AASHTO M143-14-2022 Rock Salt Specifications.pdf

Standard Specification for

Sodium Chloride

AASHTO Designation: M 143-14 (2022) Technically Revised: 2014 Reviewed but Not Updated: 2022 Editorially Revised: 2022

Technical Subcommittee: 4c, Markings and Coatings

American Association of State Highway and Transportation Officials 555 12th Street NW, Suite 1000 Washington, D.C. 20004

Accessed by account: Illinois Dept Of Transportation | User: Kristy Brod | Date: Tue May 20 16:07:37 UTC 2025 | IP address: 206.176.14.223

TS-4c M 143-1 AASHTO

Standard Specification for

Sodium Chloride

AASHTO Designation: M 143-14 (2022) Technically Revised: 2014 Reviewed but Not Updated: 2022 Editorially Revised: 2022

Technical Subcommittee: 4c, Markings and Coatings

1. SCOPE

1.1. This specification covers sodium chloride used for pre-treatment of and deicing road surfaces and for road construction and maintenance applications. Other uses may also be appropriate.

1.2. This specification is applicable for orders in either SI units or inch-pound units. SI and inch-pound units are not necessarily equivalent. Inch-pound units are shown in brackets in the text for clarity, but they are applicable values when the material is ordered.

2. REFERENCED DOCUMENTS

2.1. AASHTO Standard:

T 27, Sieve Analysis of Fine and Coarse Aggregates

2.2. ASTM Standards:

D1429, Standard Test Methods for Specific Gravity of Water and Brine E534, Standard Test Methods for Chemical Analysis of Sodium Chloride

3. CLASSIFICATION

3.1. This specification covers sodium chloride mined from natural deposits, commonly known as rock salt, as well as evaporated from naturally occurring or hydraulically produced brine. The following two types and grades are commonly recognized:

3.1.1. Type I—Used for deicing pavement surfaces or in aggregate stabilization:

3.1.1.1. Grade 1—Standard grading for general use as described in Section 6.1.

3.1.1.2. Grade 2—Special grading as described in Section 6.1.

3.1.2. Type II—Used in aggregate stabilization and applications other than deicing pavements.

3.2. This specification also covers sodium chloride used in the form of brine defined as a liquid saturated with chloride.

© 2023 by the American Association of State Highway and Transportation Officials.

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TS-4c M 143-2 AASHTO

4. ORDERING INFORMATION

4.1. Orders for sodium chloride under this specification shall include the following information as necessary to adequately describe the desired product:

4.1.1. AASHTO designation and year of issue;

4.1.2. Type and grade (if appropriate) of product required;

4.1.3. Quantity required;

4.1.4. Delivery location;

4.1.5. Special requirements (including special grading requirements, packaging size, marking requirements, and special shipping instructions), if required; and

4.1.6. Testing, lot size, and certification, if required.

5. CHEMICAL REQUIREMENTS

5.1. The chemical composition for the sodium chloride ordered shall conform to a minimum of 95 percent sodium chloride (NaCl).

5.2. A current Safety Data Sheet (SDS) is required for the sodium chloride ordered and, as appropriate, the current SDS for anticaking agents or other additives used is also required.

5.3. Brine shall be at a solution concentration of 23.3 percent NaCl by weight.

Note 1—Agencies may allow a variation of the required concentration when considering expected minimum roadway temperatures and performance needs based on the phase diagram shown in Figure X1.1.

6. PHYSICAL REQUIREMENTS

6.1. Grading:

6.1.1. Type I—The grading of Type I sodium chloride, when sampled at the point of delivery and tested in accordance with T 27, shall conform to the requirements of Table 1.

Table 1—Grading Requirements

Sieve Size % Passing

Grade 1 Grade 2

19.0 mm [3/4 in.] — 100

12.5 mm [1/2 in.] 100 —

9.5 mm [3/8 in.] 95 to 100 —

4.75 mm [No. 4] 20 to 95 20 to 100

2.36 mm [No. 8] 10 to 65 10 to 65 600 um [No. 30] 0 to 20 0 to 20

6.1.2. Type II—The grading of Type II sodium chloride shall conform to the requirements of the purchaser to meet the needs for the intended use as noted in Section 4.1.

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TS-4c M 143-3 AASHTO

6.2. Condition:

6.2.1. The sodium chloride shall be delivered to the specified location in a free-flowing and usable condition.

6.2.1.1. Anticaking agents may be specified to prevent stockpiles from crusting over or forming clumps of product.

6.2.1.2. The specifying agency may establish moisture requirements in addition to the other physical requirements.

6.3. Brine:

6.3.1. Sodium chloride brine shall be delivered at a solution concentration of 23.3 percent by weight with a specific gravity of 1.176 when tested in accordance with ASTM D1429, Method D.

