ASTM C779/C779M-19

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Designation: C779/C779M − 12 C779/C779M − 19
Standard Test Method for
Abrasion Resistance of Horizontal Concrete Surfaces
This standard is issued under the fixed designation C779/C779M; 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.
1. Scope*
1.1 This test method covers three procedures for determining the relative abrasion resistance of horizontal concrete surfaces.
The procedures differ in the type and degree of abrasive force they impart, and are intended for use in determining variations in
surface properties of concrete affected by mixture proportions, finishing, and surface treatment. They are not intended to provide
a quantitative measurement of the length of service that may be expected from a specific surface.
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text, the
inch-pound units are shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall
be used independently of each other.
1.3 The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered as requirements of this 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. )
NOTE 1—Other procedures are available for measuring the abrasion resistance of concrete surfaces in addition to the three procedures contained in this
test method. Consideration should be given to Test Methods C944C944/C944M and C418. The test method most closely representing service conditions
should be used.
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:
C125 Terminology Relating to Concrete and Concrete Aggregates
C418 Test Method for Abrasion Resistance of Concrete by Sandblasting
C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
C944C944/C944M Test Method for Abrasion Resistance of Concrete or Mortar Surfaces by the Rotating-Cutter Method
3. Terminology
3.1 For definitions of terms used in this standard, refer to Terminology C125.
4. Significance and Use
4.1 The three test methods provide simulated abrasion conditions, which can be used to evaluate the effects on abrasion
resistance of concrete, concrete materials, and curing or finishing procedures. They may also be used for quality acceptance of
products and surface exposed to wear. They are not intended to provide a quantitative measurement of length of service.
This test method is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregatesand is the direct responsibility of Subcommittee C09.62 on
Abrasion Testing.
Current edition approved Dec. 1, 2012Oct. 1, 2019. Published December 2012November 2019. Originally approved in 1974. Last previous edition approved in 20102012
as C779 – 05 (2010).C779/C779M–12. DOI: 10.1520/C0779_C0779M-12.10.1520/C0779_C0779M-19.
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’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C779/C779M − 19
4.2 The equipment used by each of these procedures is portable and thus suitable for either laboratory or field testing. The three
procedures determine the relative wear of concrete surfaces as follows:
4.2.1 Procedure A—The revolving-disk machine operates by sliding and scuffing of steel disks in conjunction with abrasive grit.
4.2.2 Procedure B—The dressing-wheel machine operates by impact and sliding friction of steel dressing wheels.
4.2.3 Procedure C—The ball-bearing machine operates by high-contact stresses, impact, and sliding friction from steel balls.
NOTE 2—Diagrams of three machines meeting these specifications are shown in Fig. 1, Fig. 2, and Fig. 3.
PROCEDURE A—REVOLVING DISKS
5. Apparatus
5.1 The function of the apparatus is dependent upon the abrasive action of the flat faces of three 60-mm (2 ⁄8-in.) diameter,
cold-rolled steel revolving disks, each attached to motor-driven vertical shafts which also revolve about a vertical axis. The inside
diameter of the resulting circular and abraded track shall be approximately 150 mm (6 in.) and the outside diameter 275 mm (11
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in.). Crossed slots 90° to each other and cut 5 mm ( ⁄16 in.) deep and 6 mm ( ⁄4 in.) wide are located symmetrically in the abrasive
flat faces.
5.2 The disks are free floating inasmuch as they are self-supporting and are driven transversely along a circular path at 12
rev/min (12 rpm) while being individually turned on their own axis at 280 rev/min (280 rpm). Cups attached at the top of the shaft
of each disk shall be loaded with lead shot to produce a uniform total load of 22 N (5 lbf) on each abrading disk face.
5.3 The abrasive grit shall consist of 250 μ [No. 60] silicon carbide. This is fed from a storage cup mounted on the revolving
circular plate through a 3-mm ( ⁄8-in.) orifice passing through the plate. The flow of abrasive shall be controlled to a rate of 4 to
6 g/min by an adjusting needle located in the orifice. The abrasive falls at the midwidth of the circular abraded track, and midway
between two of the disks.
FIG. 1 Revolving Disks Abrasion Test Machine
The sole source of supply of these machines known to the committee at this time is White Machine Co., 9591 York Alpha Dr., North Royalton, OH 44133; Spirit
Fabricating, Ltd., 9260 Valley View Rd., Macedonia, OH 44056. If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters.
Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend.
