Baran, E. 1994.
Use of Time Domain Reflectometry for Monitoring Moisture Changes in Crushed Rock Pavements.  
Proceedings of the Symposium on Time Domain Reflectometry in Environmental, Infrastructure, and Mining Applications, Evanston, Illinois, Sept 7-9, U.S. Bureau of Mines, Special Publication SP 19-94, NTIS PB95-105789, pp. 349-356
(posted June 10, 1996)

As part of an Accelerated Loading Facility trial conducted by the Australian Road Research Board and Queensland Transport, at the Department's full scale testing facility at Beerburrum, (Queensland - Australia) during 1992-93, ten test sites were instrumented with moisture probes designed to operate on the Time Domain Reflectometry principle. In all, eighty-two Queensland Transport designed probes were installed in the unbound crushed rock pavements and forty Commonwealth Scientific and Industrial Research Organisation designed probes installed in the subgrade. The moisture probes were monitored weekly to assess seasonal moisture movements and individual sites were monitored three times a week during artificial wetting and drying experiments. This paper presents findings of the studies together with findings from calibration of laboratory specimens and destructive sampling of field installations. One of the major findings of this study was the Topp's Universal Equation was unsuitable for high density crushed rock pavement materials and a modified calibration relationship had to be
determined. The study also found that the original three rod moisture probes would not work in a highly conductive sandstone pavement material and this was overcome with a redesign using an insulated center probe.