ASTM C143/C143M-20

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it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C143/C143M − 15a C143/C143M − 20
Standard Test Method for
Slump of Hydraulic-Cement Concrete
This standard is issued under the fixed designation C143/C143M; 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 determination of slump of hydraulic-cement concrete, both in the laboratory and in the field.
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text, the SI units
are shown in brackets. The values stated in each system mayare not benecessarily exact equivalents; therefore, to ensure
conformance with the standard, each system shall be used independently of the other. Combiningother, and values from the two
systems may result in non-conformance with the standard.shall not be combined.
1.3 The text of this standard references refers to notes and footnotes whichthat provide explanatory material. These notes and
footnotes (excluding those in tables and figures) shall not be considered as requirements of thethis standard.
1.4 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use. (Warning—Fresh hydraulic cementitious mixtures are caustic and may cause
chemical burns to skin and tissue upon prolonged exposure. )
1.5 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.
2. Referenced Documents
2.1 ASTM Standards:
C31/C31M Practice for Making and Curing Concrete Test Specimens in the Field
C138/C138M Test Method for Density (Unit Weight), Yield, and Air Content (Gravimetric) of Concrete
C172C172/C172M Practice for Sampling Freshly Mixed Concrete
C173/C173M Test Method for Air Content of Freshly Mixed Concrete by the Volumetric Method
C231C231/C231M Test Method for Air Content of Freshly Mixed Concrete by the Pressure Method
C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
D638 Test Method for Tensile Properties of Plastics
3. Summary of Test Method
3.1 A sample of freshly mixed concrete is placed and compacted by rodding in a mold shaped as the frustum of a cone. The
mold is raised, and the concrete allowed to subside. The vertical distance between the original and displaced position of the center
of the top surface of the concrete is measured and reported as the slump of the concrete.
4. Significance and Use
4.1 This test method is intended to provide the user with a procedure to determine slump of plastic hydraulic-cement concretes.
NOTE 1—This test method was originally developed to provide a technique to monitor the consistency of unhardened concrete. Under laboratory
This test method is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregates and is the direct responsibility of Subcommittee C09.60 on
Testing Fresh Concrete.
Current edition approved Dec. 15, 2015June 1, 2020. Published February 2016July 2020. Originally approved in 1922. Last previous edition approved in 2015 as
C143/C143M – 15.C143/C143M – 15a. DOI: 10.1520/C0143_C0143M-15A10.1520/C0143_C0143M-20.
Section on Safety Precautions, Manual of Aggregate and Concrete Testing, Annual Book of ASTM Standards, Vol. 04.02.Section on Safety Precautions, Manual of
Aggregate and Concrete Testing, Annual Book of ASTM Standards, Vol 04.02.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’sstandard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
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C143/C143M − 20
conditions, with strict control of all concrete materials, the slump is generally found to increase proportionally with the water content of a given concrete
mixture, and thus to be inversely related to concrete strength. Under field conditions, however, such a strength relationship is not clearly and consistently
shown. Care should therefore be taken in relating slump results obtained under field conditions to strength.
4.2 This test method is considered applicable to plastic concrete having coarse aggregate up to 1 ⁄2 in. [37.5 mm] in size. If the
coarse aggregate is larger than 1 ⁄2 in. [37.5 mm] in size, the test method is applicable when it is performed on the fraction of
concrete passing a 1 ⁄2-in. [37.5-mm] sieve, with the larger aggregate being removed in accordance with the section titled
“Additional Procedure for Large Maximum Size Aggregate Concrete” in Practice C172C172/C172M.
4.3 This test method is not considered applicable to non-plastic and non-cohesive concrete.
NOTE 2—Concretes having slumps less than ⁄2 in. [15 mm] may not be adequately plastic and concretes having slumps greater than about 9 in. [230
mm] may not be adequately cohesive for this test to have significance. Caution should be exercised in interpreting such results.
5. Apparatus
5.1 Mold—The test specimen shall be formed in a mold made of metal or plastic not readily attacked by the cement paste. The
mold shall be sufficiently rigid to maintain the specified dimensions and tolerances during use, resistant to impact forces, and shall
be non-absorbent. Metal molds shall have an average thickness of not less than 0.060 in. [1.5 mm] with no individual thickness
measurement less than 0.045 in. [1.15 mm]. Plastic molds shall be ABS plastic or equivalent (Note 3) with a minimum average
wall thickness of 0.125 in. [3 mm], with no individual thickness measurement less than 0.100 in. [2.5 mm]. The manufacturer or
supplier shall certify the materials used in mold construction are in compliance with the requirements of this test method. The mold
shall be in the form of the lateral surface of the frustum of a cone with the base 8 in. [200 mm] in diameter, the top 4 in. [100
mm] in diameter, and the height 12 in. [300 mm]. Individual diameters and heights shall be within 6 ⁄8 in. [3 mm] of the prescribed
dimensions. The base and the top shall be open and parallel to each other and at right angles to the axis of the cone. The mold
shall be provided with foot pieces and handles similar to those shown in Fig. 1. The mold shall be constructed without a seam.
The interior of the mold shall be relatively smooth and free from projections. The mold shall be free from dents, deformation, or
adhered mortar. A mold which clamps to a nonabsorbent base plate is acceptable instead of the one illustrated, provided the
clamping arrangement is such that it can be fully released without movement of the mold and the base is large enough to contain
all of the slumped concrete in an acceptable test.
NOTE 3—ABS (Acrylonitrile Butadiene Styrene) plastic exhibits the following minimum mechanical properties:
Dimensional Units
1 1 1 1
in. ⁄16 ⁄8 ⁄2 1 3 3 ⁄8 4 8 12
mm [2] [3] [15] [25] [75] [80] [100] [200] [300]
FIG. 1 Mold for Slump Test
C143/C143M − 20
Tensile modulus of elasticity, 320 000 psi [2206 MPa]
at 73 °F [23 °C]
Tensile strength (Test Method D638) 5670 psi [39 MPa]
Percent Elongation at Break, 40%
at 73 °F [23 °C]
Percent Elongation at Break, 40 %
at 73 °F [23 °C]
5.1.1 Check and record conformance to the mold’smold’s specified dimensions when it is purchased or first placed in service
and at least annually thereafter. To measure the top diameter, bottom diameter, and height, perform two measurements for each,
approximately 90° apart, and record the results of each measurement. To verify mold thickness, perform two measurements
approximately 180° apart at 1 6 ⁄2 in. [25 6 10 mm] from the top of the mold, two measurements approximately 180° apart at
1 6 ⁄2 in. [25 6 10 mm] from the bottom of the mold, and calculate the average of the four measurements.
5 1
5.2 Tamping Rod—A round, smooth, straight steel rod, with a ⁄8 in. [16 mm] 6 ⁄16 in. [2 mm] diameter. The length of the
tamping rod shall be at least 4 in. [100 mm] greater than the depth of the mold in which rodding is being performed, but not greater
than 24 in. [600 mm] in overall length (Note 4). The rod shall have the tamping end or both ends rounded to a hemispherical tip
of the same diameter as the rod.
NOTE 4—A rod length of 16 in. [400 mm] to 24 in. [600 mm] meets the requirements of the following: Practice C31/C31M, Test Method
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