1、Designation: C 1357 05Standard Test Methods forEvaluating Masonry Bond Strength1This standard is issued under the fixed designation C 1357; 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 pare
2、ntheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.NoteAnnex A1 and Annex A2 were corrected and the year date changed on April 14, 2005.INTRODUCTIONBond strength between mortar and masonry units is an important
3、physical property of masonry.Increased bond strength provides greater resistance to loads and to cracking. Bond strength thereforeinfluences structural integrity and serviceability.1. Scope*1.1 These test methods cover the evaluation of flexural bondstrength, normal to the bed joints, of masonry bui
4、lt of manu-factured masonry units, as determined in accordance with TestMethod C 1072. Sampling and testing procedures are refer-enced, and terms are defined. Two different test methods arespecified, each for a different purpose:1.1.1 The first test method is the “Test Method forLaboratory-Prepared
5、Specimens.” Its purpose is to compare thebond strengths (under the given conditions) of masonry mor-tars. It could be used, for example, to check the quality ofmortar products after production, or to indicate the bondstrength (under the given conditions) of a mortar productwithout requiring the prod
6、uct to be tested in combination withmany different units. It is not intended to represent fieldconditions. It uses standard concrete masonry units. Mortarsare batched by weight equivalents of volume proportions andare mixed to a prescribed flow. Prisms are constructed using ajig and are bag-cured.NO
7、TE 1Standard fired clay masonry units are under development butare not now available. When their development is complete, they will beincorporated into these test methods.1.1.2 The second test method is the “Test Method forField-Prepared Specimens.” Its purpose is to evaluate the bondstrength (under
8、 the given conditions) of a particular unit-mortarcombination, either for preconstruction evaluation of materialsor for quality control purposes during construction. Mortars arebatched conventionally, and the flow is not prescribed. Prismsare constructed conventionally (no jig) and are bag-cured.1.1
9、.3 The two test methods are not consistent, nor are theyintended to be. They are intended to be used for two differentpurposes. To make this clear, the two methods are presentedseparately.1.1.4 Appendix X1 suggests two possible criteria for assess-ing the bond strength values obtained using these te
10、st methods.These possible evaluation criteria are given for illustration onlyand are not mandatory.1.2 The values stated in inch-pound units are to be regardedas the standard. The values given in parentheses are forinformation only.1.3 This standard does not purport to address all of thesafety conce
11、rns, 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:2C67 Test Methods of Sampling and Testing
12、 Brick andStructural Clay TileC 140 Test Methods of Sampling and Testing ConcreteMasonry Units and Related UnitsC 230 Specification for Flow Table for Use in Tests ofHydraulic CementC 270 Specification for Mortar for Unit MasonryC 780 Test Method for Preconstruction and ConstructionEvaluation of Mor
13、tars for Plain and Reinforced UnitMasonryC 1072 Test Method for Measurement of Masonry FlexuralBond Strength1These test methods are under the jurisdiction of ASTM Committee C15 onManufactured Masonry Units and are the direct responsibility of SubcommitteeC15.05 on Masonry Assemblies.Current edition
14、approved April 14, 2005. Published April 2005. Originallyapproved in 1996. Last previous edition approved in 2004 as C 1357 04a.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informatio
15、n, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.C 1437 Test Method for Flow of Hydraulic Cement Mort
16、ar2.2 Other Documents:Building Code Requirements for Masonry Structures (ACI530-99/ASCE 5-99/TMS 402-99)3NBS Handbook 9143. Terminology3.1 Definitions:3.1.1 lot, nmaterial of a given quantity of a single type,grade, class, and brand and practically of the same nominalsize, color range, texture, and
17、composition produced by asingle source by virtually the same process and under essen-tially the same conditions.3.1.2 sample, na number of specimens selected at randomfrom a lot in which every specimen has an equal chance ofbeing selected in every trial.3.1.2.1 DiscussionIt is virtually impossible t
18、o select asample at random by exercise of human judgment alone. Toavoid bias, it is necessary to select a random sample using anartificial or mechanical device such as a table of randomnumbers or a random number generator.3.1.3 specimen, nan individual piece of randomly se-lected material in a sampl
19、e.TEST METHOD FOR LABORATORY-PREPAREDSPECIMENS4. Summary of Test Method4.1 This test method is for evaluating the flexural bondstrength (under the given conditions) of masonry built ofstandard masonry units, as determined in accordance with TestMethod C 1072. It uses standard concrete masonry units.
