IN SITU TEST FOR HYDRAULIC CONDUCTIVITY OF DRAINABLE BASES

The development and use of an in situ hydraulic conductivity test for drainable bases under existing pavements is presented. Six highway test sections were constructed by the Ohio Department of Transportation to test the drainage characteristics and durability of four unbound and two stabilized base materials. The in situ test was then used to determine the field hydraulic conductivity of the highway test section bases. This test uses an approach to Darcy's law called the direct velocity technique. A standpipe is placed in a cored hole in the pavement to establish steady-state horizontal flow through the base toward the edge drains. Two probes along a radial flow line measure differential pressure and electrical resistance in the water. An electrolytic solution injected at the standpipe is used to determine the water velocity as the median resistance is noted at each probe. The in situ hydraulic conductivity is calculated by dividing the discharge velocity by the hydraulic gradient. The in situ test provided results that compare favorably with published values from carefully controlled laboratory tests. It proved to work well for high-hydraulic-conductivity drainable bases, and it has the potential to be a valuable tool for condition assessment of bases under existing pavements.

Language

  • English

Media Info

  • Features: References; Tables;
  • Pagination: p. 36-40
  • Monograph Title: Effectiveness of subsurface drainage
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00725626
  • Record Type: Publication
  • ISBN: 309062160
  • Files: TRIS, TRB
  • Created Date: Sep 20 1996 12:00AM