1、Designation: C 780 07Standard Test Method forPreconstruction and Construction Evaluation of Mortars forPlain and Reinforced Unit Masonry1This standard is issued under the fixed designation C 780; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 m
3、ethod 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 mason
4、ry 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 i
5、n 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 mortars
6、 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 o
7、r during their actual use inconstruction.NOTE 1Guide C 1586 provides guidance on evaluating mortar andclarifies the purpose of both this test method and Specification C 270.NOTE 2The testing agency performing this test method should beevaluated in accordance with Practice C 1093.1.2 Preconstruction
8、EvaluationThis 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 assur
9、ance 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 minimu
10、m compressive values in accor-dance with the property specifications in Specification C 270.1.5 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 pract
11、ices and determine the applica-bility of regulatory limitations prior to use. For specific hazardsstatements, see Section 8.2. Referenced Documents2.1 ASTM Standards:2C 39/C 39M Test Method for Compressive Strength of Cy-lindrical Concrete SpecimensC 109/C 109M Test Method for Compressive Strength o
12、fHydraulic Cement Mortars(Using 2-in. or 50-mm CubeSpecimens)C 128 Test Method for Density, Relative Density (SpecificGravity), and Absorption of Fine AggregateC 173/C 173M Test Method for Air Content of Freshly1This test method is under the jurisdiction ofASTM Committee C12 on Mortarsand Grouts for
13、 Unit Masonry and is the direct responsibility of SubcommitteeC12.02 on Research and Methods of Test.Current edition approved July 15, 2007. Published August 2007. Originallyapproved in 1974. Last previous edition approved in 2006 as C 780 06a.2For referenced ASTM standards, visit the ASTM website,
14、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 the end of this standard.Copyright ASTM International, 100 Barr Harbor Driv
15、e, PO Box C700, West Conshohocken, PA 19428-2959, United States.Mixed Concrete by the Volumetric MethodC 187 Test Method for Normal Consistency of HydraulicCementC 231 Test Method for Air Content of Freshly MixedConcrete by the Pressure MethodC 270 Specification for Mortar for Unit MasonryC 470/C 47
16、0M Specification for Molds for Forming Con-crete Test Cylinders VerticallyC 496/C 496M Test Method for Splitting Tensile Strengthof Cylindrical Concrete SpecimensC511 Specification for Mixing Rooms, Moist Cabinets,Moist Rooms, and Water Storage Tanks Used in theTesting of Hydraulic Cements and Concr
17、etesC 1093 Practice for Accreditation of Testing Agencies forMasonryC 1586 Guide for Quality Assurance of MortarsE11 Specification for Wire Cloth and Sieves for TestingPurposes3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 Terms peculiar to testing masonry mortar are indicate
18、dand defined below:3.1.2 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.3.1.3 undisturbed sampleany plastic mortar test samplemolded immediately after mixing and sampling tha
19、t sits on avibration-free surface until tested.3.2 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 th
20、emortar 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 mason, samples from a masonsmortar board
21、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 mixed inthe laboratory using mechanical batch
22、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 mortarperformance.4.2 During actual constr
23、uction, 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 batch-to-batch variationsintroduced during
24、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 mortar compo-sition, and mortar plastic and hardened properties
25、: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 Annex A4Mortar Aggregate Ratio Test Method
26、,4.3.5 Annex A5Mortar Air Content Test Method,4.3.6 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 te
27、st methods establishes specific and 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
28、significance are as follows:5.2.1 Consistency determinations by cone penetration allowgaging the water additions for all mortars included in thepreconstruction test series. Even if the mortar consistency asmeasured at the construction site is at a different penetrationvalue than those measured durin
29、g the preconstruction tests, thecone preparation test serves to standardize water additions formortars being considered as alternatives before construction.Additional testing of mortar water content-consistency rela-tionships (Annex A4) will allow relating these two factors tobatch-to-batch variatio
30、ns at the construction site.5.2.2 Consistency retention by cone penetration using dis-turbed or undisturbed mortar samples provides a means ofestablishing the early-age setting and stiffening characteristicsof the mortars. Because laboratory testing is conducted understatic climatic conditions, cons
31、istency retention test resultsreflect the relative performance of the mortar systems undertest. The same general relationships are expected to holdduring testing at the construction project, except as they areinfluenced by jobsite weather conditions.5.2.3 Mortar water-content determinations (Annex A
