ASTM C952-91(1997)e1
(Test Method)Standard Test Method for Bond Strength of Mortar to Masonry Units
Standard Test Method for Bond Strength of Mortar to Masonry Units
SCOPE
1.1 This test method provides two procedures for measuring bond strength of mortar to masonry units: a crossed brick couplet tensile test for evaluating mortar-brick bonding and a stacked-bond, flexural test for evaluating mortar-concrete block bonding.
1.2 This standard does not purport to address the safety problems 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.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
e1
Designation: C 952 – 91 (Reapproved 1997)
Standard Test Method for
Bond Strength of Mortar to Masonry Units
This standard is issued under the fixed designation C 952; 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.
e NOTE—Section 13 on Keywords was added editorally in November 1997.
1. Scope commercial masonry construction. The bonding in commer-
cially built structures is determined by many factors beyond the
1.1 This test method provides two procedures for measuring
characteristics of mortar, masonry units, and the procedures of
bond strength of mortar to masonry units: a crossed brick
this test method.
couplet tensile test for evaluating mortar-brick bonding and a
stacked-bond, flexural test for evaluating mortar-concrete
PREPARATION AND TESTING OF FRESH MORTAR
block bonding.
1.2 This standard does not purport to address the safety
4. Preparation of Mortar
concerns, if any, associated with its use. It is the responsibility
4.1 Apparatus:
of the user of this standard to establish appropriate safety and
4.1.1 Scales, Weights, and Glass Graduates conforming to
health practices and determine the applicability of regulatory
2.1, 2.2, and 2.4 of Test Method C 190 except that the scales
limitations prior to use.
and scale weights shall be of suitable capacity.
4.1.2 Mixer, Paddle, Mixing Bowl, and Scraper conforming
2. Referenced Documents
to 2.1 to 2.4, of Method C 305 except that the mixer, paddle,
2.1 ASTM Standards:
and mixing bowl shall have a capacity of 10 qt (0.01 m ) and
C 67 Test Methods of Sampling and Testing Brick and
the first or slow speed of the mixer shall revolve the paddle at
Structural Clay Tile
a rate of 144 6 5 rpm, with a planetary speed of approximately
C 91 Specification for Masonry Cement
61 rpm. The second speed shall revolve the paddle at a rate of
C 109 Test Method for Compressive Strength of Hydraulic
258 6 10 rpm, with a planetary motion of approximately 109
Cement Mortars (Using 2-in. or 50-mm Cube Specimens)
rpm.
C 190 Test Method for Tensile Strength of Hydraulic Ce-
4.1.3 Stop Clock.
ment Mortars
4.2 Procedure:
C 230 Specification for Flow Table for Use in Tests of
4.2.1 Weigh or measure the proper quantities of aggregates
Hydraulic Cement
(Note 1), cementing materials, and water needed for the batch.
C 270 Specification for Mortar for Unit Masonry
The amount of water used shall provide a mortar of wet
C 305 Practice for Mechanical Mixing of Hydraulic Cement
consistency, and the mortar shall preferably be as wet as can
Pastes and Mortars of Plastic Consistency
conveniently be handled with a mason’s trowel.
C 427 Test Method for Moisture Condition of Hardened
NOTE 1—About 400 g of aggregate will provide sufficient mortar for
Concrete by the Relative Humidity Method
several bond test specimens.
3. Significance and Use
4.2.2 Charge the mixing bowl with the measured amounts of
3.1 These procedures are useful for research into bonding of
aggregate and cementing material. Mix manually with a spoon
masonry. They are not intended to predict the bond strength of
for 5 s. Insert the paddle into the mixture. Preset the stop clock
to 10 s before zero time. Set the mixer at No. 1 (slow) speed,
approximately 144 rpm.
This test method is under the jurisdiction of ASTM Committee C15 on
4.2.3 Simultaneously start the stop clock and the mixer. Mix
Manufactured Masonry Units and is the direct responsibility of Subcommittee
C15.04 on Research. Committee E-6 maintains a continued interest in these for 10 s.
practices and will make use of them in the future.
Current edition approved April 15, 1991. Published June 1991. Originally
published as E 149 – 59 T. Redesignated C 952 – 76 in 1981. Last previous edition
C 952 – 86.
Annual Book of ASTM Standards, Vol 04.05.
3 5
Annual Book of ASTM Standards, Vol 04.01. The Model C100 mixer manufactured by the Hobart Mfg. Co., Troy, OH has
Discontinued, see 1980 Annual Book of ASTM Standards, Part 16. been found satisfactory for this purpose.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
e1
C 952 – 91 (1997)
4.2.4 At zero time and at a continuing slow speed, add the specimens. After mortar for bond test specimens has been
major portion (approximately 95 %) of the mixing water within taken from the board, determine the air content of the mortar
10 s. Continue mixing for an additional 10 s. remaining on the board.
4.2.5 Stop the mixer. Change quickly to No. 2 (fast) speed 7.2.2 Final—Determine the weight of 400 mL of mortar as
(about 260 rpm) and resume mixing. Continue mixing for a specified in 20.1 of Specification C 91, except that the mortar
total of 2 min elapsed time starting from zero time. is not necessarily tempered to an initial flow of 110 %.
