ASTM C1072-00a
(Test Method)Standard Test Method for Measurement of Masonry Flexural Bond Strength
Standard Test Method for Measurement of Masonry Flexural Bond Strength
SCOPE
1.1 This test method covers the determination of flexural bond strength of nonreinforced masonry by physical testing of each joint of masonry prisms.
1.2 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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:C1072–00a
Standard Test Method for
Measurement of Masonry Flexural Bond Strength
This standard is issued under the fixed designation C 1072; 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 (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 * unit and mortar properties, workmanship, curing conditions,
coatings on masonry units, or any other factors that may be of
1.1 This test method covers the determination of flexural
concern.
bond strength of nonreinforced masonry by physical testing of
3.3 Flexural bond strength determined by this test method
each joint of masonry prisms.
should not be interpreted as the flexural bond strength of a wall
1.2 This standard does not purport to address all of the
constructed of the same material. However, results may be
safety concerns, if any, associated with its use. It is the
used to predict the flexural strength of a wall. Nor should it be
responsibility of the user of this standard to establish appro-
interpreted as an indication of extent of bond for purposes of
priate safety and health practices and determine the applica-
water permeance evaluation.
bility of regulatory limitations prior to use.
4. Apparatus
2. Referenced Documents
4.1 The test apparatus is shown in Figs. 1-4. The upper and
2.1 ASTM Standards:
lower clamping mechanisms shall be constructed as shown,
C 67 Test Methods of Sampling and Testing Brick and
except that the hex head bolts are permitted to be replaced by
Structural Clay Tile
other tightening devices of equal, or greater, strength and
C 140 Test Methods of Sampling and Testing Concrete
stiffness. The support frame shall be constructed as shown or
Masonry Units
shall be constructed using configurations and materials of
C 270 Specification for Mortar for Unit Masonry
equal, or greater, strength and stiffness. The testing apparatus
C 780 Test Method for Preconstruction and Construction
shall be constructed to apply the load vertically downward on
Evaluation of Mortars for Plain and Reinforced Unit
the upper clamping system in such a manner that the upper and
Masonry
lower clamp do not come in contact during the tests.The prism
C 1357 Test Methods for Evaluating Masonry Bond
2 support system shall be able to accommodate the size of the
Strength
prism to be tested.
3. Significance and Use
5. Sampling and Testing
3.1 This test method is intended to provide a simple and
5.1 Brick Masonry Units—Representative brick masonry
economical means for the determination of comparative values
units shall be sampled and tested in accordance with Test
of flexural bond strength. It may be used either on specimens
Methods C 67.
especially fabricated for bond strength evaluation or on speci-
mens cut from existing masonry.
NOTE 1—Brick properties for which there are methods of test in Test
3.2 The bond strengths determined from this test method Methods C 67 that may be of interest are cold-water absorption, boiling-
water absorption, initial rate of absorption, and compressive strength.
can be used as a means of evaluating the compatibility of
mortars and masonry units. It may also be used to determine
5.2 Concrete Masonry Units—Representative concrete ma-
the effect on flexural bond strength of such factors as masonry
sonry units shall be sampled and tested in accordance withTest
Methods C 140.
5.3 Mortar—When mortar property testing is specified, the
This test method is under the jurisdiction of ASTM Committee C15 on
compressivestrength,aircontent,initialflow,conepenetration,
Manufactured Masonry Units and is the direct responsibility of Subcommittee
C15.04 on Research. and water retention shall be determined in accordance with the
Current edition approved Nov. 10, 2000. Published January 2001. Originally
requirements of Specification C 270 or Test Method C 780.
published as C 1072–93. Last previous edition C 1072–00.