32、4) al-low measurement of 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 contro
33、l orbase for tests performed at the construction site.5.2.4 Mortar aggregate ratio testing provides a method fordetermining the ratio of aggregate-to-cementitious materials.The sieving operation employed during this test is incapable ofseparating an individual cementitious material when more thanC78
34、0072one such material is used, but can accurately establish theaggregate-to-cementitious materials ratio of the mixture.5.2.5 Mortar air-content testing is useful in establishing thevalue of this component of the mortar. This test is of particularimportance in evaluating mortars that contain air-ent
35、rainingportland cement, air-entraining lime, masonry cement or anycombination thereof.5.2.6 Compressive strength testing of molded mortar cylin-ders and cubes allows establishment of the strength developingcharacteristics of the mortar. The measured strength is depen-dent upon the mortar water conte
36、nt at the time of set, alongwith other factors, and reflects the general strength that wouldbe attained by the mortar in the masonry. The measured valueshall not, however, be construed as being representative of theactual strength of the mortar in the masonry. Due to specimenshapescylinders versus c
37、ubesthe strength results betweenthe two different-shaped specimens of identical mortar willvary.NOTE 3When cube and cylinder test specimens from like mixturesare to be compared, the cylinder compressive strength may be consideredto be equal to 85 % of the cube compressive strength.5.2.7 Splitting te
38、nsile strength of molded mortar cylindersprovides a method for determining the splitting tensile strengthdeveloping characteristics of the mortar. The measuredstrength is dependent upon the mortar water content at the timeof set, along with other factors, and reflects the general strengthattainable
39、by the mortar in the masonry. The measured value,however, is not representative of the actual strength of themortar in the masonry.5.3 Testing during the actual construction may employ oneor more of the test methods described in 4.2. Repetitive testingusing these test methods on consecutive or inter
40、mittent 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. In addition to the comments in5.2, the following test meanings may
41、 be obtained fromconstruction project testing:5.3.1 Consistency by cone penetration is used as a quickreference for indicating batch-to-batch variations in mix ingre-dients and mixing time. Erratic consistency readings indicatepoor control during batching and mixing, but they do notindicate if cemen
42、t, sand, or water additions are improper. Othertest methods must be used to isolate and identify the unsatis-factory proportioning or mixing procedure, for example, ce-ment to aggregate, mortar water, or air content tests.5.3.2 Consistency retention by cone penetration tests estab-lishes the early-a
43、ge setting and stiffening characteristics of themortar. These properties are influenced by mix proportions andingredients, weather conditions, effects of chemical additives,and mixing time.5.3.3 Individual and repeated evaluations of mortar watercontent (Annex A4) show the ability of the mixer opera
44、tor toproperly and consistently add water to the mixer.5.3.4 Individual and repeated tests for mortar aggregateratio show the ability of the mixer operator to properly andconsistently add the cementitious material and sand to themixer, and will establish batch-to-batch variations in thecomposition o
45、f the mortar.5.3.5 Individual and repetitive tests for mortar air contentshow the changes caused by variations in mixing time, mixingefficiency and other factors.5.3.6 Compressive strength tests of molded cylinders andcubes stored in accordance with the test method reflectapproximate mortar strength
46、s because lower water-cementratio mortars are found in the wall than are typically measuredfor mortars from the mixer.5.3.7 Splitting tensile strengths of molded cylinders storedin accordance with the test method reflect the approximatestrength of the masonry mortar because lower water-cementratio m
47、ortars are found in the wall than are typically measuredfor mortars from the mixer.6. Test Method Limitations6.1 During mortar aggregate ratio testing, no attempt hasbeen made to establish the proportions of either portlandcement to lime or portland cement to masonry cement in themixture. Additional
48、 testing could establish this proportioning,however, batching operations should be supervised to ensurethe correct proportioning of these ingredients.6.2 Due to the greater ability to weigh materials accurately,mix on a precise schedule, and control other factors relating tothe production and testin
49、g of mortar under laboratory condi-tions as compared to field conditions, the principal purpose ofthis test method is to provide a means to identify, measure,evaluate, and control differences that exist between laboratoryand jobsite mortars.6.3 There is no ASTM standard method for measuring thecomposition or physical properties of hardened mortars re-moved from a structure.7. Apparatus7.1 The apparatus required for this test, along with theapparatus for sampling (see Section 9) are given in theindividual tests included in the annexes.8. Hazards8.1 During any period
copyright@ 2008-2019 麦多课文库（www.mydoc123.com）网站版权所有
备案/许可证编号：苏ICP备17064731号-1