4.2.6 Stop the mixer. Let the mortar stand in the bowl for 10 7.3 Calculation—Calculate the air content of the mortar in
min with the bowl covered with a slotted lid, permitting the accordance with Section 22 of Specification C 91, except that
paddle to remain in the mortar. Before placement of the lid the specific gravity of the sand (value S in the equation) shall
within the first 15 s of the 10-min waiting period, quickly be that of the sand used in the mortar.
scrape down into the batch with a rubber scraper any mortar
8. Compressive Strength of Mortar
that may have collected on the side of the bowl.
8.1 Apparatus—Specimen molds, tamper, trowel, and test-
NOTE 2—If the mortar is one that tends to segregate and in which the
ing machine conforming to 3.5, 3.8, 3.9, and 3.10 of Test
fines stick to the bottom of the bowl, the paddle may be temporarily
Method C 109.
removed and the scraper applied to the extreme bottom of the bowl to
bring up such fines as may have adhered to the bowl bottom. 8.2 Procedure—Preparation of specimen molds and mold-
ing of test specimens shall conform to Sections 7 and 8.4 of
4.2.7 Remove the cover, change to No. 1 (slow) speed, and
Method C 109. Fill the molds after determination of the weight
mix for 30 s. Add the remainder of the mixing water during the
of 400 mL of the mortar in accordance with 5.2.2 of this test
first part of this 30-s interval. Stop the mixer, change promptly
method.
to No. 2 (fast) speed, and finish by mixing for an additional 30
8.3 Storage of Test Specimens—Store mortar cubes in
s.
accordance with 11.2.2 of Specification C 270.
5. Initial Flow of Mortar
PREPARATION AND TESTING OF BOND STRENGTH
5.1 Apparatus—The flow table and flow mold shall con-
TEST SPECIMENS
form to the requirements of Specification C 230.
5.2 Procedure—Immediately after final mixing of the mor-
9. Apparatus
tar, determine the initial flow of mortar from the bowl in
9.1 Miscellaneous—Brass-covered mortar board 18 in. (457
accordance with 8.3 of Test Method C 109 excepting the
mm) square, an 11-in. (279-mm) long mason’s trowel, labora-
reference to trial mortars at the end of that section. Discard that
tory trowel with straight edges, short handled spoon or scoop
portion of the mortar used to determine the initial flow.
of ⁄4-cup (0.5-dm ) capacity, steel straightedge 10 in. (254
1 5
NOTE 3—The high flow of some mortars makes it advisable to drop the
mm) long, metal mold ⁄2 in. (13 mm) deep with 3 ⁄8-in.
table less than 25 drops before measuring the flow. When calculating the
(92-mm) square opening beveled to slope of 0.08 (total 0.04),
initial flow for 25 drops of such mortars, the measured flow should be
splash board (Fig. 1) with handle 20 in. (508 mm) long and 3
increased by adding two percentage points of flow for each drop of the
in. (76 mm) wide.
table less than 25.
9.2 Drop Hammer for crossed-brick couplets (Fig. 2, Table
1).
6. Water Retention of Mortar
9.3 Drop Hammer for block assemblies (Fig. 3).
6.1 Apparatus—Water retention apparatus shall conform to
9.4 Loading Jigs for crossed-brick couplets (Fig. 4).
the requirements for the apparatus in Section 25 of Specifica-
9.5 Frames (Fig. 5) for testing block assemblies: upper
tion C 91.
frame fitted with ball bearing mounted 10 in. (254 mm) from
6.2 Procedure—Immediately after measuring the initial
vertical axis of specimen for eccentric application of vertical
flow, remix the mortar remaining in the bowl for 15 s; then
load. Fig. .
determine the flow after suction and the water retention of the
9.6 Torque Wrench.
mortar in accordance with the requirements of Sections 28 and
29 of Specification C 91.
10. Crossed-Brick Couplets
NOTE 4—The number of drops of the flow table shall be the same as
10.1 Brick—Test specimens consisting of crossed-brick
that used to determine the initial flow and, excepting that the mortar is not
couplets may be used to determine:
necessarily tempered to an initial flow of 110 % and that the mortar used
10.1.1 Bond between specified brick and a specified mortar,
for determining the initial flow is discarded and not returned to mixing
10.1.2 Relative bond between different brick and a specified
bowl, the procedure shall be in accordance with the specified require-
mortar, or
ments.
10.1.3 Relative bond between a specified brick and different
7. Air Content of Mortar
mortars.
7.1 Apparatus—Measure, straightedge, spatula, and other 10.1.4 In each case, the initial rate of absorption of the brick
needed apparatus conforming to 18.1 of Specification C 91. shall be determined in accordance with Section 29 of Methods
7.2 Procedure: C 67. For 10.1.1, the brick used for couplets should include the
7.2.1 Preliminary—Place the mortar remaining in the mix- full range of absorption rates acceptable under the specifica-
ing bowl after filling the suction cup for water retention test on tions. For 10.1.3, absorption rates of the brick should be limited
a mortar board and use for the fabrication of bond test to a range of 15 g.
NOTICE: This standard has either been superceded and replaced by a new ver
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.