20、Mortars are batched by weight equivalents of volume propor-tions and are mixed to a prescribed flow. Prisms are con-structed using a jig and are bag-cured.5. Significance and Use5.1 This test method is intended for use in comparing thebond strengths (under the given conditions) of masonry mor-tars,
21、as determined in accordance with Test Method C 1072.5.2 This test method could be used, for example, to checkone aspect of the quality of mortar products after production, orto indicate the bond potential of a mortar product withoutrequiring the product to be tested in combination with manydifferent
22、 units.5.3 This test method uses controlled conditions of fabrica-tion and curing that are not intended to represent fieldconditions.5.4 This test method uses standard concrete masonry units.Mortars are batched by weight equivalents of volume propor-tions and are mixed to a prescribed flow. Prisms a
23、re con-structed using a jig and are bag-cured.5.5 Flexural bond strength determined by this test methodshall not be interpreted as the flexural bond strength of a wall(because standard units are not used for wall construction), norshall it be interpreted as an indication of extent of bond forpurpose
24、s of water permeability evaluation.6. Apparatus6.1 Prism Fabrication Jig, as described in Annex A2 andshown in Fig. A2.1.6.2 Mortar Joint Template, as described in Annex A2 andshown in Fig. A2.2.6.3 Drop Hammer, as described in Annex A2 and shown inFig. A2.36.4 Mechanical Paddle-Type Mortar Mixer, o
25、f no less than0.6 ft3(18L) capacity.6.5 Flow Table, Flow Mold, and Caliper, conforming to therequirements of Specification C 230.6.6 Cone Penetrometer, Unit Measure, Straightedge,Spatula, Tapping Stick, and Spoon, conforming to the require-ments of Test Method C 780.6.7 Bond Strength Test Apparatus,
26、 conforming to the re-quirements of Test Method C 1072.7. Materials7.1 Select representative samples of each lot of mortarmaterials. Each sample of material shall be of sufficientquantity to build a set of test prisms. Use standard concretemasonry units meeting the requirements of Annex A1.7.2 Morta
27、r materials (including water) shall be at an equi-librium temperature with laboratory air (see Section 8).8. Temperature and Humidity8.1 Maintain the temperature of laboratory air in the vicinityof mixing of mortar, fabrication of specimens, curing, andtesting of specimens at 24 6 9C (75 6 16F)8.2 M
28、aintain the relative humidity of laboratory air in thevicinity of mixing of mortar, fabrication of specimens, andtesting of specimens between 30 and 80 %.9. Procedure9.1 Fabricate a set of test prisms (any convenient number ofprisms) containing a total of not less than 15 nor more than 30mortar join
29、ts. Each prism shall have no more than 5 joints.9.1.1 Proportion mortar materials by weights equivalent tovolume proportions to be used in prism construction. Use unitweights for individual materials as given in SpecificationC 270. Sand shall be permitted to be used in a damp loosecondition, provide
30、d 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.9.1.2 Mix mortar in a mechanical paddle-type mortar mixer.Time periods referenced below
31、are measured from when waterand cementitious materials are combined.9.1.2.1 For standard concrete masonry units, add an esti-mated amount of water to the mortar to achieve a flow of 1276 3 determined in accordance with Test Method C 1437. Mixmortar for three minutes and determine flow. Once flow isr
32、ecorded, return the material used to measure flow to the mixer.If the flow is 127 6 3, continue mixing the batch for anadditional two minutes. If the flow is less than 124, add waterto the batch, mix for one minute, and determine flow. Once3Available from Masonry Standards Joint Committee.4Natrella,
33、 M. G., Experimental Statistics, National Bureau of Standards Hand-book 91, U.S. Government Printing Office, August 1, 1963, pp. 214.C1357052flow is recorded, return the material used to measure flow tothe mixer. If the flow is 1276 3, continue mixing the batch forone minute.9.1.2.2 If after the one
34、-time addition of water the flow is not127 6 3, discard the batch.9.1.2.3 If the measured flow exceeds 130 at any time,discard the batch.9.1.3 Immediately after mixing the mortar, determine itsinitial cone penetration in accordance with Test Method C 780.Determine the cone penetration of the mortar
35、every 15 6 5minutes. If the cone penetration is less than 80 % of its initialvalue, discard the remaining portion of the mortar withoutconstructing additional mortar joints.9.1.4 Use standard concrete masonry units as defined inAnnexA1. Clean the bed surface of units of dirt, loose sand, orother con
