Repeatability and Reproducibility Study for Tube Suction Test

The Tube Suction Test (TST) was developed in a cooperative effort between the Finnish National Road Administration and the Texas Transportation Institute (TTI) for assessing the moisture susceptibility of granular base materials. This project was initiated by the Texas Department of Transportation (TxDOT) in order to develop a standard test procedure for the TST. The Materials & Pavements Division at the Texas Transportation Institute (TTI) and the Geotechnical Soils & Aggregates Branch of the Texas Department of Transportation (TxDOT) conducted a series of tests for determination of repeatability and reproducibility of the Tube Suction Test (TST) in a single lab and inter-laboratory between TTI and TxDOT. Four TxDOT districts (Yoakum, Tyler, Austin, and Waco) participated in the reproducibility study program. Brigham Young University also participated in this program as a subcontractor under TTI. Further research was conducted for determining different aspects with potential negative effects on the testing readings. The following factors were considered: the quality of the porous stones, the use of tap water versus distilled water in the sample molding procedure, and the surface texture of the sample.