Annual Book of ASTM Standards, Vol 04.05.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C1072–00a
FIG. 1 Bond Wrench Testing Apparatus
6. Test Specimen 6.3.1.6 Generally, all prisms should be cured for 28 days;
however, different periods of time may be used provided the
6.1 The test specimen shall consist of a prism, two or more
relationship between that period and 28 days strength has been
units in height, with a minimum width (b) of 4 in. (see Note 2)
established, or if the effect of age is the parameter being
as shown in Fig. X1.1. Any type of masonry unit and mortar
studied. Prisms fabricated in the laboratory shall be cured in
may be used.
laboratory air. It is recommended that the laboratory air be
NOTE 2—It is recommended that a width (b) of 1 full masonry unit be
maintained at a temperature of 75 6 15°F (24 6 8°C), with a
used. However, full widths may not be possible for samples obtained in
relative humidity between 30 and 70 %. Temperature and
accordance with 6.3.2.
humidity shall be recorded and reported. Closer controls on
6.2 A minimum of five joints shall be tested, using mortar
temperature and humidity (for example, self cure in a plastic
3 1
joints ⁄8 6 ⁄16 in. (9.5 6 1.5 mm) or as specified.
membrane) are permitted, and may result in less variation of
6.3 Prisms may be constructed in a laboratory or in the field
test results.
or may be removed from existing masonry.
NOTE 4—Workmanshipduringfabrication,temperatureofthematerials
6.3.1 Prisms Fabricated in Laboratory or Field:
during fabrication, curing conditions, time between removal from moist
6.3.1.1 Set the first unit of each prism on a firm, horizontal
curing to test, and other factors may affect the bond strengths measured by
surface without the use of mortar.
this test. Standardized specimen fabrication and curing procedures that
NOTE 3—An alignment device may be used to ensure plumbness and attempt to control these variables are prescribed in Test Methods C 1357.
joint thickness uniformity.
6.3.1.7 Whenprismsaremadeduringconstructionatthejob
6.3.1.2 Place a full or face shell mortar bed on all units
site, they shall be constructed in a location where they will not
without furrowing unless the effect of furrowing is being
be disturbed, but will be subjected to atmospheric conditions
studied.
similar to those in the masonry structure whose properties they
6.3.1.3 Immediately place the next course on the mortar bed
are intended to represent.
and tap it to proper level and joint thickness. One face of each
6.3.2 Prisms Obtained from Existing Masonry:
prism shall be in a nearly true plane.
6.3.2.1 Using a portable hand held masonry saw, cut all
6.3.1.4 Repeat 6.3.1.2 and 6.3.1.3 until the prisms are the
edges adjacent to the prism being removed. If embedments are
desired height.Then 1 6 ⁄4 h after completion of construction,
embedded in the intended sample, cut and remove sufficient
place two of the masonry units of the type used to construct the
adjacent masonry to permit cutting the embedments.
prism upon the top course. Identify all specimens using a
6.3.2.2 Identify all samples with a water-resistant marker.
water-resistant marker.
6.3.1.5 Jointsmaybetooledorstruckflush,dependingupon 6.3.2.3 Where mortar fins and extrusions project from the
the desired test conditions. If tooling is required, tool only the specimen to the extent that they may interfere with the
joints on one face of each prism. attachment of the bond wrench, they shall be removed without
C1072–00a
FIG. 2 Bond Wrench Frame and Elevation
causing damage to the specimen. Remove only enough mate- 7.2 Attach the upper clamping bracket to the top brick as
rial to enable proper attachment of the bond wrench. shown in Fig. 1. Tighten each clamping bolt using a torque not
6.3.3 Handling Prisms—Prisms shall receive a minimum of
greater than 50 lbf·in. (5.7 N·m).
handling,andshallbehandledinsuchawaythatthejointswill
7.3 Lower base support away from the bottom of the brick
not be subjected to tensile stresses.
prism so that no contact occurs during testing.
NOTE 5—One method to guard against tension stresses is to use a
7.4 Apply the load at a uniform rate so that the total load is
strapping apparatus (box bander) around the specimen which creates
applied in not less than 1 min or more than 3 min. Measure
compression perpendicular to the bed joints.
load (see Note 6) to an accuracy of 62 % with maximum error
of 5 lbf (22 N).
7. Procedure
7.1 Place the prism vertically in the support frame as shown
NOTE 6—The load indicated in Fig. 1 may be applied by any means,
in Fig. 1, and clamp firmly into a locked position using the
such as a testing machine, hydraulic jack, dead weights, etc. but must be
lower clamping bracket. Orient the prism so that the face of the
within 63° of vertical. Load may be measured u
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