ASTM WK93648
New Test Method for Determining Water-Soluble Sulfate in Granular Material used for Embankments, Subgrades and Retaining Wall Backfill
1. Scope
This test method is for the determination of water-soluble sulfate 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 converting sulfate ion contents to a stabilized barium sulfate suspension under controlled condition and comparing measured turbidity of the solution to a curve prepared from standard sulfate solutions. 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; sulfateRationale
A sulfate test method does not exist for coarse-grained material . ASTM C1580 Standard Test Methods for Water-Soluble Sulfate in Soil, ASTM D8459 Standard Test Methods for Detecting Water Soluble Sulfates in Construction Soils, and AASHTO T290 Determining Water-Soluble Sulfate Ion Content in Soil, are not applicable for coarse-grained material as it requires the material to be crushed to pass a 600 sieve (C1580) or screened over the No. 10 sieve (T290) 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 sulfate 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 WK93649 addresses chloride ion content in granular materials.
Work Item Status
Date Initiated: 01-28-2025
Technical Contact: Fariborz Tehrani
Item: 000
Ballot:
Status: