ASTM D 8281/D8281M : 2021

1.1This test method covers the testing for and quantitative determination of the presence of swelling clays of the smectite group in rock for erosion control. The test particles are intended to be representative of erosion control rock and its durability. The test is appropriate for breakwater stone, armor stone, riprap and gabion sized rock materials.

1.2Ethylene glycol is one of the materials that react with swelling clays to form an organoclay complex having a larger basal spacing than that of the clay mineral itself. Rock containing swelling clay of the smectite group will be expected to undergo expansive breakdown upon soaking in ethylene glycol. If the amount, distribution, state of expansion, and ability to take up glycol is such as to cause such breakdown to occur, it may be expected that similar breakdown may occur of similar rock samples exposed, for longer times, to wetting and drying or freezing and thawing in a water-soaked condition in service.

1.3The prepared size of the rock specimens may eliminate some of the internal features present in the gross structure. The test specimens may not be representative of the quality of the larger rock samples used in construction. Careful examination of the rock source and proper sampling are essential in minimizing this limitation.

1.4The use of reclaimed concrete and materials other than natural rock is beyond the scope of this test method.

1.5Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. Reporting of test results in units other than SI shall not be regarded as nonconformance with this standard.

1.6All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026, unless superseded by this standard.

1.7This 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.

1.8This 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.