1、Designation: C780 18C780 18aStandard 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
2、 case of 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.INTRODUCTIONT
3、his test 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,
4、 and masonry 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 per
5、formance 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 mason
6、ry mortars 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 and testing of mortars for composition and for their plastic andhardened properties, eith
7、er before or during their actual use in construction.NOTE 1Guide C1586 provides guidance on evaluating mortar and clarifies the purpose of both this test method and Specification C270.NOTE 2The testing agency performing this test method should be evaluated in accordance with Practice C1093.1.2 Preco
8、nstruction EvaluationThis test method permits comparisons of mortars made from different materials undersimulated field conditions. It is also used to establish baseline values for comparative evaluation of field mortars.1.3 Construction EvaluationUse of this method in the field provides a means for
9、 quality assurance of field-mixed mortar. Itincludes methods for verifying the mortar mix proportions, comparing test results for field mortars to preconstruction testing, anddetermining batch-to-batch uniformity of the mortar.1.4 The test results obtained under this test method are not required to
10、meet the minimum compressive values in accordancewith the property specifications in Specification C270.1.5 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information only and are not
11、 considered standard.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability ofregulatory limit
12、ations prior to use. For specific hazards statements, see Section 8.1.7 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommenda
13、tions issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.1 This test method is under the jurisdiction of ASTM Committee C12 on Mortars and Grouts for Unit Masonry and is the direct responsibility of Subcommittee C12.02on Research and Methods of Test.Current edition app
14、roved July 1, 2018Aug. 15, 2018. Published August 2018September 2018. Originally approved in 1974. Last previous edition approved in 20172018as C780 17.C780 18. DOI: 10.1520/C0780-18.10.1520/C0780-18A.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard
15、an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is
16、to be considered the official document.*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 States12. Referenced Documents2.1 ASTM Standards:2C39/C39M Test Method for Compressive St
17、rength of Cylindrical Concrete SpecimensC109/C109M Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 2-in. or 50-mm Cube Specimens)C128 Test Method for Relative Density (Specific Gravity) and Absorption of Fine AggregateC173/C173M Test Method for Air Content of Freshly Mixed Co
18、ncrete by the Volumetric MethodC185 Test Method for Air Content of Hydraulic Cement MortarC187 Test Method for Amount of Water Required for Normal Consistency of Hydraulic Cement PasteC231 Test Method for Air Content of Freshly Mixed Concrete by the Pressure MethodC270 Specification for Mortar for U
19、nit MasonryC470/C470M Specification for Molds for Forming Concrete Test Cylinders VerticallyC511 Specification for Mixing Rooms, Moist Cabinets, Moist Rooms, and Water Storage Tanks Used in the Testing of HydraulicCements and ConcretesC617 Practice for Capping Cylindrical Concrete SpecimensC1093 Pra
20、ctice for Accreditation of Testing Agencies for MasonryC1180 Terminology of Mortar and Grout for Unit MasonryC1231 Practice for Use of Unbonded Caps in Determination of Compressive Strength of Hardened Cylindrical ConcreteSpecimensC1586 Guide for Quality Assurance of MortarsE11 Specification for Wov
21、en Wire Test Sieve Cloth and Test Sieves3. Terminology3.1 Terminology defined in Terminology C1180 shall apply for this test method.3.2 Definitions of Terms Specific to This Standard:3.2.1 Terms peculiar to testing masonry mortar are indicated and defined below:3.2.2 disturbed sampleany plastic mort
22、ar test sample which is taken at some time after mixing and bulk sampling, that isfurther remixed or molded immediately prior to test, or both.3.2.3 undisturbed sampleany plastic mortar test sample molded immediately after mixing and sampling that sits on avibration-free surface until tested.3.3 Dur
23、ing sampling, the following descriptions will identify sample locations:3.3.1 Batch mixer samples are those obtained during or immediately after the discharge of the mortar from the batch mixer.3.3.2 Mortar board samples are those obtained from the mortar board after some established time period fro
24、m the end ofmixing, and before retempering. Retempered mortar board samples are those obtained from the mortar board after retempering.Since mortar on a masons mortar board is disturbed by the activity of the mason, samples from a masons mortar board shall beso identified to differentiate them from
25、samples taken from a mortar board used exclusively for test purposes.4. Summary of Test Method4.1 Preconstruction evaluation of mortar systems involves the preparation of one or more trial batches which are mixed in thelaboratory using mechanical batch mixers. These trial batches are sampled and use
26、d in establishing the plastic and hardenedproperties of the mixtures. Because all the trial mixtures are prebatched by weight, additional characteristics of the mortars maybe calculated and used in an analysis of mortar performance.4.2 During actual construction, evaluation of masonry mortars is pos
27、sible by sampling the mortar at various stages ofconstruction, and performing tests on both its plastic and hardened properties. The test results permit further verification ofpreconstruction testing, and reflect batch-to-batch variations introduced during mortar production and use at the constructi
28、on site.More immediate corrective action for the mixing procedure is thereby attainable.4.3 The following test methods may be singly or collectively incorporated into the testing to establish mortar composition, andmortar plastic and hardened properties:4.3.1 Annex A1Consistency by Cone Penetration