36、taminants.9.1.5 Fabricate prism specimens as described in Annex A2.9.1.6 Cure prism specimens in accordance with Annex A2.9.2 Conduct bond-wrench tests on prism specimens.9.2.1 Test the prisms in the same facility where they werebuilt.9.2.2 Test masonry prisms in accordance with the require-ments of
37、 Test Method C 1072 except as otherwise provided inthis test method.NOTE 2When test ages other than 28 days are specified, the generalrelationship between the strength at the specified test age and that at 28days is generally established by test. That relationship may vary withdifferent materials an
38、d curing conditions.10. Report10.1 Identify mortar materials and units tested, including asapplicable the manufacturers name, brand name, type, grade,source of sample, date sampled, and date tested.10.2 List unit dimensions, number of joints per prism, andnumber of prisms per set of specimens.10.3 I
39、nclude the following in the report:10.3.1 Weight of ingredients (including water) added to thebatch of mortar.10.3.2 Flow or cone penetrometer reading of mortar used toconstruct prisms.10.3.3 Flexural bond strength test results for each joint ofthe test specimens. Mean, standard deviation, and test
40、age foreach set of test specimens.11. Precision and Bias11.1 PrecisionPublished data are not available for within-laboratory variability of this test method. Published data(Hedstrom,5Melander6) obtained under conditions almostidentical with those of this test method show within-batchcoefficients of
41、variation varying between 10 % and 25 % for30-joint samples of selected portland cement-lime mortars andmasonry cement mortars. Because only one sample of eachmortar was tested in each laboratory, sufficient data are notavailable to establish repeatability for this test method. Inter-laboratory test
42、ing is now planned to determine the reproduc-ibility of this test method. It is the intent of this committee todevelop precision values within 5 years from the date ofissuance of this test method.11.2 BiasNo information can be presented on the bias ofthis test method because no test having an accept
43、ed referencevalue is available.TEST METHOD FOR FIELD-PREPARED SPECIMENS12. Summary of Test Method12.1 This test method is for evaluating the flexural bondstrength (under the given conditions) of masonry built ofconventional masonry units, as determined in accordance withTest Method C 1072. Mortars a
44、re batched conventionally, andtheir flow is not prescribed. Prisms are constructed convention-ally (no jig) and are bag-cured.13. Significance and Use13.1 This test method is intended for evaluation of flexuralbond strength (under the given conditions) between mortar andunits, as determined in accor
45、dance with Test Method C 1072.13.2 The purpose of this test method is to evaluate the bondstrength (under the given conditions) of a particular unit-mortarcombination, either for preconstruction evaluation of materialsor for quality control purposes during construction. Precon-struction field tests
46、may be used to provide information on thepotential performance of a mortar-unit combination under fieldconditions of fabrication and workmanship (but not curing).Construction field tests may be used as a quality controlmeasure to ensure that performance criteria established inpreconstruction tests a
47、re being met.13.3 Flexural bond strength determined by this test methodshall not be interpreted as the flexural bond strength of a wallconstructed of the same material, nor shall it be interpreted asan indication of extent of bond for purposes of water perme-ability evaluation. However, if effects o
48、f construction condi-tions, specimen size, workmanship, and curing conditions aretaken into account, the results may be used to estimate theflexural strength of a wall.14. Sampling14.1 Select representative samples of each lot of masonrymaterials intended for use in construction. Each sample ofmater
49、ial shall be of sufficient quantity to build a set of testprisms. A lot of each material shall consist of not less than thefollowing quantities:14.1.1 4000 of each type of masonry unit,14.1.2 15 bags of each type of cement (or the equivalentbulk quantity),14.1.3 15 bags of lime (or the equivalent bulk quantity),14.1.4 3 yd3of sand, and14.1.5 If mortar is delivered in bulk, 3 yd3of mortar.5Hedstrom, E. G., Tarhini, K. M., Thomas, R. D., Dubovoy, V. S., Klingner, R.E., and Cook, R. A., “Flexural Bond Strength of Concrete Masonry Prisms UsingPortland Cement and Hydrated Lime
