1、Designation:C114892a(Reapproved 2014)Standard Test Method forMeasuring the Drying Shrinkage of Masonry Mortar1This standard is issued under the fixed designation C1148;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last
2、revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the measurement of unre-strained drying shrinkage of masonry mortars.1.2 This test method is applicable
3、to Specification C270Type N,Type S,and Type M mortars under the property orproportion specifications.Due to the tendency to damage lowerstrength specimens during demolding,it is not applicable tolower strength mortars,such as Type O mortars.1.3 This test method is intended for research purposes only
4、.1.4 The values stated in SI units are to be regarded asstandard.The values given in parentheses are mathematicalconversions to inch-pound units that are provided for informa-tion only and are not considered standard.1.5 This standard does not purport to address all of thesafety concerns,if any,asso
5、ciated 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:2C109/C109M Test Method for Compressive Strength ofHydraulic
6、 Cement Mortars(Using 2-in.or 50-mm CubeSpecimens)C157/C157M Test Method for Length Change of HardenedHydraulic-Cement Mortar and ConcreteC270 Specification for Mortar for Unit MasonryC305 Practice for Mechanical Mixing of Hydraulic CementPastes and Mortars of Plastic ConsistencyC490 Practice for Us
7、e ofApparatus for the Determination ofLength Change of Hardened Cement Paste,Mortar,andConcreteC511 Specification for Mixing Rooms,Moist Cabinets,Moist Rooms,and Water Storage Tanks Used in theTesting of Hydraulic Cements and ConcretesC778 Specification for Sand3.Significance and Use3.1 The drying s
8、hrinkage of mortar as determined by thistest method is a measure of the decrease in length of testspecimens under controlled drying conditions,after an initialperiod of moist curing.3.2 Since test specimens are not completely unrestrainedduring the initial period of moist curing,measurements ofdryin
9、g shrinkage by this test method are most useful forcomparative purposes rather than as absolute values.3.3 The drying shrinkage of unrestrained laboratory testedmortar samples is different from that experienced in a masonrywall where influences include restraint,masonry unitabsorption,ambient temper
10、ature and humidity,thickness ofjoint,length of continuous wall,etc.4.Apparatus4.1 Scales and Weights,Glass Graduates,and LengthComparator,conforming to requirements of SpecificationC490.4.2 Molds(for test specimens),providing for 25 by 25 by285-mm(1 by 1 by 11.25-in.)prisms having an effective gagel
11、ength of 250 mm(10 in.),and conforming to the requirementsof Specification C490.4.3 Studs,conforming to the requirements of SpecificationC490.4.4 Tamper and Demolding Apparatus,conforming to re-quirements of Test Method C157/C157M.4.5 Trowel,having a straight edged steel blade 100 to 150mm(4 to 6 in
12、.)in length.5.Temperature and Humidity5.1 Molding RoomThe temperature of the molding room,dry materials,mixing water,and the relative humidity of the airin the molding room shall conform to the requirements ofSpecification C490.1This test method is under the jurisdiction ofASTM Committee C12 on Mort
13、arsand Grouts for Unit Masonry and is the direct responsibility of SubcommitteeC12.02 on Research and Methods of Test.Current edition approved Dec.15,2014.Published December 2014.Originallyapproved in 1990.Last previous edition approved in 2008 as C1148 92a(2008).DOI:10.1520/C1148-92AR14.2For refere
14、nced 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohoc
15、ken,PA 19428-2959.United States1 5.2 Moist Storage FacilityThe temperature and humidityof the air in the moist storage facility shall conform to therequirements of Specification C511.5.3 Drying Room and ControlsThe drying room andcontrols shall conform to the requirements of Test MethodC157/C157M.6.
16、Test Specimens6.1 Number of Test Specimens:6.1.1 Make five test specimens.Although the number of testspecimens may consist of five specimens made from a singlebatch of mortar,it is preferable that 15 specimens be made withfive specimens being made from each of three batches,witheach batch being made on a different day.6.2 Preparation of Test Specimens:6.2.1 Proportioning Mortar MaterialsMeasure materialsfor testing according to the procedures outlined in SpecificationC270 for the determination o
