1、Designation: C780 18Standard Test Method forPreconstruction and Construction Evaluation of Mortars forPlain and Reinforced Unit Masonry1This standard is issued under the fixed designation C780; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、 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.INTRODUCTIONThis test
3、 method provides a standard procedure for sampling and testing mortars for compositionand plastic and hardened properties, either before or during actual construction. The proceduresoutlined in the Annexes are considered applicable for evaluating various combinations of portlandcement, lime, and mas
4、onry cement for mortars common to plain and reinforced unit masonryconstruction.The test procedures describe methods for the measurement of mortar composition and mortarproperties. No attempt is made to claim or substantiate specific correlations between the measuredproperties and mortar performance
5、 in the masonry. However, data from these test methods can becombined with other information to formulate judgments about the quality of the masonry.Testing using these procedures is limited to the preconstruction evaluation of masonry mortarswithin the laboratory, to the evaluation of masonry morta
6、rs at the construction site, and in establishingthe degree of quality control exercised during mortar production at the construction site.1. Scope*1.1 This test method covers procedures for the sampling andtesting of mortars for composition and for their plastic andhardened properties, either before
7、 or during their actual use inconstruction.NOTE 1Guide C1586 provides guidance on evaluating mortar andclarifies the purpose of both this test method and Specification C270.NOTE 2The testing agency performing this test method should beevaluated in accordance with Practice C1093.1.2 Preconstruction E
8、valuationThis test method permitscomparisons of mortars made from different materials undersimulated field conditions. It is also used to establish baselinevalues for comparative evaluation of field mortars.1.3 Construction EvaluationUse of this method in thefield provides a means for quality assura
9、nce of field-mixedmortar. It includes methods for verifying the mortar mixproportions, comparing test results for field mortars to precon-struction testing, and determining batch-to-batch uniformity ofthe mortar.1.4 The test results obtained under this test method are notrequired to meet the minimum
10、 compressive values in accor-dance with the property specifications in Specification C270.1.5 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 stan
11、dard.1.6 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, health, and environmental practices and deter-mine the applicability of regulatory limitations prior t
12、o use.For specific hazards statements, see Section 8.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued
13、 by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.1This test method is under the jurisdiction of ASTM Committee C12 on Mortarsand Grouts for Unit Masonry and is the direct responsibility of SubcommitteeC12.02 on Research and Methods of Test.Current edition approved July 1,
14、2018. Published August 2018. Originallyapproved in 1974. Last previous edition approved in 2017 as C780 17. DOI:10.1520/C0780-18.*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
15、 StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers t
16、o Trade (TBT) Committee.12. Referenced Documents2.1 ASTM Standards:2C39/C39M Test Method for Compressive Strength of Cylin-drical Concrete SpecimensC109/C109M Test Method for Compressive Strength ofHydraulic Cement Mortars (Using 2-in. or 50-mm CubeSpecimens)C128 Test Method for Relative Density (Sp
17、ecific Gravity)and Absorption of Fine AggregateC173/C173M Test Method forAir Content of Freshly MixedConcrete by the Volumetric MethodC185 Test Method for Air Content of Hydraulic CementMortarC187 Test Method for Amount of Water Required for Nor-mal Consistency of Hydraulic Cement PasteC231 Test Met
18、hod for Air Content of Freshly Mixed Con-crete by the Pressure MethodC270 Specification for Mortar for Unit MasonryC470/C470M Specification for Molds for Forming ConcreteTest Cylinders VerticallyC511 Specification for Mixing Rooms, Moist Cabinets,Moist Rooms, and Water Storage Tanks Used in theTesti
19、ng of Hydraulic Cements and ConcretesC617 Practice for Capping Cylindrical Concrete SpecimensC1093 Practice for Accreditation of Testing Agencies forMasonryC1180 Terminology of Mortar and Grout for Unit MasonryC1231 Practice for Use of Unbonded Caps in Determinationof Compressive Strength of Hardene
