ASTM D 8262 : 2022

1.1This test method uses a pH meter to measure the pH of as-received granular material that represents what will be used in the field for embankments, subgrades, and retaining wall backfill applications. The principal use of the test method is to supplement soil resistivity measurements to identify conditions under which the corrosion of metal embedded in granular material, or in contact with the granular material may be sharply accentuated.

1.2The pH of granular material is often specified by agencies to meet criteria that are necessary to prevent or reduce corrosion of metal objects embedded in the granular material used in embankments, subgrade, and retaining wall backfill.

1.3The types of granular material that can be tested for pH using this standard are natural or manufactured coarse sand, natural or crushed stone, natural or crushed gravel, air-cooled blast furnace slag, and aggregates: lightweight, heavyweight, or normal weight. According to AASHTO M 145, these granular materials generally fall into AASHTO classification groups A-1, A-2-4, A-2-5, or A-3. The ideal material is a well-graded, free draining material that has less than 10-15 % passing the 75 μm (No. 200) sieve.

1.4This test is based on the volumetric method because the unit weight of the fill material will vary depending on source and project specifications.

1.5Units—The values stated in SI units are to be regarded as standard. Except the sieve designations, they are identified using the “alternative” system in accordance with Specification E11, such as 3 in. and No. 200, instead of the “standard” of 75 mm and 75 µm, respectively. No other units of measurement are included in this 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values shall conform to the guidelines for significant digits and rounding established in Practice D6026, unless superseded by this test method.

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.