Beginning in the 1930s, geotextiles and then geogrids have been used in unpaved and paved roads for the purposes of reduced stone base thicknesses and improved serviceability. For use as unpaved road reinforcement, the theory is developed to the point that the benefit/cost of using geotextiles or geogrids can be assessed. This application is very well positioned and accepted. For paved road stabilization, several geogrid design methods will be reviewed focusing on increased trafficability. Also, for paved roads under the assumption of lateral reinforcement, an observational approach to mitigate longitudinal cracks will be presented. Geotextiles have been used as separators to keep the crushed stone base course from mixing with the soil subgrade. Both geotextiles and geogrids will be described insofar as prevention of reflective cracks through asphalt overlays. Both theory and field behavior are presented.

Intended audiences

• Federal, state, and regional transportation, materials and geotechnical engineers
• Engineers from municipal districts and townships
• Private and municipal owners of all types of unpaved and paved roads
• General consulting engineers
• Soils and geosynthetic testing laboratories servicing these organizations
• Manufacturers and distributors of geotextiles and geogrids
• Contractors and installers servicing these applications
• Academic and research groups
• Others desiring technically related information on this important aspect of our infrastructure system

Primary discussion topics

This webinar, an essential aspect of geotextile and geogrid applications, focuses on the following segments:

• Introduction and background
  • Number of roads worldwide by country
  • Geosynthetics being considered
  • Soil subgrade strength categories
• Unpaved roads reinforcement with geotextiles and geogrids
  • Giroud and Noiray Model
  • Economics of reduced base courses
  • Prefabrication of geosynthetic panels
  • Overlapping edges
• Geosynthetics in paved roads
  • Subgrade to pavement
  • Functions
  • Design options
  • Why roads fail
  • Types of aggregate base
  • Cost justification
  • Lifecycle analysis
  • FHWA studies
  • Applications
  • Hydraulic enhancement
• Geosynthetic interlayers for pavements
  • Types
  • Installation
  • Functions
• Effects of moisture in pavements
• Types of moisture infiltration
• Moisture barriers
• Waterproofing design
• Retarding fatigue and cracking
• Pavement reinforcement using geosynthetics
  • Design
  • Testing
  • Milling and recycling
• Unbonded concrete interlayers
  • Function and applications
  • Cost analysis
• Solar reflective white geotextile
• Summary

Learning objectives

This webinar focuses on a comprehensive presentation of the use of geosynthetic applications with respect to unpaved and paved roads. Both geotextiles and geogrids are involved depending on exactly where in the roadway cross section they are placed. Of course, the quality of the soil subgrade is significant, and its role will be described accordingly.

More specifically, participants will learn about (i) design methodologies, (ii) the relevant test methods and procedures required for input data, (iii) numeric examples of the required stone or asphalt thicknesses, and (iv) what an owner or design consultant can realistically expect insofar as long-term field performance is concerned.

Webinar benefits

• Appreciate the very different applications of geotextiles and geogrids insofar as pavements are concerned
• Understand how the soil subgrade, stone base course, and pavement material function vis-a-vis the specific geosynthetic and its location in the cross section
• Appreciate where design models are fully developed, moderately developed or nonexistent
• Understand how laboratory test values of the geosynthetic material are used in the various design processes

Webinar instructor

George R. Koerner, Ph.D., P.E., and CQQ, is the director of the Geosynthetic Institute. He is in charge of laboratory accreditation, field certification and continuing education at the institute. He also manages several research projects and has published more than 350 technical papers in his 35-year association with polymers used in below-ground construction. Koerner’s Ph.D. is from Drexel University in geotechnical engineering. He is a registered professional engineer and a certified quality auditor. Koerner has received many awards over the years. The most notable being ATA’s Environmental Technologies Award of Excellence 1995, ASCE’s DVGI Geotechnical Engineer of the year in 2004, the title of ASTM Fellow in 2013 and GMA’s first Robert M. Koerner Lecture and Award in 2017.

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Webinars cost $200.00 for GSI and GMA members, and $250.00 for nonmembers. Successful completion of a multiple-choice test after the webinar carries 1.5 professional development hours (PDH).

For more information or to register, visit http://www.geosynthetic-institute.org/webinar.htm.