20、d Cylindrical Con-crete SpecimensC1586 Guide for Quality Assurance of MortarsE11 Specification for Woven Wire Test Sieve Cloth and TestSieves3. Terminology3.1 Terminology defined in Terminology C1180 shall applyfor this test method.3.2 Definitions of Terms Specific to This Standard:3.2.1 Terms pecul
21、iar to testing masonry mortar are indicatedand defined below:3.2.2 disturbed sampleany plastic mortar test samplewhich is taken at some time after mixing and bulk sampling,that is further remixed or molded immediately prior to test, orboth.3.2.3 undisturbed sampleany plastic mortar test samplemolded
22、 immediately after mixing and sampling that sits on avibration-free surface until tested.3.3 During sampling, the following descriptions will iden-tify sample locations:3.3.1 Batch mixer samples are those obtained during orimmediately after the discharge of the mortar from the batchmixer.3.3.2 Morta
23、r board samples are those obtained from themortar board after some established time period from the endof mixing, and before retempering. Retempered mortar boardsamples are those obtained from the mortar board afterretempering. Since mortar on a masons mortar board isdisturbed by the activity of the
24、 mason, samples from a masonsmortar board shall be so identified to differentiate them fromsamples taken from a mortar board used exclusively for testpurposes.4. Summary of Test Method4.1 Preconstruction evaluation of mortar systems involvesthe preparation of one or more trial batches which are mixe
25、d inthe laboratory using mechanical batch mixers. These trialbatches are sampled and used in establishing the plastic andhardened properties of the mixtures. Because all the trialmixtures are prebatched by weight, additional characteristics ofthe mortars may be calculated and used in an analysis of
26、mortarperformance.4.2 During actual construction, evaluation of masonry mor-tars is possible by sampling the mortar at various stages ofconstruction, and performing tests on both its plastic andhardened properties. The test results permit further verificationof preconstruction testing, and reflect b
27、atch-to-batch variationsintroduced during mortar production and use at the construc-tion site. More immediate corrective action for the mixingprocedure is thereby attainable.4.3 The following test methods may be singly or collec-tively incorporated into the testing to establish mortarcomposition, an
28、d mortar plastic and hardened properties:4.3.1 Annex A1Consistency by Cone Penetration TestMethod,4.3.2 Annex A2Consistency Retention of Mortars forUnit Masonry,4.3.3 Annex A3Initial Consistency and Consistency Re-tention or Board Life of Masonry Mortars Using a ModifiedConcrete Pentrometer,4.3.4 An
29、nex A4Mortar Aggregate Ratio Test Method,4.3.5 Annex A5Mortar Air Content Test Method, and4.3.6 Annex A6Compressive Strength of Molded Ma-sonry Mortar Cylinders and Cubes.5. Significance and Use5.1 During preconstruction and construction evaluations,use of these test methods establishes specific and
30、 overallperformance characteristics for the mortar system.5.2 Preconstruction testing of mortars prebatched by weightprovides information for the selection of the individual mortarsystem best suited for the masonry to be constructed. Therecommended tests and their significance are as follows:5.2.1 C
31、onsistency determinations by cone penetration (An-nex A1) allow gaging the water additions for all mortarsincluded in the preconstruction test series. Even if the mortarconsistency as measured at the construction site is at a differentpenetration value than those measured during the preconstruc-tion
32、 tests, the cone preparation test serves to standardize wateradditions for mortars being considered as alternatives before2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, ref
33、er to the standards Document Summary page onthe ASTM website.C780 182construction. Additional testing of mortar water content-consistency relationships (Annex A4) will allow relating thesetwo factors to batch-to-batch variations at the construction site.5.2.2 Consistency retention by cone penetratio
34、n (AnnexA2)using disturbed or undisturbed mortar samples provides ameans of establishing the early-age setting and stiffeningcharacteristics of the mortars. Because laboratory testing isconducted under static climatic conditions, consistency reten-tion test results reflect the relative performance o
35、f the mortarsystems under test. The same general relationships are ex-pected to hold during testing at the construction project, exceptas they are influenced by jobsite weather conditions.5.2.3 Mortar water-content determinations (Annex A4) al-low measurement of the water content of the mortar mixtu
