Volume 34, N. 3, September-December 2011 | PDF(3 downloads)
This technical note presents some preliminary results obtained with the use of hydrophobic and hydrophilic tensiometers to measure liquid pressures in three-phase systems (air-NAPL-water). The porous tips of the hydrophobic tensiometers underwent a surface treatment known as silanization. The silanized tensiometers demonstrated little influence of the interstitial water in the measured values of NAPL suctions, the contrary occurring in the case of the standard ones. Due to water preferential wetability, the water tensiometers with standard porous stone tips presented adequate hydrophilic behavior, measuring water suctions satisfactorily. These tensiometers were also used to determine the soil-liquid retention curves (SLRC) of an eolian sand by vaporization. Water and diesel were used in the performed tests. The performance of the vaporization technique was satisfactory, reducing the time required for test accomplishment and presenting repeatable results. In the case of diesel, due its low vapor pressure and the selective nature of its vaporization process, the use of this technique was shown to be limited. Sample heating was used to accelerate the vaporization process.