1、Designation: C780 11Standard 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 Department of Defense.INTRODUCTIONThis test meth
3、od 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 masonry
4、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 in t
5、he 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 mortars at
6、 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 or d
7、uring 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 Evalua
8、tionThis 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 assurance o
9、f 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 comp
10、ressive 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 standard.
11、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 and health practices and determine the applica-bility of regulatory limitations prior to use. For specific h
12、azardsstatements, see Section 8.2. Referenced Documents2.1 ASTM Standards:2C39/C39M Test Method for Compressive Strength of Cy-lindrical Concrete SpecimensC109/C109M Test Method for Compressive Strength ofHydraulic Cement Mortars (Using 2-in. or 50-mm CubeSpecimens)1This test method is under the jur
13、isdiction ofASTM 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 Aug. 1, 2011. Published August 2011. Originallyapproved in 1974. Last previous edition approved in 2010 as C780 10. DOI
14、:10.1520/C0780-112For 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.1*A Summary of Changes section appears at th
15、e end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.C128 Test Method for Density, Relative Density (SpecificGravity), and Absorption of Fine AggregateC173/C173M Test Method for Air Content of FreshlyMixed Concrete b
16、y the Volumetric MethodC187 Test Method for Amount of Water Required forNormal Consistency of Hydraulic Cement PasteC231 Test Method for Air Content of Freshly Mixed Con-crete by the Pressure MethodC270 Specification for Mortar for Unit MasonryC470/C470M Specification for Molds for Forming Con-crete
17、 Test Cylinders VerticallyC496/C496M Test Method for Splitting Tensile Strength ofCylindrical Concrete SpecimensC511 Specification for Mixing Rooms, Moist Cabinets,Moist Rooms, and Water Storage Tanks Used in theTesting of Hydraulic Cements and ConcretesC1093 Practice for Accreditation of Testing Ag
18、encies forMasonryC1586 Guide for Quality Assurance of MortarsE11 Specification for Woven Wire Test Sieve Cloth and TestSieves3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 Terms peculiar to testing masonry mortar are indicatedand defined below:3.1.2 disturbed sampleany plasti
19、c mortar test samplewhich is taken at some time after mixing and bulk sampling,that is further remixed or molded immediately prior to test, orboth.3.1.3 undisturbed sampleany plastic mortar test samplemolded immediately after mixing and sampling that sits on avibration-free surface until tested.3.2
20、During sampling, the following descriptions will iden-tify sample locations:3.2.1 Batch mixer samples are those obtained during orimmediately after the discharge of the mortar from the batchmixer.3.2.2 Mortar board samples are those obtained from themortar board after some established time period fr
21、om 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 mason, samples from a masonsmortar board shall be so identified to differentiate them fromsa
22、mples 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 mixed inthe laboratory using mechanical batch mixers. These trialbatches are sampled and used in
23、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 mortarperformance.4.2 During actual construction, evaluation of masonry mor-tars is possible
24、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 batch-to-batch variationsintroduced during mortar production and use at the construc-tion site
25、. 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 mortar compo-sition, and mortar plastic and hardened properties:4.3.1 Annex A1Consistency by Cone Penetration Test
26、Method,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 Annex A4Mortar Aggregate Ratio Test Method,4.3.5 Annex A5Mortar Air Content Test Method,4.3.6
27、 Annex A6Compressive Strength of Molded Ma-sonry Mortar Cylinders and Cubes, and4.3.7 Annex A7Splitting Tensile Strength of MoldedMasonry Mortar Cylinders.5. Significance and Use5.1 During preconstruction and construction evaluations,use of these test methods establishes specific and overallperforma
28、nce 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 Consistency deter
29、minations 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 tests, the cone
30、 preparation test serves to standardize wateradditions for mortars being considered as alternatives beforeconstruction. 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 Con
31、sistency retention by cone penetration (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 resul
32、ts reflect the relative performance of 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
33、the water content of the mortar mixture.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 perfor
34、med at the construction site.5.2.4 Mortar aggregate ratio testing (Annex A4) provides amethod for determining the ratio of aggregate-to-cementitiousC780 112materials. The sieving operation employed during this test isincapable of separating an individual cementitious materialwhen more than one such
35、material is used, but can accuratelyestablish 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-entrain
36、ing portland cement, air-entraining lime, masonrycement 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
37、 compressive strengthof mortar in the assembly 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
38、in the wall,primarily as a result of differences 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
39、 water loss, they havehigher water contents than 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 co
40、nfigurations yieldlower strengths than what would 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 mixturesare to be compared, the cylinder compressive strength is approximately85 %
41、 of the cube compressive strength.5.2.7 Splitting tensile strength (Annex A7) of molded mor-tar cylinders provides a method for determining the splittingtensile strength developing characteristics of the mortar. Themeasured strength is dependent upon the mortar water contentat the time of set, along
42、 with other factors, and reflects thegeneral strength attainable by the mortar in the masonry. Themeasured value, however, is not representative of the actualstrength of the mortar in the masonry.5.3 Testing during the actual construction may employ oneor more of the test methods described in 4.2. R
43、epetitive 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 may be referenced to laboratory testing and used to predictlater age mortar characteristics. I
44、n 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 batch-to-batch variations inmix ingredients and mixing time. Erratic consistency readingsindicate
45、 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 mixing procedure, for example,cement to aggregate, mortar water, or air content tests.5.3.2 Co
46、nsistency 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, weather conditions, effects ofchemical additives, and mixing time.5.3.3 Individual and repeated e
47、valuations 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) show the ability of the mixer operator toproperly and consistently add the cementitious mate
48、rial 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 stre
49、ngth tests (AnnexA6)of field batched mortars to preconstruction mortar compressiontests, each conducted in accordance with this test method, canbe used to identify variations in mortar mix constituents and/orproportions. Variations in compressive strength values typi-cally indicate changes in mix water content, mixing proce-dures, mix materials, material proportions, and environmentalconditions.NOTE 4Variations in the measured compressive strengths of field-sampled mortar and between the measured compressive strengths ofconstruction and pre-construction mortar sam
