Time Domain Reflectometry (TDR) method was studied for the ability of monitoring the freeze-thawing cycle in soils. TDR is an established technology for measuring the volumetric water content. The dielectric constant and electrical conductivity (inverse of resistivity) of a soil specimen can be directly measured by analyzing a TDR signal. We found TDR measured soil dielectric constant during the freeze/thaw cycle clearly indicates the different stages of the freeze/thaw process, i.e., not only the onset of freeze or thaw process, but also the extent of their development. Based on this observation, a method is developed to directly estimate the degree of freeze/thaw from a TDR measurement. Compared with existing technologies for frost measurement, TDR has advantages in that it provides more details on the progresses of freeze/thaw status. Besides, it is rugged, inexpensive and automatic. These make TDR a promising tool to provide sound decision-support for pavement preservation in cold region.
Samenvatting