29、Test Method,4.3.2 Annex A2Consistency Retention of Mortars for Unit Masonry,4.3.3 AnnexA3Initial Consistency and Consistency Retention or Board Life of Masonry Mortars Using a Modified ConcretePentrometer,4.3.4 Annex A4Mortar Aggregate Ratio Test Method,4.3.5 Annex A5Mortar Air Content Test Method,
30、and2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.C780 18a24.3.6 Annex A6Compressive Strength of Molded Maso
31、nry Mortar Cylinders and Cubes.5. Significance and Use5.1 During preconstruction and construction evaluations, use of these test methods establishes specific and overall performancecharacteristics for the mortar system.5.2 Preconstruction testing of mortars prebatched by weight provides information
32、for the selection of the individual mortarsystem best suited for the masonry to be constructed. The recommended tests and their significance are as follows:5.2.1 Consistency determinations by cone penetration (Annex A1) allow gaging the water additions for all mortars included inthe preconstruction
33、test series. Even if the mortar consistency as measured at the construction site is at a different penetration valuethan those measured during the preconstruction tests, the cone preparation test serves to standardize water additions for mortarsbeing considered as alternatives before construction. A
34、dditional testing of mortar water content-consistency relationships (AnnexA4) will allow relating these two factors to batch-to-batch variations at the construction site.5.2.2 Consistency retention by cone penetration (Annex A2) using disturbed or undisturbed mortar samples provides a meansof establ
35、ishing the early-age setting and stiffening characteristics of the mortars. Because laboratory testing is conducted understatic climatic conditions, consistency retention test results reflect the relative performance of the mortar systems under test. Thesame general relationships are expected to hol
36、d during testing at the construction project, except as they are influenced by jobsiteweather conditions.5.2.3 Mortar water-content determinations (Annex A4) allow measurement of the water content of the mortar mixture. Mortarsprebatched using moist masonry sand may be mathematically analyzed for mo
37、rtar water content; however, this test, when used forpreconstruction evaluation, establishes the effectiveness of the test method and serves as the control or base for tests performedat the construction site.5.2.4 Mortar aggregate ratio testing (Annex A4) provides a method for determining the ratio
38、of aggregate-to-cementitiousmaterials. The sieving operation employed during this test is incapable of separating an individual cementitious material whenmore than one such material is used, but can accurately establish the aggregate-to-cementitious materials ratio of the mixture.5.2.5 Mortar air-co
39、ntent testing (Annex A5) is useful in establishing the value of this component of the mortar. This test is ofparticular importance in evaluating mortars that contain air-entraining portland cement, air-entraining lime, masonry cement or anycombination thereof.5.2.6 Compressive strength testing (Anne
40、x A6) of molded mortar cylinders and cubes establishes one of the characteristics ofhardened mortar. Mortar compressive strength test values are not representative of the actual compressive strength of mortar in theassembly and are not appropriate for use in predicting the compressive strength that
41、would be attained by the mortar in the masonryassembly. The measured compressive strength of a molded mortar specimen is almost always lower than the strength of the samemortar in the wall, primarily as a result of differences in mortar water content and specimen shape. Mortar compressive strengthis
42、 influenced by mortar water content at the time of set. Because molded mortar specimens are not in contact with absorptivemasonry units and are not subjected to other mechanisms of water loss, they have higher water contents than mortar in the wall.Higher water contents almost always result in lower
43、 strengths. Specimen size and shape also affect compressive strength. Cylindersand cubes exhibit different strengths even when made from the same mortar mix. Both of these specimen configurations yield lowerstrengths than what would be attained if a specimen having the same size and configuration of
44、 a typical mortar joint could bereliably tested.NOTE 3When cube and cylinder test specimens from like mixtures are to be compared, the cylinder compressive strength is approximately 85 % ofthe cube compressive strength.5.3 Testing during the actual construction may employ one or more of the test met
45、hods described in 4.2. Repetitive testing usingthese test methods on consecutive or intermittent batches provides a method for measurement of batch-to-batch variations in themortar production. Testing during actual construction may be referenced to laboratory testing and used to predict later age mo
46、rtarcharacteristics. In addition to the comments in 5.2, the following test meanings may be obtained from construction project testing:5.3.1 Consistency by cone penetration (Annex A1) is used as a quick reference for indicating batch-to-batch variations in mixingredients and mixing time. Erratic con
47、sistency readings indicate poor control during batching and mixing, but they do notindicate if cement, sand, or water additions are improper. Other test methods must be used to isolate and identify the unsatisfactoryproportioning or mixing procedure, for example, cement to aggregate, mortar water, o
48、r air content tests.5.3.2 Consistency retention by cone penetration (Annex A2) tests establishes the early-age setting and stiffening characteristicsof the mortar.These properties are influenced by mix proportions and ingredients, weather conditions, effects of chemical additives,and mixing time.5.3
49、.3 Individual and repeated evaluations of mortar water content (AnnexA4) show the ability of the mixer operator to properlyand consistently add water to the mixer.5.3.4 Individual and repeated tests for mortar aggregate ratio (AnnexA4) show the ability of the mixer operator to properly andconsistently add the cementitious material and sand to the mixer, and will establish batch-to-batch variations in the compositionof the mortar.5.3.5 Individual and repetitive tests for mortar air content (Annex A5) show the changes caused by variations in mixing time,mixing eff
