Geosynthetic reinforcement and stabilization – impact on pavement performance

The roads of the national highway system are a critical asset, and their performance directly impacts the economy, commerce and social connectivity of the country. 

Therefore, designing and constructing durable roads that can withstand the anticipated loading conditions in consideration of the variable and changing conditions of the subgrade is key. Utilizing geosynthetics to enhance and optimize the stability of pavement foundations is an important strategy which can be implemented to extend the design life and deliver a more durable and efficient pavement system. 

Geosynthetics provide mechanical stabilization of the unbound materials utilized as the pavement foundation. Geosynthetics increases the tensile resistance and confinement of these soil layers, which results in a stronger and stiffer pavement section. This helps distribute the traffic load from the surface to the natural subgrade by distributing the load more efficiently. This results in lower, more uniform stresses at the subgrade which can significantly reduce the likelihood of ruts as well as minimizing their depth. Common types of materials that are used for this application are geogrids, geotextiles and geocells. In some cases, a combination of products can be used.  

Research over the years has demonstrated the ability of geosynthetics to improve pavement performance as described. The results of the improved section can be used to optimize the design by either allowing a higher loading conditions (magnitude and/or number of passes), a reduction in section thickness to support the same load, or by increasing the design life. In many cases, a combination of these benefits can be the most efficient.  

The use of geosynthetics increases design flexibility, allowing the designer to choose how to optimize the design for the specific site conditions and project requirements. For example, reducing section thickness can be the most important requirement due to other design considerations such as limiting excavation depths because of utilities. Another example is to increase the time between maintenance cycles to minimize the impact of congested roads. It is recommended to consider a life-cycle cost analysis when evaluating alternatives.    

In addition, there are potential sustainability and environmental benefits that can be considered. Reducing the overall pavement thickness results in reduced excavation as well as demand for importing select base and subbase materials reducing the impact of transportation. If one extends the service life, then this can result in reduced impact due to increased time between maintenance cycles as well as the impact due to reduced congestion during construction periods. 

The future of pavement design and construction will need to consider the long-term performance and increased service life desired by transportation agencies. The use of geosynthetics to improve performance, longevity and life-cycle cost while potentially improving the sustainability and resiliency of the project should be an important consideration.  

For additional information:

• 2025 Transportation Statistics Annual Report
  • https://www.bts.gov/sites/bts.dot.gov/files/2025-12/BTS_TSAR-2025_Annual-Report_123125.pdf
• National Highway Institute (NHI) Courses:
  • Geotechnical Aspects of Pavements No. 132040
    • Course Reference, FHWA NHI-05-037
  • Geosynthetic Course No. 132013
    • Geosynthetic Design & Construction Guidelines, FHWA-NHI-07-092

Daniel Alzamora, P.E., is a contributing editor for Geosynthetics and has spent more than three decades in the geosynthetics industry in both the public and private sector.