ASTM_C_349_-_14.pdf

Designation:C34914Standard Test Method forCompressive Strength of Hydraulic-Cement Mortars(Using Portions of Prisms Broken in Flexure)1This standard is issued under the fixed designation C349;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This test method covers the determination of the com-pressive strength of hydraulic-cement mortars,using for thetest specimens portions of prisms made and broken in flexurein accordance with Test Method C348.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 Values in SI units shall be obtained by measurement inSI units or by appropriate conversion,using the Rules forConversion and rounding given in Standard IEEE/ASTM SI10,of measurements made in other units.1.4 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.(WarningFreshhydraulic cementitious mixtures are caustic and may causechemical burns to skin and tissue upon prolonged exposure.2)2.Referenced Documents2.1 ASTM Standards:3C109/C109M Test Method for Compressive Strength ofHydraulic Cement Mortars(Using 2-in.or 50-mm CubeSpecimens)C348 Test Method for Flexural Strength of Hydraulic-Cement MortarsC670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsIEEE/ASTM SI 10 Standard for Use of the InternationalSystem of Units(SI):The Modern Metric System3.Significance and Use3.1 This method provides a means of obtaining compressivestrength values from the same specimens previously used forflexural strength determinations by Test Method C348.Thecompressive strength values are for reference purposes,and notas substitutes for values obtained by Test Method C109/C109M for cement acceptance.4.Apparatus4.1 Bearing PlatesThe bearing plates shall be 25 mm inthickness and shall be made of a hard metal.The surfaces of thebearing plates that are placed in contact with the specimensshall be 40.0 6 0.1-mm by 50.8-mm rectangles,with the50.8-mm dimension at right angles to the longitudinal axis ofthe prism.The bearing plate surfaces in contact with thespecimen shall have a Rockwell hardness of not less than 60HRC.These surfaces shall not depart from plane surfaces bymore than 0.01 mm when the plates are new and shall bemaintained within a permissible variation of 0.03 mm.4.2 Device for Aligning Bearing PlatesAdevice for align-ing the bearing plates to ensure the proper location of the upperplate with reference to the lower plate is shown in Fig.1.If theupper bearing plate does not have free movement within thealigning plates,these shall be separated from the bottom plateby insertion of 0.05-mm shims on each side of the bottombearing plate,and the two 6-mm pins in the upper bearing platefiled down just sufficiently to permit free up and downmovement in the slots at the top of the aligning plates.4.3 Testing MachineThe testing machine shall conform tothe requirements prescribed in Test Method C109/C109M,except that the testing machine shall be of the hydraulic type.5.Test Specimens5.1 Both portions from each prism broken in flexure shall beused for compression testing,except that the broken portions ofprisms selected for the compression test shall have a length ofnot less than 65 mm and shall be free of cracks,chippedsurfaces,or other obvious defects.6.Procedure6.1 Determination of Compressive StrengthDuring theinterval between flexure tests of the prisms and testing the1This test method is under the jurisdiction of ASTM Committee C01 on Cementand is the direct responsibility of Subcommittee C01.27 on Strength.Current edition approved Dec.1,2014.Published January 2015.Originallyapproved in 1954.Last previous edition approved in 2008 as C349 08.DOI:10.1520/C0349-14.2See the section on Safety,Manual of Cement Testing,Annual Book of ASTMStandards,Vol 04.01.3For 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 FIG.1 Bearing Plates and Bearing Plate Aligning Device for Testing 40 by 40 by 160-mm Mortar Prisms as Modified CubesC349 142 broken portions as modified cubes,cover the specimens for the24-h test with waterproof plastic and completely immerse allother specimens in water at a temperature of 23 6 2