Designation: C 944 – 99 (Reapproved 2005) Standard Test Method for Abrasion Resistance of Concrete or Mortar Surfaces by the Rotating-Cutter Method 1 This standard is issued under the fixed designation C 944; 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 (e) indicates an editorial change since the last revision or reapproval. 1. Scope 1.1 This test method covers a procedure for determining the resistance of either concrete or mortar to abrasion. This test method is similar to Procedure B of Test Method C 779/ C 779M. 1.2 The values stated in 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 appro- priate safety and health practices and determine the applica- bility of regulatory limitations prior to use. 2. Referenced Documents 2.1 ASTM Standards: 2 C 42 Test Method for Obtaining and Testing Drilled Cores and Sawed Beams of Concrete C 418 Test Method for Abrasion Resistance of Concrete by Sandblasting C 779/C 779M Test Method for Abrasion Resistance of Horizontal Concrete Surfaces 3. Significance and Use 3.1 This test method gives an indication of the relative wear resistance of mortar and concrete based on testing of cored or fabricated specimens. This test method has been successfully used in the quality control of highway and bridge concrete subject to traffic. Primarily intended for use on the top ends of 152-mm [6-in.] diameter concrete cores, mortar specimens, or other samples of concrete of insufficient test area to permit the conduct of tests by Test Method C 418 or C 779/C 779M, this test method is also applicable on concrete surfaces in place by measuring the abrasion loss as described in Section 9, Proce- dure B, of Test Method C 779/C 779M. 4. Apparatus 4.1 Abrasion Device—A drill press or similar device with a chuck capable of holding and rotating the abrading cutter at a speed of 200 r/min and exerting a force of either a normal load of 98 6 1 N [22 6 0.2 lbf] or a double load of 197 6 2 N [44 6 0.4 lbf] on the test specimen surface. Fig. 1 shows a commercial drill press and Fig. 2 illustrates details of the rotating cutter. The difficulty in maintaining a constant load on the abrading cutter when using the lever, gear, and spring system of a drill press has been eliminated by placing the desired load directly upon the spindle that turns the cutter. The machine consists essentially of a frame that supports the drive motor, stepped pulley, and spindle. A clamping device to hold the specimen is built into the base. 4.2 Rotating Cutter—A rotating cutter similar to that shown in Fig. 2 and Fig. 3 shall be used in which 22 37.5 mm [1.5 in.] diameter dressing wheels and 24 25.4 to 31.75 mm [1 to 1.25 in.] diameter washers are mounted. The washers as received shall be stacked and locked on a bolt for the purpose of reducing their diameter to the specified range to avoid restrict- ing abrasion of the concrete by the washers. Cutter assembly, including washers, shall be locked onto horizontal rods such that individual dressing wheels are free to turn independently. The overall diameter of the cutter or the diameter of the circular area abraded is 82.5 mm [3 1 /4 in.]. Care shall be taken to achieve constant contact between the rotating cutter and the entire test surface of the sample. This can be better accom- plished if the cutters have a swivel connection allowing some vertical movement. If the dressing wheels have one rounded edge, they shall be mounted with the rounded edge toward the vertical shaft. The individual grinding wheel dressers on the horizontal shaft of the cutter shall be repositioned whenever a change in the diameter of the outer cutters becomes apparent. This is accomplished by reversing each set of dressing wheels to bring the smaller diameter cutters toward the vertical shaft. 1 This test method is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregates and is the direct responsibility of Subcommittee C09.62 on Abrasion Testing of Concrete. Current edition approved July 10, 1999. Published September 1999. Originally approved in 1980. Last previous edition approved in 1990 as C 944 – 90a. 2 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. 1 Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States. Copyright by ASTM Int'l (all rights reserved); Reproduction authorized per License Agreement with Kathe Hooper (ASTMIHS Account); Mon Jun 13 12:05:34 EDT 2005 Copyright ASTM International Provided by IHS under license with ASTM Licensee=Purdue University/5923082001 Not for Resale, 09/10/2007 13:49:12 MDT No reproduction or networking permitted without license from IHS --`,,``,,,,`,```,`,`,`,,````,,-`-`,,`,,`,`,,`---