1、Designation: C 1072 06Standard Test Method forMeasurement of Masonry Flexural Bond Strength1This standard is issued under the fixed designation C 1072; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A nu
2、mber 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.1. Scope*1.1 This test method covers the determination of flexuralb
3、ond strength of nonreinforced masonry by physical testing ofeach joint of masonry prisms.1.2 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 practice
4、s and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C67 Test Methods of Sampling and Testing Brick andStructural Clay TileC 140 Test Methods of Sampling and Testing ConcreteMasonry UnitsC 270 Specification for Mortar for Unit MasonryC
5、780 Test Method for Preconstruction and ConstructionEvaluation of Mortars for Plain and Reinforced UnitMasonryC 1357 Test Methods for Evaluating Masonry BondStrengthC 1532 Practice for Selection, Removal, and Shipment ofMasonry Assemblage Specimens from Existing Construc-tion3. Significance and Use3
6、.1 This test method is intended to provide a simple andeconomical means for the determination of comparative valuesof flexural bond strength. It may be used either on specimensespecially fabricated for bond strength evaluation or on speci-mens cut from existing masonry.3.2 The bond strengths determi
7、ned from this test methodcan be used as a means of evaluating the compatibility ofmortars and masonry units. It may also be used to determinethe effect on flexural bond strength of such factors as masonryunit and mortar properties, workmanship, curing conditions,coatings on masonry units, or any oth
8、er factors that may be ofconcern.3.3 Flexural bond strength determined by this test methodshould not be interpreted as the flexural bond strength of a wallconstructed of the same material. However, results may beused to predict the flexural strength of a wall. Nor should it beinterpreted as an indic
9、ation of extent of bond for purposes ofwater permeance evaluation.4. Apparatus4.1 The test apparatus is shown in Figs. 1-4. The upper andlower clamping mechanisms shall be constructed as shown,except that the hex head bolts are permitted to be replaced byother tightening devices of equal, or greater
10、, strength andstiffness. The support frame shall be constructed as shown orshall be constructed using configurations and materials ofequal, or greater, strength and stiffness. The testing apparatusshall be constructed to apply the load vertically downward onthe upper clamping system in such a manner
11、 that the upper andlower clamp do not come in contact during the tests. The prismsupport system shall be able to accommodate the size of theprism to be tested.5. Sampling and Testing5.1 Brick Masonry UnitsRepresentative brick masonryunits shall be sampled and tested in accordance with TestMethods C6
12、7.NOTE 1Brick properties for which there are methods of test in TestMethods C67that may be of interest are cold-water absorption, boiling-water absorption, initial rate of absorption, and compressive strength.1This test method is under the jurisdiction of ASTM Committee C15 onManufactured Masonry Un
13、its and is the direct responsibility of SubcommitteeC15.04 on Research.Current edition approved June 1, 2006. Published June 2006. Originallyapproved in 1993. Last previous edition approved in 2005 as C 107205b.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Cust
14、omer 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 Drive, PO Box C700, West Conshohocken
15、, PA 19428-2959, United States.5.2 Concrete Masonry UnitsRepresentative concrete ma-sonry units shall be sampled and tested in accordance with TestMethods C 140.5.3 MortarWhen mortar property testing is specified, thecompressive strength, air content, initial flow, cone penetration,and water retenti
16、on shall be determined in accordance with therequirements of Specification C 270 or Test Method C 780.6. Test Specimen6.1 The test specimen shall consist of one or more prism(s).Each prism shall have not more than five joints and a minimumwidth (b) of 3.5 in. (see Note 2) as shown in Fig. X1.1.NOTE
17、2It is recommended that a width (b) of 1 full masonry unit beused. However, full widths may not be possible for samples obtained inaccordance with 6.3.2.6.2 Test a minimum of fifteen joints for prisms fabricated inthe laboratory or field, and five joints for prisms removed fromexisting masonry.6.3 C
18、onstruct prisms in a laboratory or in the field orremove from existing masonry. Keep handling of the prisms toa minimum and handle in such a way that the joints will not besubjected to detrimental tensile stresses.6.3.1 Prisms Fabricated in Laboratory or Field:6.3.1.1 Set the first unit of each pris
19、m on a firm, horizontalsurface without the use of mortar.NOTE 3An alignment device may be used to ensure plumbness andjoint thickness uniformity.6.3.1.2 Place a full or face shell mortar bed on all unitswithout furrowing unless the effect of furrowing is beingstudied.6.3.1.3 Immediately place the ne
20、xt course on the mortar bedand tap it to proper level and joint thickness. One face of eachprism shall be in a nearly true plane.6.3.1.4 Repeat 6.3.1.2 and 6.3.1.3 until the prisms are thedesired height. Identify all specimens using a water-resistantmarker.6.3.1.5 Depending upon the desired test con