Note 2—Agencies may allow a variation of the required concentration when considering expected minimum roadway temperatures and performance needs based on the phase diagram shown in Figure X1.1.

7. SAMPLING AND TESTING

7.1. Sampling Solid Forms of Sodium Chloride:

7.1.1. Lot size shall be as agreed on between the purchaser and supplier at the time of purchase.

7.1.2. Samples shall be taken at the point of delivery.

7.1.3. A minimum of three samples shall be randomly selected from each lot to form a representative composite sample.

7.1.4. Each increment of the composite sample shall be obtained by removing a minimum of 25 mm [1 in.] of material from the surface and obtaining a 500-g [approximately 1-lb] sample of sodium chloride to a depth of at least 150 mm [6 in.]. A sampling tube, sampling thief, or other method that will ensure a representative cross section of the material shall be used. A representative composite sample of the lot shall be the result of thoroughly combining and mixing the individual increments.

7.2. Testing shall comply with the requirements of ASTM E534, unless otherwise specified.

7.3. Rapid methods of analysis may be used to perform quality control or approval testing when permitted by the purchaser and the variability of the source is known.

7.4. Two additional samples shall be taken and tested as described by Sections 7.1 and 7.2, in the event of an initial sample failure of the lot. If both additional samples meet the specification requirements, the lot shall be accepted.

7.5. Sampling Sodium Chloride Brine:

7.5.1. A minimum of three samples shall be selected from each storage tank or truck to form a composite sample.

7.6. Testing the composite sample of brine shall be in accordance with ASTM D1429, Method D.

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TS-4c M 143-4 AASHTO

8. REJECTION

8.1. Sodium chloride that fails to conform to the requirements of this specification may be rejected.

Sodium chloride that is not free-flowing, becomes caked, or is otherwise contaminated may also be rejected, whether it has been tested or not.

8.2. Sodium chloride brine containing clumps of solid sodium chloride that have not gone into solution or other solid contaminants may be rejected.

9. CERTIFICATION

9.1. When specified in the purchase order or contract, a supplier’s certification shall be provided stating that representative samples have been inspected and tested in accordance with this specification and have been found to meet the requirements of the material described in the order.

When specified in the purchase order or contract, a report of the test results shall be provided.

10. PACKAGING AND MARKING

10.1. Sodium chloride in solid form shall be delivered in bags or other containers acceptable to the purchaser. Bulk lots may also be acceptable to the purchaser.

10.2. Each container, tank, or package of sodium chloride shall be identified by the following, unless otherwise specified in the purchase order or contract:

10.2.1. Manufacturer’s name,

10.2.2. Product name, and

10.2.3. Net weight.

10.3. Sodium chloride brine shall include the identification in Section 10.2 for the product prior to it being mixed into brine.

11. KEYWORDS

11.1. Brine; deicing salts; sodium chloride; stabilization.

APPENDIXES

(Nonmandatory Information)

X1. PRODUCTION OF BRINE USING SODIUM CHLORIDE

X1.1. Brine is defined as a liquid that is saturated or nearly full of chloride.

X1.2. Sodium chloride brine is available commercially, and some agencies are producing brine on site using either commercially available production systems or agency-constructed systems.

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TS-4c M 143-5 AASHTO

X1.3. The desired concentration of sodium chloride brine that reflects the lowest freezing point of the solution is 23.3 percent. Figure X1.1 exhibits the phase diagram of sodium chloride brine and the narrow range of effectiveness as the concentration varies from the optimum.

Figure X1.1—Phase Diagram of Sodium Chloride and Calcium Chloride Brine

X1.4. Sodium chloride brine concentration can be adjusted during production by either dilution or reprocessing through the mixing operation to achieve the desired concentration.

X1.5. FHWA-RD-95-202, Manual of Practice for an Effective Anti-Icing Program, provides detailed information about the production of brines.

X1.6. Some agencies include requirements for the addition of a corrosion inhibitor to the brine.

X2. MOISTURE

X2.1. The moisture determination in ASTM E534 may not be appropriate for moisture contents above

0.04 percent.

X2.2. ASTM D2216, Method B, may provide more accurate moisture content for sodium chloride with higher moisture contents.

X2.2.1. The drying time may vary and the method relies on the judgment of the technician to determine when a constant weight is achieved.

X2.2.2. Method B more accurately represents the typical particle size for sodium chloride.

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TS-4c M 143-6 AASHTO

X2.3. Some agencies may establish moisture requirements in addition to the other physical requirements included in Section 6.

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