What is it about?
Three filter paper test procedures (the initially wet contact, initially dry contact, and noncontact filter paper tests) were used for different testing durations to measure total and matric suction (water potentials) of geosynthetic clay liners (GCLs). These methods are discussed in terms of (i) their time and method dependencies, (ii) accuracy limits for total and matric suction measurements, (iii) applicability to a composite and complex material such as GCL and (iv) if the suction type that measured is the same as the suction type intended to be measured (i.e. matric or total suction).
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Why is it important?
Obtaining accurate water retention curves (WRCs) of geosynthetic clay liners (GCLs) is essential to assess their hydraulic barrier performance. The filter paper test (FPT) is accepted as a simple method to measure matric and total suction to obtain WRCs. However, special considerations are needed when the FPT is employed to measure a composite material with a high water potential range component such as bentonite. The applicable suction limits, testing time and the wetting-drying hysteresis impact of the different FPT procedures on different WRC paths (i.e. wetting or drying) of the specimens need to be considered.
Read the Original
This page is a summary of: Challenges of the Filter Paper Suction Measurements in Geosynthetic Clay Liners: Effects of Method, Time, Capillarity, and Hysteresis, Geotechnical Testing Journal, December 2021, ASTM International, DOI: 10.1520/gtj20200168.
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