Handy Geotechnical Instruments, Inc

The Pavement Permeameter

NEW! After testing four prototypes we are ready. The Pavement Permeameter measures in-place permeability of exposed base and surface course pavement layers.

  • Get an instant measure of permeability from the rate of gas flow measured under controlled conditions.

Degradation of compacted stone is expensive and time-consuming to evaluate by sampling and sieving, and can become critical factor affecting drainage, pavement pumping

Some facts about The Pavement Permameter:

  • Uses compressed air, CO2, or nitrogen.
  • Gas pressure is adjustable and regulated, with digital readouts for pressure and flow rate.
  • Stable readings in less than a minute.
  • Tilt-up handle for lifting, and two-wheeled cart for rapid readings and contouring of an area.
  • Laminar flow confirmed, enabling application of the Darcy Law modified for compressibility.
Pavement Chart 1

Tests at grid intersections correlate with excess fines (>11% passing No. 200 sieve) in the red areas. Modified from White et al. (2007).

Pavement Chart 2

Does layer thickness matter in a surface test? (The theoretical development assumes an impermeable underlayer.) Not much if the layer thickness is more than about 10 cm (4 inches), and hardly any when 20 cm or more. Geometric factors were developed using finite difference solutions.

The Pavement Permeameter is a quality control instrument that enables quick corrections by immediately informing the engineer and/or contractor if and when there is a problem.

This instrument was developed by students and faculty at the Spangler Geotechnical Laboratory of Iowa State University, and Geosystems Engineering, Inc., Lenexa, Kansas, sponsored by the Iowa DOT and US DOT-FHWA. Design is by Eichner Engineering, Ames, Iowa.

Pavement Image 2

Pressure is manually adjustable, with electronic readouts of pressure and flow rate. Optional connection to a laptop for rapid data reduction. May be operated with compressed air; CO2 gas cylinders optional. The special cart is a recommended accessory.

Pavement Image 3 Pavement Chart 3

Calculated pressure contours. Modified from White et al. (2007).

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