If you are an ASTM Compass Subscriber and this document is part of your subscription, you can access it for free at ASTM Compass
    ASTM D6766 - 20a

    Standard Test Method for Evaluation of Hydraulic Properties of Geosynthetic Clay Liners Permeated with Potentially Incompatible Aqueous Solutions

    Active Standard ASTM D6766 | Developed by Subcommittee: D35.04

    Book of Standards Volume: 04.13

      Format Pages Price  
    PDF 11 $60.00   ADD TO CART
    Hardcopy (shipping and handling) 11 $60.00   ADD TO CART
    Standard + Redline PDF Bundle 22 $72.00   ADD TO CART

    Significance and Use

    4.1 This test method applies to one-dimensional, laminar flow of aqueous solutions, such as chemical solutions, landfill leachate, and contaminated water (from here on referred to as “test liquid”), through saturated/hydrated GCL specimen that is consolidated and permeated under a prescribed or requested set of conditions.

    4.2 This test method assumes that Darcy’s law is valid and that the hydraulic conductivity is essentially unaffected by hydraulic gradient. The validity of Darcy’s law may be evaluated by measuring the hydraulic conductivity of the specimen at three different hydraulic gradients; if all measured values are similar (within about 25 %), then Darcy's law may be taken as valid. However, when the hydraulic gradient acting on a test specimen is changed, the state of stress will also change and, if the specimen is compressible, the volume of the specimen will change. Thus, some change in hydraulic conductivity may occur when the hydraulic gradient is altered, even in cases where Darcy's law is valid.

    4.3 This test method provides tools for determining flux and hydraulic conductivity values for a given GCL under the following two different scenarios, which should be specified by the requester:

    4.3.1 Scenario 1 – Hydrated/Saturated with Water Prior to Contact with Test Liquid—This scenario simulates the field conditions where the GCL is well hydrated with water prior to contact with actual test liquid. It should be noted that initial degree of saturation/hydration greatly affects the hydraulic properties of a GCL product. The test has two phases: (Phase 1) hydrate, saturate, consolidate, and permeate with water as Test Liquid 1, and (Phase 2) switch to permeation with test liquid as Test Liquid 2.

    4.3.2 Scenario 2 – Hydrated/Saturated with Test Liquid (Worst Case)—This scenario simulates the field conditions where the GCL is in contact with test liquid prior to being fully hydrated with water. It should be noted that this scenario may result in higher flux and hydraulic conductivity values compared to Scenario 1, as chemicals present in test liquid may alter the hydration and hydraulic properties of a GCL product.

    4.4 The apparatus used in this test method is commonly used to determine the hydraulic conductivity of soil specimens. However, flux values measured in this test are typically much lower than those commonly measured for most natural soils. It is essential that the leakage rate of the apparatus in this test be less than 10 % of the flux.

    1. Scope

    1.1 This test method covers laboratory measurement of both flux and hydraulic conductivity (also referred to as coefficient of permeability) of geosynthetic clay liner (GCL) specimens permeated with chemical solutions and leachates utilizing a flexible wall permeameter. For test measurement of index hydraulic properties of geosynthetic clay liners, refer to Test Method D5887/D5887M. For hydraulic conductivity compatibility of soils with aqueous chemical solutions and leachates, refer to Test Method D7100.

    1.2 This test method may be utilized with GCL specimens that have a hydraulic conductivity less than or equal to 1 × 10–5 m/s (1 × 10–3 cm/s).

    1.3 This test method is applicable to GCL products having geotextile backing(s). It is not applicable to GCL products with geomembrane backing(s), geofilm backing(s), or polymer coating backing(s).

    1.4 This test method allows the requester to evaluate the hydraulic properties of a GCL with site-specific or laboratory-prepared solution under different test conditions; thus, the test method also may be used to check performance or conformance, or both.

    1.5 The values stated in SI units are to be regarded as the standard, unless other units are specifically given. By tradition in U.S. practice, hydraulic conductivity is reported in centimeters per second, although the common SI units for hydraulic conductivity are meters per second.

    1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

    1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    D653 Terminology Relating to Soil, Rock, and Contained Fluids

    D854 Test Methods for Specific Gravity of Soil Solids by Water Pycnometer

    D2216 Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass

    D4439 Terminology for Geosynthetics

    D4753 Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and Construction Materials Testing

    D5887/D5887M Test Method for Measurement of Index Flux Through Saturated Geosynthetic Clay Liner Specimens Using a Flexible Wall Permeameter

    D7100 Test Method for Hydraulic Conductivity Compatibility Testing of Soils with Aqueous Solutions

    E145 Specification for Gravity-Convection and Forced-Ventilation Ovens

    ICS Code

    ICS Number Code 59.080.70 (Geotextiles)

    UNSPSC Code

    UNSPSC Code 30121900(Soil stabilizers and reinforcing materials)

    Referencing This Standard
    Link Here
    Link to Active (This link will always route to the current Active version of the standard.)

    DOI: 10.1520/D6766-20A

    Citation Format

    ASTM D6766-20a, Standard Test Method for Evaluation of Hydraulic Properties of Geosynthetic Clay Liners Permeated with Potentially Incompatible Aqueous Solutions, ASTM International, West Conshohocken, PA, 2020, www.astm.org

    Back to Top