ASTM WK93649
New Test Method for Determining the Water-Soluble Chloride Ion Content in Granular Material used for Embankments, Subgrades and Retaining Wall Backfill
1. Scope
This test method is for the determination of water-soluble chloride ion content of as-received granular material that represents what will be used in the field for embankments, subgrades, and retaining wall backfill applications. The method involves measuring chloride ion contents using a chloride ion-selective electrode. 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. NOTE—This test method is partially based on the research conducted by National Cooperative Highway Research Program (NCHRP) Project 21-11 and Mineta Transportation Institute (MTI) Project 2225.Keywords
aggregate; coarse; coarse grained; coarse-grained material; granular; material; chlorideRationale
A chloride test method does not exist for coarse-grained material. ASTM D512 Standard Test Methods for Chloride Ion in Water and AASHTO T291 Determining Water-Soluble Chloride Ion Content in Soil, are not applicable for coarse-grained material as it requires the material to be crushed to pass a No. 10 sieve (T291) to remove larger particles. It is not appropriate to crush the coarse-grained material so that it would pass the designated sieve as in doing so, the chloride is altered and would misrepresent the material being used in the field. This document includes modifications offered by Tex-620-M in NCHRP 21-11, Determining pH, Chloride and Sulfate Contents in Soils and follows similar changes approved in D8262, Determining the pH of Granular Materials, and proposed work order WK71902, Measuring Electrical Resistivity of Granular Material, concerning sampling procedures. A similar work order WK93648 addresses sulfate ion content in granular materials.
Work Item Status
Date Initiated: 01-28-2025
Technical Contact: Fariborz Tehrani
Item: 000
Ballot:
Status: