Development of Geosynthetic Design and Construction Guidelines for Pavement Embankment Construction in North Georgia

Geosynthetics are becoming a popular alternative for soil improvement in highway construction to achieve enhanced performance in regions with soft problematic soils or to reduce aggregate base layer thickness to decrease construction costs. Subgrade soil improvement in a geosynthetic-reinforced pavement system is achieved by lateral distribution of vertical stresses at the reinforcing layer, through the tensile properties of the geosynthetic material, which is hard to measure with small-scale triaxial tests. Therefore, it is desirable to conduct large-scale testing to more accurately monitor the behavior of aggregate and soils under rolling wheel loadings when geosynthetic is present. The current study seeks to verify the behavior of geosynthetic-reinforced pavement systems through large-scale and bench-scale rolling wheel tests performed with problematic subgrade soils found in North Georgia. Large-scale and bench-scale specimens that mimic an aggregate base–geosynthetics–subgrade system were constructed at different subgrade soil conditions. Subgrades were constructed at a moisture content to produce a low California bearing ratio (CBR) or at optimum moisture content (OMC) during specimen preparation. Both an extruded biaxial geogrid and woven geotextile were placed at various locations in the aggregate base layer to investigate the optimal placement location for the different subgrade conditions. Pressure sensors were installed near the bottom of the aggregate base layer and near the top of the subgrade layer to monitor the vertical stress variations within the pavement system during trafficking. For large-scale testing, light weight deflectometer (LWD) and dynamic cone penetrometer (DCP) measurements were taken post-trafficking to determine the effects of the geosynthetics on the stiffness increase of pavement foundation layers. The results of this research indicate the effects of different subgrade conditions, geosynthetic reinforcement type, and geosynthetic placement location on the pressure experienced by pavement layers and the changes in stiffness of the aggregate base course.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 187p

Subject/Index Terms

Filing Info

  • Accession Number: 01704498
  • Record Type: Publication
  • Report/Paper Numbers: FHWA-GA-19-1611, Report No. 16-11
  • Contract Numbers: PI# 0015117
  • Files: NTL, TRIS, ATRI, USDOT, STATEDOT
  • Created Date: Apr 19 2019 12:19PM