21、ditions, strikeflush or tool the mortar joints. If tooling is required, tool onlythe joints on one face of each prism.6.3.1.6 Unless specified otherwise, enclose all prisms in amoisture-tight bag and cure for 28 days. Record and report thedaily high and low temperatures in the area where specimensar
22、e stored for curing. For prisms cured in laboratory air,maintain the laboratory air at 75 6 15 F (24 6 8 C). If othercuring conditions (e.g. no moisture-tight bag) are specified,record and report all details of the curing.NOTE 4Workmanship during fabrication, temperature of the materialsduring fabri
23、cation, curing conditions, time between removal from moistcuring to test, and other factors may affect the bond strengths measured bythis test. Standardized specimen fabrication and curing procedures thatattempt to control these variables are prescribed in Test Methods C 1357.6.3.1.7 When prisms are
24、 made during construction at the jobsite, they shall be constructed in a location where they will notbe disturbed, but will be subjected to atmospheric conditionssimilar to those in the masonry structure whose properties theyare intended to represent.6.3.2 Prisms Obtained from Existing Masonry:6.3.2
25、.1 Remove, document and transport prisms from exist-ing masonry in accordance with Practice C 1532.6.3.2.2 Where mortar fins and extrusions project from thespecimen to the extent that they may interfere with theFIG. 1 Bond Wrench Testing ApparatusC1072062attachment of the bond wrench, they shall be
26、removed withoutcausing damage to the specimen. Remove only enough mate-rial to enable proper attachment of the bond wrench.7. Procedure7.1 Place the prism vertically in the support frame as shownin Fig. 1, and clamp firmly into a locked position using thelower clamping bracket. Orient the prism so t
27、hat the face of thejoint intended to be subjected to flexural tension is on the sameside of the specimen as the clamping screws. The prism shallbe positioned at the required elevation that results in a singlebrick projecting above the lower clamping bracket.7.2 Attach the upper clamping bracket to t
28、he top brick asshown in Fig. 1. Tighten each clamping bolt using a torque notgreater than 50 lbfin. (5.7 Nm).7.3 Lower base support away from the bottom of the brickprism so that no contact occurs during testing.7.4 Apply the load at a uniform rate so that the total load isapplied in not less than 1
29、 min or more than 3 min. Measureload (see Note 5) to an accuracy of 62 % with maximum errorof 5 lbf (22 N).NOTE 5The load indicated in Fig. 1 may be applied by any means,such as a testing machine, hydraulic jack, dead weights, etc. but must bewithin 63 of vertical. Load may be measured using the tes
30、ting machineindicator, proving ring, load cell, or any device capable of the prescribedprecision. Special attention must be given to non-recording load measur-ing devices. Since failure of the specimen is sudden, the device must becontinuously monitored or the failure load will be lost.FIG. 2 Bond W
31、rench Frame and ElevationC1072063FIG. 3 Material List and Detail DrawingsC1072064FIG. 4 Detail Drawings of Bond WrenchC1072065FIG. 4 Detail Drawings of Bond Wrench (continued)C1072066FIG. 4 Detail Drawings of Bond Wrench (continued)C10720678. Calculations8.1 For specimens built of solid masonry unit
32、s (at least 75 %net area), calculate the gross area flexural strength as follows:Fg56PL 1 PlLl!bd22P 1 Pl!bd(1)where:Fg= gross area flexural tensile strength, psi (MPa),P = maximum applied load, lbf (N),Pl= weight of loading arm, lbf (N), (see Appendix X1),L = distance from center of prism to loadin
33、g point, in.(mm),Ll= distance from center of prism to centroid of loadingarm, in. (mm) (see Appendix X1),b = cross-sectional width of the mortar-bedded area, mea-sured perpendicular to the loading arm of the upperclamping bracket as determined in 8.3 (see Fig. 5),andd = cross-sectional depth of the
34、mortar-bedded area, mea-sured parallel to the loading arm of the upper clamp-ing bracket as determined in 8.4 (see Fig. 5).8.2 For prisms built with hollow masonry units (less than75 % net area), calculate the net area flexural tensile stress asfollows:Fn5PL 1 PlLlSP 1 PlAn(2)where:Fn= net area flex
35、ural tensile strength, psi (MPa),S = section modulus of the net bedded area of the prism,in.3(mm3), andAn= net bedded area of the prism, in.2(mm2).8.2.1 If hollow masonry prisms are constructed using faceshell mortar bedding in which opposing face shells are equal inthickness (within18 in. (3 mm) an
36、d are symmetrical about thecentroidal axis of the prism, calculate the section properties ofthe prism as follows:An5 2b tfs! (3)S 5 I/cc 5 d/2I 5 2Fb 3 tfs!3121 b 3 tfs! 3 Sc tfs2D2G 5btfs!361btfs3 d2tfs!22An= net bedded area of the prism, in.2(mm2),S = section modulus of the net bedded area of the
37、prism,in.3(mm3),I = moment of inertia of the net bedded area of the prism,in.4(mm4),c = distance from the centroid to the most extremetension fiber of the mortar bedded area, in. (mm),b = cross-sectional width of the mortar-bedded area, mea-sured perpendicular to the loading arm of the upperclamping
38、 bracket as determined in 8.3 (see Fig. 6),d = cross-sectional depth of the mortar-bedded area, mea-sured parallel to the loading arm of the upper clamp-ing bracket as determined in 8.4 (see Fig. 6), andtfs= minimum face shell thickness of unit (determined inaccordance with Test Methods C 140), in.