36、re.Mortars prebatched using moist masonry sand may be math-ematically analyzed for mortar water content; however, thistest, when used for preconstruction evaluation, establishes theeffectiveness of the test method and serves as the control orbase for tests performed at the construction site.5.2.4 Mo
37、rtar aggregate ratio testing (Annex A4) provides amethod for determining the ratio of aggregate-to-cementitiousmaterials. The sieving operation employed during this test isincapable of separating an individual cementitious materialwhen more than one such material is used, but can accuratelyestablish
38、 the aggregate-to-cementitious materials ratio of themixture.5.2.5 Mortar air-content testing (Annex A5) is useful inestablishing the value of this component of the mortar. This testis of particular importance in evaluating mortars that containair-entraining portland cement, air-entraining lime, mas
39、onrycement or any combination thereof.5.2.6 Compressive strength testing (Annex A6) of moldedmortar cylinders and cubes establishes one of the characteris-tics of hardened mortar. Mortar compressive strength testvalues are not representative of the actual compressive strengthof mortar in the assembl
40、y and are not appropriate for use inpredicting the compressive strength that would be attained bythe mortar in the masonry assembly. The measured compres-sive strength of a molded mortar specimen is almost alwayslower than the strength of the same mortar in the wall,primarily as a result of differen
41、ces in mortar water content andspecimen shape. Mortar compressive strength is influenced bymortar water content at the time of set. Because molded mortarspecimens are not in contact with absorptive masonry units andare not subjected to other mechanisms of water loss, they havehigher water contents t
42、han mortar in the wall. Higher watercontents almost always result in lower strengths. Specimen sizeand shape also affect compressive strength. Cylinders andcubes exhibit different strengths even when made from thesame mortar mix. Both of these specimen configurations yieldlower strengths than what w
43、ould be attained if a specimenhaving the same size and configuration of a typical mortar jointcould be reliably tested.NOTE 3When cube and cylinder test specimens from like mixtures areto be compared, the cylinder compressive strength is approximately 85 %of the cube compressive strength.5.3 Testing
44、 during the actual construction may employ oneor more of the test methods described in 4.2. Repetitive testingusing these test methods on consecutive or intermittent batchesprovides a method for measurement of batch-to-batch varia-tions in the mortar production. Testing during actual construc-tion m
45、ay be referenced to laboratory testing and used to predictlater age mortar characteristics. In addition to the comments in5.2, the following test meanings may be obtained fromconstruction project testing:5.3.1 Consistency by cone penetration (Annex A1) is usedas a quick reference for indicating batc
46、h-to-batch variations inmix ingredients and mixing time. Erratic consistency readingsindicate poor control during batching and mixing, but they donot indicate if cement, sand, or water additions are improper.Other test methods must be used to isolate and identify theunsatisfactory proportioning or m
47、ixing procedure, for example,cement to aggregate, mortar water, or air content tests.5.3.2 Consistency retention by cone penetration (AnnexA2)tests establishes the early-age setting and stiffening character-istics of the mortar. These properties are influenced by mixproportions and ingredients, weat
48、her conditions, effects ofchemical additives, and mixing time.5.3.3 Individual and repeated evaluations of mortar watercontent (Annex A4) show the ability of the mixer operator toproperly and consistently add water to the mixer.5.3.4 Individual and repeated tests for mortar aggregateratio (Annex A4)
49、 show the ability of the mixer operator toproperly and consistently add the cementitious material andsand to the mixer, and will establish batch-to-batch variationsin the composition of the mortar.5.3.5 Individual and repetitive tests for mortar air content(Annex A5) show the changes caused by variations in mixingtime, mixing efficiency and other factors.5.3.6 Comparison of compressive strength tests (Annex A6)of field batched mortars to preconstruction mortar compressiontests, each conducted in accordance with this test method, canbe used to identify variations in
