BS ISO 18325:2015 pdf download – Geosynthetics — Test method for the determination of water discharge capacity for prefabricated vertical drains As the temperature correction (see Annex A) relates only to laminar flow, it is advisable to work at temperatures as close as possible to 20 °C to minimize inaccuracies associated with inappropriate correction factors, should the flow be non-laminar. NOTE The biological activity in the water is the one of facts for air bubbles, which will affect the index discharge capacity in a negative way. Some biocides have been shown to reduce the biological activity. Demineralized water of grade 2 according to ISO 3696 can also be used to prevent this risk of biological activity. 5.4 Pressure controller The pressure controller shall be provided for controlling the pressure of (10 ~ 300) kPa applied to the mounted specimen to an accuracy of ± 5 %. It shall be capable of maintaining the proposed pressure on the PVDs without any deformation which would influence the test results. 5.5 Equipment for determining the amount of water When the amount of water is determined by measurements of volume, a measuring vessel for determining the volume to an accuracy of 1 % is required. When the volume is determined by weighing, it shall be determined to an accuracy of 1 %. 5.6 Dissolved-oxygen meter, or apparatus in accordance with ISO 5813. 5.7 Stopwatch, for measuring time to an accuracy of 0,1 s. 5.8 Thermometer, to determine the water temperature used for the flow measurements to an accuracy of 0,2 °C. 6 Test specimens 6.1 Handling The sample shall not be folded and shall be handled as infrequently as possible to avoid disturbance to its structure. The sample shall be kept in a flat position without any load. 6.2 Selection Take specimens from the sample in accordance with ISO 9862. 6.3 Number and dimensions Cut three test specimens from the sample with the length parallel to the machine direction. The full width of the product shall be tested. 6.4 Specimen condition The specimens shall be clean, free from surface deposits and without visible damage or folding marks. 7 Test procedure 7.1 Cut the test specimens from the sample exposed to a temperature of (20 ± 2) °C for 24 h. The specimens shall be longer than the confined length. The geotextile portion that is unexposed to the pressure should be cut to ensure smooth...

Download Address

  • Download