C779/C779M − 19
FIG. 2 Dressing Wheel Abrasion Test Machine
FIG. 3 Ball Bearing Abrasion Test Machine
5.4 The micrometer bridge consists of a machine-finished 25-mm (1-in.) rectangular steel bar of at least 300-mm (12-in.), clear
1 1
span supported by a tripod and drilled along its centerline with ten 3-mm ( ⁄8-in.) diameter holes spaced 6-mm ( ⁄4 in.) on center.
C779/C779M − 19
The measuring instrument is a depth micrometre with a needle having an effective depth range of 25 to 50 mm (1 to 2 in.) and
graduated to an accuracy of at least 0.025 mm (0.001 in.).
6. Test Specimen
6.1 For laboratory test purposes, the machine is designed to accommodate approximately 300 by 300-mm (12 by 12-in.) test
specimens. The apparatus is equipped with an adjusting handle linked by a sprocket and chain-drive assembly to the four 25-mm
(1-in.) diameter posts which support the entire rotating abrasion element. This feature permits the abrasion of test panels up to
approximately 100-mm (4-in.) in thickness. A zero adjustment in the height of the abrasion assembly also permits the use of the
apparatus as a portable device for measuring the abrasion resistance on the surfaces in place as well as on test specimens.
7. Procedure
7.1 Prior to the test period, precondition the sample to remove curing compound and surface irregularities by running the
abrasion machine for 5 min, after which the initial measurements shall be taken. Obtain initial measurements to an accuracy of
at least 0.025 mm (0.001 in.) of the test area by taking two series of 20 measurements each. Place the micrometer bridge so that
the line of the second series of readings bisects at right angles to the first series of measurements. In making measurements
subsequent to the abrasion period, take care that the micrometer bridge is placed in precisely the same position in which the
reference measurements were obtained. To ensure this, outline the ends of the positioned micrometer bridge on the surface prior
to making the initial measurements.
7.2 A test period of 30 min generally produces significant wear on most concrete surfaces, but it is recommended to extend the
test period to 60 min, if information on the longtime abrasion resistance is desired.
7.3 In using the device as a portable apparatus, take care in the selection of the areas to be tested. Although the base of the
apparatus is equipped with rubber pads, not only to prevent the apparatus from creeping during the abrasion operation but also to
minimize the effect of slight variations in the level of the test areas. Select test areas with a minimum of variation in level so as
to eliminate the creeping effect.
7.4 Take measurements of depth wear with a micrometer bridge as described in 5.4 to an accuracy of at least 0.025 mm (0.001
in.). Prior to each set of measurements, clean the specimen surface carefully by removing loose particles.
7.5 Make three tests on surfaces representative of the concrete to be evaluated. When wear of the disks reduces the depth of
the slots to less than 1.5 mm ( ⁄16 in.), they shall be replaced. New disk faces shall be subjected to a break-in period of at least
15 min.
8. Interpretation of Results
8.1 The comparison of measurements of average depth of wear of representative surfaces at 30 and 60-min exposure to abrasion
will indicate the relative abrasion resistance of these surfaces.
9. Report
9.1 Report the depth of wear of each surface tested as well as the average obtained on replicate surfaces.
9.2 Record mixture proportions (including cement content and water-cement ratio), specific gravities, grading of fine and coarse
aggregates, Los Angeles abrasion test results, type and amount of material added to freshly placed concrete surface, type and extent
of troweling, curing details, and age of concrete when tested.
PROCEDURE B—DRESSING WHEELS
10. Apparatus
10.1 The function of the apparatus is dependent upon the abrasive action of three sets of steel dressing wheels riding in a circular
path over a horizontal concrete surface. The dressing wheels in each of the three sets of wheels turn freely on a horizontal axle
at the bottom of a free-floating, weighted, vertical steel shaft.
10.2 Each of the three sets of seven dressing wheels are spaced so that each set cuts approximately a 40-mm (1 ⁄2-in.) wide path.
1 1
The machine produces a circular abrasion path of about 140-mm (5 ⁄2-in.) inside diameter and 220-mm (8 ⁄2-in.) outside diameter.
10.3 The apparatus shall consist of a motor-driven spider arrangement turning at 56 rev/min (56 rpm). The motor shall be
mounted on a horizontal plate supported by four screw jacks allowing the motor to be raised and lowered. The spider shall be hung
from the vertical motor shaft. The three vertical shafts shall be mounted in the spider arrangement so that they rotate with the spider
and are free to move up and down in independent thrust-bearing sockets.
10.4 The three shafts shall be fitted with a yoke inside, upon which a series of seven dressing wheels are placed on a horizontal
axle. The mass of each complete dressing wheel assembly as it bears on the concrete surface
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