ASTM E518/E518M-22

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Designation: E518/E518M − 21 E518/E518M − 22
Standard Test Methods for
Flexural Bond Strength of Masonry
This standard is issued under the fixed designation E518/E518M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 These test methods cover determination of the flexural bond strength of unreinforced masonry assemblages. Two procedures
are provided:
1.1.1 Test Method A—Simply supported beam with third-point loading.
1.1.2 Test Method B—Simply supported beam with uniform loading.
NOTE 1—Third-point loading (Test Method A) produces a moment distribution that is significantly different from uniformly distributed loading (Test
Method B).Third-point loading (Test Method A) subjects more mortar joints to the maximum moment and thus, is likely to produce more conservative
capacities than uniform loading (Test Method B).
1.2 The text of this standard refers to notes and footnotes that provide explanatory material. These notes and footnotes (excluding
those in tables and figures) shall not be considered as requirements of the standard.
1.3 These test methods cover the application of the tests using either inch-pound or SI units. The values stated in either SI units
or inch-pound units are to be regarded separately as standard. Within the text, the inch-pound units are shown in brackets. The
values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other.
Combining values from the two systems may result in nonconformance with the standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
C67C67/C67M Test Methods for Sampling and Testing Brick and Structural Clay Tile
C78C78/C78M Test Method for Flexural Strength of Concrete (Using Simple Beam with Third-Point Loading)
C140C140/C140M Test Methods for Sampling and Testing Concrete Masonry Units and Related Units
These test methods are under the jurisdiction of ASTM Committee C15 on Manufactured Masonry Units and are the direct responsibility of Subcommittee C15.04 on
Research.
Current edition approved June 1, 2021Dec. 1, 2022. Published January 2016December 2022. Originally approved in 1974. Last previous edition approved in 20152021
as E518 – 15.E518/E518M – 21. DOI: 10.1520/E0518_E0518M-21.10.1520/E0518_E0518M-22.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
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E518/E518M − 22
C270 Specification for Mortar for Unit Masonry
C778 Specification for Standard Sand
C1232 Terminology for Masonry
C1717 Test Methods for Conducting Strength Tests of Masonry Wall Panels
E4 Practices for Force Calibration and Verification of Testing Machines
E575 Practice for Reporting Data from Structural Tests of Building Constructions, Elements, Connections, and Assemblies
3. Terminology
3.1 For terms used in these test methods, refer to Terminology C1232.
4. Significance and Use
4.1 These test methods are intended to provide simplified and economical means for gathering comparative research data on the
flexural bond strength developed with different types of masonry units and mortar or for the purpose of checking job quality control
(materials and workmanship).
NOTE 2—These test methods are not intended for use in establishing design stresses. For this purpose, Test Methods C1717 should be used.
5. Apparatus
5.1 Testing Machine, conforming to the requirements of Practices E4.
5.2 Test Method A—The third-point loading method is illustrated in Fig. 1. The minimum span between supports shall not be less
than 2.5 multiplied by the average depth of the specimen. The distance between each support and the adjacent distributed point
load shall be one-third of the span length 63 mm [0.1 in.]. Steel rods with a maximum diameter of 25 mm [1 in.] shall be used
to support the specimen and apply the load. The steel rods shall extend over the full width of the specimen and shall have the same
nominal diameter.
NOTE 3—The loading apparatus is intended to be similar to that used in Test Method C78C78/C78M to reduce the need for redundant testing equipment.
5.3 Test Method B—The uniform loading method is illustrated in Fig. 2. The minimum span between supports shall not be less
than 2.5 multiplied by the average depth of the specimen. Uniformly distributed transverse load shall be applied by air pressure
using an air bag over the full surface of the specimen. The air bag reaction frame shall fully contact one surface of the air bag and
shall be sufficiently stiff as to not deflect more than the span divided by 600 during testing.
NOTE 4—Air bags manufactured using 0.5 mm [0.02 in.] thick polyvinyl chloride have been successfully used with this test. When testing specimens
constructed with a high bond-strength mortar, or whose thickness is greater than a nominal 100 mm [4 in.], the applied load required to fail the specimen
FIG. 1 The Third-Point Loading Method (Test Method A)
E518/E518M − 22
FIG. 2 The Uniform Loading Method (Test Method B)
may be such as to rupture the seams of the air bag. In such cases Test Method A is recommended.
6. Sampling and Testing
6.1 Masonry Units—Representative masonry units shall be sampled and tested in accordance with the following applicable
methods: Test Methods C67C67/C67M for brick, or Test Methods C140C140/C140M for concrete masonry units. Minimum tests
required shall be compressive strength, and initial rate of absorption for brick or absorption for concrete masonry units.
6.2 Mortar—One of the types of mortar in Specification C270 shall be used, or the mortar shall conform to that specified for the
construction. Sand sieve analysis shall be performed and recorded, except when ASTM C778 standard sand is used. If ASTM C778
standard sand is used, the record shall identify the sand as 20–30 sand, graded sand, or a blend of indicated proportions of each
sand by weight.
6.2.1 Mortar for prism fabrication shall be mixed to a workable consistency. The compressive strength, initial flow, and water
retention of the mortar shall be determined in accordance with the requirements of Specification C270, except that the cubes
molded for the compressive strength test, after moist curing in the molds for 24 h, shall be released and stored in the same
atmosphere as the prisms as specified in Section 8. The following physical properties of the mortar shall be determined and
recorded:
6.2.2 Compressive strength (average of three cubes),
6.2.3 Initial flow (laboratory-mixed mortar only),
6.2.4 Flow after suction (water retention) (laboratory-mixed mortar only).
7. Test Specimens
7.1 A minimum of five test specimens shall be constructed as stack-bonded prisms, at least 460 mm [18 in.] high with mortar joints
3 1
10 6 1.5 mm [ ⁄8 6 ⁄16 in.] in thickness. The number of courses in each specimen shall be such as to permit locating supports and
loading points midway between joints for Test Method A tests (4, 7, 10, 13, or 16 courses, depending on face heights of units),
and to provide for a span-to-depth ratio that exceeds 2.5. When the test is for the purpose of determining the quality of materials
and workmanship during construction, t
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