ASTM_C_944_-_C_944M_-_12.pdf

Designation:C944/C944M12Standard Test Method forAbrasion Resistance of Concrete or Mortar Surfaces by theRotating-Cutter Method1This standard is issued under the fixed designation C944/C944M;the number immediately following the designation indicates the yearof 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 a procedure for determining theresistance of either concrete or mortar to abrasion.This testmethod is similar to Procedure B of Test Method C779/C779M.1.2 The values stated in SI units or inchpound units are tobe regarded separately as standard.The values stated in eachsystem may not be exact equivalents;therefore,each systemshall be used independently of the other.Combining valuesfrom the two systems may result in nonconformance with thestandard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility 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 Documents2.1 ASTM Standards:2C42/C42M Test Method for Obtaining and Testing DrilledCores and Sawed Beams of ConcreteC125 Terminology Relating to Concrete and Concrete Ag-gregatesC418 Test Method for Abrasion Resistance of Concrete bySandblastingC779/C779M Test Method for Abrasion Resistance of Hori-zontal Concrete Surfaces3.Terminology3.1 For definitions of terms used in this standard,refer toTerminology C125.4.Significance and Use4.1 This test method gives an indication of the relative wearresistance of mortar and concrete based on testing of cored orfabricated specimens.This test method has been successfullyused in the quality control of highway and bridge concretesubject to traffic.Primarily intended for use on the top ends of152-mm 6-in.diameter concrete cores,mortar specimens,orother samples of concrete of insufficient test area to permit theconduct of tests by Test Method C418 or C779/C779M,thistest method is also applicable on concrete surfaces in place bymeasuring the abrasion loss as described in Section 10,Procedure B,of Test Method C779/C779M.5.Apparatus5.1 Abrasion DeviceA drill press or similar device with achuck capable of holding and rotating the abrading cutter at aspeed of 200 r/min and exerting a force of either a normal loadof 98 6 1 N 22 6 0.2 lbf or a double load of 197 6 2 N 446 0.4 lbf on the test specimen surface.Fig.1 shows acommercial drill press and Fig.2 illustrates details of therotating cutter.The difficulty in maintaining a constant load onthe abrading cutter when using the lever,gear,and springsystem of a drill press has been eliminated by placing thedesired load directly upon the spindle that turns the cutter.Themachine consists essentially of a frame that supports the drivemotor,stepped pulley,and spindle.A clamping device to holdthe specimen is built into the base.5.2 Rotating CutterA rotating cutter similar to that shownin 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 1.25in.diameter washers are mounted.The washers as receivedshall be stacked and locked on a bolt for the purpose ofreducing 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 suchthat individual dressing wheels are free to turn independently.The overall diameter of the cutter or the diameter of thecircular area abraded is 82.5 mm 314in.Care shall be takento achieve constant contact between the rotating cutter and theentire test surface of the sample.This can be better accom-plished if the cutters have a swivel connection allowing somevertical movement.If the dressing wheels have one rounded1This test method is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregatesand is the direct responsibility of SubcommitteeC09.62 on Abrasion Testing.Current edition approved Dec.1,2012.Published December 2012.Originallyapproved in 1980.Last previous edition approved in 2005 as C944 99(2005)1.DOI:10.1520/C0944_C0944M-12.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 edge,they shall be mounted with the rounded edge toward thevertical shaft.The individual grinding wheel dressers on thehorizontal shaft of the cutter shall be repositioned whenever achange in the diameter of the outer cutters becomes apparent.This is accompl