39、(mm) (seeFig. 6).8.3 Determine the cross-sectional width of the mortar-bedded area, measured perpendicular to the loading arm of theupper clamping bracket, b, as follows:8.3.1 For clay masonry units, determine the length of theunit using Test Methods C67. This length shall be consideredas the cross-
40、sectional width of the mortar-bedded area, b,asdefined in this test method.8.3.2 For concrete masonry units, determine the length ofthe unit using Test Methods C 140. This length (referred to asL in Test Methods C 140) shall be considered as the cross-sectional width of the mortar-bedded area, b, as
41、 defined in thistest method.8.4 Determine the cross-sectional depth of the mortar-bedded area, measured parallel to the loading arm of the upperclamping bracket, d, as follows:8.4.1 For clay masonry units, determine the width of theunit using Test Methods C67. This width shall be consideredas the cr
42、oss-sectional depth of the mortar-bedded area, d,asdefined in this test method.8.4.2 For concrete masonry units, determine the width of theunit using Test Methods C 140. This width (referred to as W inTest Methods C 140) shall be considered as the cross-sectionaldepth of the mortar-bedded area, d, a
43、s defined in this testmethod.9. Report9.1 Report the following information:9.1.1 Identification number of prism,9.1.2 Average prism dimensions to the nearest 0.05 in. (1.0mm) including width, depth, and height,FIG. 5 Example Cross-Section of Solid Masonry UnitsC10720689.1.3 Weight of specimen, lbf (
44、N),9.1.4 Individual and average gross or net area flexuraltensile stress calculated to the nearest psi (MPa), standarddeviation, and position of the joint tested within the specimen.If a mortar joint breaks during the handling of the specimenand tightening of the loading clamps but before additional
45、 loadis applied by the testing apparatus, report which joint(s) brokeprematurely but do not include them in the calculation of theflexural tensile strength average and standard deviation. Thetop mortar joint shall be designated joint Number 1, the second,Number 2, etc. Measured loads and calculation
46、 shall also beincluded,9.1.5 Description of failure, especially indicating whetherfailure occurred at the top or bottom of the mortar joint, orboth,9.1.6 Sketch or photo of masonry unit showing core con-figuration and mortar bedded area, full or face shell, and9.1.7 Description of bonding pattern, j
47、oint tooling, locationof tooled joint during test, and joint thickness.9.2 Where specified the report shall include the following:9.2.1 Type and mix proportions of mortar,9.2.2 Compressive strength of mortar, psi (MPa),9.2.3 Initial flow or cone penetration of mortar as used,9.2.4 Water retention of
48、 mortar,9.2.5 Mortar air content,9.2.6 Physical properties of masonry units, and9.2.7 Curing history and age of specimen at each break.10. Precision and Bias10.1 Insufficient data is currently available for a precisionand bias statement.11. Keywords11.1 assemblies; bond; flexural; masonry; tensileFI
49、G. 6 Example Dimensions of Hollow Masonry Units Used toDetermine Section PropertiesC1072069APPENDIX(Nonmandatory Information)X1. DETERMINATION OF WEIGHT AND CENTROID OF UPPER CLAMPING BRACKETX1.1 Side and plan views of the upper clamping bracket areillustrated in Fig. X1.1. The weight (P) of the upper clampingbracket including the loading arm, is determined by weighingto the nearest 25 g or oz. A brick weighing within 0.1 lbf (0.44N) and having a thickness (d) within 0.25 in. (6 mm) of thosebeing tested must be clamped into the position shown for thebrick
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