ASTM D8262-22

5.1?Granular material being used in embankments, subgrades, and retaining wall backfill must often meet certain specifications relating to corrosion potential, such as pH and electrical resistivity. This standard is used by manufacturers, suppliers, and recipients of the materials to measure the pH of the material for acceptance for its intended use.

5.2?Retaining wall manufactures often use a granular material specification similar to: 100 % passing the 100 mm (4 in.) sieve, 75-100 % passing the 75 mm (3 in.) sieve, and 0-15 % passing the 75 ?m (No. 200) sieve. The specification may vary depending on availability of local materials.

5.3?Since the total surface area of the material being tested affects the test results, the sample and specimen must have the same grading as the material specified or proposed for use. Reducing the particle size by crushing is not permitted since this process may alter the pH of the material and will likely not be representative of the material actually being placed in the field.

1.1?This 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.

1.2?The 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.

1.3?The 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 ?m (No. 200) sieve.

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

1.5?UnitsThe 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 ?m, 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.

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values shall conform to the guidelines for significant digits and rounding established in Practice D6026, unless superseded by this test method.

1.7?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.

1.8?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.