The transmissivity flow rate tests were studies for 3 typical geosynthetic drainage products and calibration blocks at 4 different thicknesses and 20oC, 23oC, 27oC, and 30oC test temperatures. The test results indicated that the flow rates (qw) were greater than 0.3 liter/m-s and in the non-laminar flow condition. In general, the flow rates linearly increased as the test temperature increased. In addition, the flow rates non-linearly increased as the test hydraulic gradient increased for the test conditions. Since the tap water temperature for semi-tropical or tropical regions is generally higher than 23oC or 22oC, this study showed test flow rates were in non-laminar low conditions. A modified temperature and hydraulic gradient correction factor (RTi) for transmissivity test under non-laminar flow condition was formulized based upon the test results. The revised correction factors were much less than those specified by ASTM and ISO test methods.
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