing labor and equipment requirements
- Improving durability, reducing maintenance requirements and extending service life
Lower Construction and Life Cycle Costs
The Spectra System paves the way to lower pavement construction costs by optimizing pavement components. Research indicates that use of the system can reduce asphalt layer thickness 15-30% and aggregate layer thickness 25-50%.
In addition, life cycle cost analysis indicates that the Spectra System – typically less than 5% of a pavement structure’s total in-place cost – can extend service life up to five times the duration of unstabilized pavements of equivalent thickness. Savings are achieved through preservation of the pavement structure, reduced maintenance, and extended rehabilitation intervals.