Verification and Repeatability Analysis for the In Situ Air Permeameter Test

The air permeameter test (APT) is a relatively new test device that uses gas pressure and flow measurements to rapidly determine (<15 s/test) in situ hydraulic conductivity of granular materials. The use of precision orifices for flow rate control allows for high precision at low pressures (i.e., <25 mm of water pressure). Application of low pressure during testing is necessary to simulate typical field drainage conditions for pavements, and rapid testing allows for characterizing the in situ variability of hydraulic conductivity. This paper describes details of the APT device components and system, test operations, verification assessments, and measurement error calculations from repeatability testing. The results of this paper provide information for APT users to assess the test device and measurements and information needed to develop testing guidelines and test standards.