ASTM C40/C40M-20

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Designation: C40/C40M − 19 C40/C40M − 20 American Association State
Highway and Transportation Officials Standard
AASHTO No.: T 21
Standard Test Method for
Organic Impurities in Fine Aggregates for Concrete
This standard is issued under the fixed designation C40/C40M; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
1.1 This test method covers two procedures for an approximate determination of the presence of injurious organic impurities
in fine aggregates that are to be used in hydraulic cement mortar or concrete. One procedure uses a standard color solution and
the other uses a glass color standard.
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the
two systems may result in non-conformance with the standard.
1.3 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 and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
C33/C33M Specification for Concrete Aggregates
C87/C87M Test Method for Effect of Organic Impurities in Fine Aggregate on Strength of Mortar
C125 Terminology Relating to Concrete and Concrete Aggregates
C702/C702M Practice for Reducing Samples of Aggregate to Testing Size
D75/D75M Practice for Sampling Aggregates
D1544 Test Method for Color of Transparent Liquids (Gardner Color Scale)
3. Terminology
3.1 For definitions of terms used in this test method, refer to Terminology C125.
4. Significance and Use
4.1 This test method is used in making a preliminary determination of the acceptability of fine aggregates with respect to the
requirements of Specification C33/C33M that relate to organic impurities.
4.2 The principal value of this test method is to furnish a warning that injurious amounts of organic impurities may be present.
When a sample subjected to this test produces a color darker than the standard color it is advisable to perform the test for the effect
of organic impurities on the strength of mortar in accordance with Test Method C87/C87M.
5. Apparatus
5.1 Bottles—Colorless glass or plastic graduated bottles, approximately 240 to 470-mL [8 to 16-oz] nominal capacity, equipped
with watertight stoppers or caps, not soluble in the specified reagents. In no case shall the maximum outside thickness of the
This test method is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregates and is the direct responsibility of Subcommittee C09.20 on
Aggregates.
Current edition approved Jan. 1, 2019Jan. 15, 2020. Published February 2019February 2020. Originally approved in 1921. Last previous edition approved in 20162019
as C40/C40M–16.–19. DOI: 10.1520/C0040_C0040M-10.10.1520/C0040_C0040M-20.
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C40/C40M − 20
bottles, measured along the line of sight used for the color comparison, be greater than 63.5 mm [2.5 in.] or less than 38.1 mm
[1.5 in.]. Replace bottles when no longer colorless due to use.
5.2 Standard Color Solution Level—75 mL [2.5 oz (U.S. fluid)],
5.3 Fine Aggregate Level—130 mL [4.5 oz (U.S. fluid)], and
5.4 NaOH Solution Level—200 mL [7 oz (U.S. fluid)].
5.5 Glass Color Standard
5.5.1 Glass standard colors shall be used as described in Table 1 of Test Method D1544.
NOTE 1—A suitable instrument consists of five glass color standards mounted in a plastic holder. Only the glass identified as Gardner Color Standard
No. 11 is to be used as the Glass Color Standard in 10.2.
6. Reagent and Standard Color Solution
6.1 Reagent Sodium Hydroxide Solution (3 %)—Dissolve 3 parts by mass of reagent grade sodium hydroxide (NaOH) in 97
parts of water.
6.2 Standard Color Solution—Dissolve reagent grade potassium dichromate (K Cr O ) in concentrated sulfuric acid (sp gr 1.84)
2 2 7
at the rate of 0.250 g/100 mL of acid. The solution must be freshly made for the color comparison using gentle heat if necessary
to effect solution.
7. Sampling
7.1 The sample shall be selected in general accordance with Practice D75/D75M.
8. Test Sample
8.1 The test sample shall have a mass of about approximately 450 g [1 lb] and be taken from the larger sample in accordance
with Practice C702/C702M.
9. Procedure
9.1 Fill a glass bottle to the approximately
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