ASTM_C_952_-_12.pdf

Designation:C95212Standard Test Method forBond Strength of Mortar to Masonry Units1This standard is issued under the fixed designation C952;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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope*1.1 This test method provides two procedures for measuringbond strength of mortar to masonry units:a crossed brickcouplet tensile test for evaluating mortar-brick bond strengthand a stacked-bond,flexural test for evaluating mortar-concreteblock bond strength.1.2 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 This standard does not purport to address the safetyconcerns,if any,associated with its use.It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.2.Referenced Documents2.1 ASTM Standards:2C67 Test Methods for Sampling and Testing Brick andStructural Clay TileC90 Specification for Loadbearing Concrete Masonry UnitsC129 Specification for Nonloadbearing Concrete MasonryUnitsC140 Test Methods for Sampling and Testing ConcreteMasonry Units and Related UnitsC270 Specification for Mortar for Unit MasonryC780 Test Method for Preconstruction and ConstructionEvaluation of Mortars for Plain and Reinforced UnitMasonryC1072 Test Methods for Measurement of Masonry FlexuralBond StrengthC1437 Test Method for Flow of Hydraulic Cement MortarE518 Test Methods for Flexural Bond Strength of Masonry3.Significance and Use3.1 These procedures are useful for research into bondstrength of masonry.They are not intended to predict the bondstrength of commercial masonry construction.The bondstrength in commercially built structures is determined bymany factors beyond the characteristics of mortar,masonryunits,and the procedures of this test method.NOTE1The crossed-brick couplets method measures a direct tensilestrength of the bond between the mortar and masonry unit.It does notdetermine the flexural strength of the unit mortar assembly.Other testmethods may be more appropriate for determining the flexural bondstrength between mortar and masonry units.These include Test MethodsC1072 and Test Methods E518.PREPARATION AND TESTING OF FRESH MORTAR4.Preparation of Mortar4.1 Proportion mortar materials by weights equivalent tovolume proportions to be used in prism construction.Use unitweights for individual materials as given in SpecificationC270.Sand shall be permitted to be used in a damp loosecondition,provided that moisture content of sand is determinedwith reference to the oven-dried condition and batch propor-tions are adjusted accordingly.Record weight of ingredients(including water)added to the batch of mortar.4.2 Mix mortar in a mechanical paddle-type mortar mixer.Time periods referenced below are measured from when waterand cementitious materials are combined.4.2.1 Add an estimated amount of water to the mortar toachieve the desired consistency(Note 2).Mix mortar for threeminutes and determine consistency.If the desired consistencyis specified by flow determine it in accordance with TestMethod C1437.If the desired consistency is specified as initialcone penetration,determine it in accordance with Test MethodC780.Once consistency is recorded,return the material used tomeasure the consistency to the mixer.If the consistency iswithin the desired range,continue mixing the batch for anadditional two minutes.If the consistency is less than thedesired range,add water to the batch and mix for one minuteand determine consistency.Once consistency is recorded,1This test method is under the jurisdiction of ASTM Committee C15 onManufactured Masonry Units and is the direct responsibility of SubcommitteeC15.04 on Research.Committee E-6 maintains a continued interest in thesepractices and will make use of them in the future.Current edition approved June 1,2012.Published July 2012.Originally approvedin 1959.Last previous edition approved in 2009 as C952 02(2009).DOI:10.1520/C0952-12.2For 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 return the material used to measure consistency to the mixer.Ifthe consistency is within the desired range,continue mixing thebatch for one minute.NOTE2Workable consi