ASTM C140/C140M-14b
(Test Method)Standard Test Methods for Sampling and Testing Concrete Masonry Units and Related Units
Standard Test Methods for Sampling and Testing Concrete Masonry Units and Related Units
SIGNIFICANCE AND USE
4.1 These test methods provide general testing requirements for application to a broad range of concrete products. Those general testing requirements are included in the body of this standard.
Note 2: Consult manufacturer, supplier, product specifications, or other resources for more specific measurement or testing guidelines for those products not addressed with the annex of this standard.
4.2 These test methods provide specific testing requirements in two distinct sections, the requirements applicable to all units covered by these test methods and those applicable to the specific unit types. The requirements applicable to all units are included in the body of these test methods and those applicable to the specific unit types are included within the annexes.
SCOPE
1.1 These test methods provide various testing procedures commonly used for evaluating characteristics of concrete masonry units and related concrete units. Methods are provided for sampling, measurement of dimensions, compressive strength, absorption, unit weight (density), moisture content, flexural load, and ballast weight. Not all methods are applicable to all unit types, however.
1.2 Specific testing and reporting procedures are included in annexes to these test methods for the following specific unit types:
Annex A1—Concrete masonry units (Specifications C90, C129)
Annex A2—Concrete and calcium silicate brick
(Specifications C55, C73, C1634)
Annex A3—Segmental retaining wall units (Specification C1372)
Annex A4—Concrete interlocking paving units
(Specification C936/C936M)
Annex A5—Concrete grid paving units (Specification C1319)
Annex A6—Concrete roof pavers (Specification C1491)
Annex A7—Dry-cast articulating concrete block
(Specification D6684)
1.3 The test procedures included in these test methods are also applicable to other types of units not referenced in these test methods, but specific testing and reporting requirements for those units are not included.
1.4 These test methods include the following sections:
Section
Scope
1
Referenced Documents
2
Terminology
3
Significance and Use
4
Sampling
5
Measurement of Dimensions
6
Compressive Strength
7
Absorption
8
Calculations
9
Report
10
Keywords
11
Annexes—Test Procedures
Concrete Masonry Units
Annex A1
Concrete and Calcium Silicate Brick
Annex A2
Segmental Retaining
Wall Units
Annex A3
Concrete Interlocking Paving Units
Annex A4
Concrete Grid Paving
Units
Annex A5
Concrete Roof Pavers
Annex A6
Dry-Cast Articulating
Concrete Block
Annex A7
Determining Plate Thickness
Requirements for
Compression Testing
Annex A8
Worksheet and Test Report for
Concrete Masonry Units
Appendix X1
Note 1: The testing laboratory performing these test methods should be evaluated in accordance with Practice C1093.
1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. 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 non-conformance with the standard.
1.6 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: C140/C140M − 14b
StandardTest Methods for
Sampling and Testing Concrete Masonry Units and Related
Units
This standard is issued under the fixed designation C140/C140M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.
A superscript 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.
1. Scope*
Section
Annexes—Test Procedures
1.1 These test methods provide various testing procedures
Concrete Masonry Units Annex A1
commonly used for evaluating characteristics of concrete Concrete and Calcium Silicate Brick Annex A2
Segmental Retaining Annex A3
masonryunitsandrelatedconcreteunits.Methodsareprovided
Wall Units
for sampling, measurement of dimensions, compressive
Concrete Interlocking Paving Units Annex A4
strength, absorption, unit weight (density), moisture content, Concrete Grid Paving Annex A5
Units
flexural load, and ballast weight. Not all methods are appli-
Concrete Roof Pavers Annex A6
cable to all unit types, however.
Dry-Cast Articulating Annex A7
Concrete Block
1.2 Specifictestingandreportingproceduresareincludedin
Determining Plate Thickness Annex A8
annexes to these test methods for the following specific unit
Requirements for
Compression Testing
types:
Worksheet and Test Report for Appendix X1
Annex A1—Concrete masonry units (Specifications C90, C129)
Concrete Masonry Units
Annex A2—Concrete and calcium silicate brick
NOTE 1—The testing laboratory performing these test methods should
(Specifications C55, C73, C1634)
Annex A3—Segmental retaining wall units (Specification C1372) be evaluated in accordance with Practice C1093.
Annex A4—Concrete interlocking paving units
1.5 The values stated in either SI units or inch-pound units
(Specification C936/C936M)
Annex A5—Concrete grid paving units (Specification C1319)
are to be regarded separately as standard. The values stated in
Annex A6—Concrete roof pavers (Specification C1491)
each system may not be exact equivalents; therefore, each
Annex A7—Dry-cast articulating concrete block
system shall be used independently of the other. Combining
(Specification D6684)
values from the two systems may result in non-conformance
1.3 The test procedures included in these test methods are
with the standard.
also applicable to other types of units not referenced in these
1.6 This standard does not purport to address all of the
test methods, but specific testing and reporting requirements
safety concerns, if any, associated with its use. It is the
for those units are not included.
responsibility of the user of this standard to establish appro-
1.4 These test methods include the following sections:
priate safety and health practices and determine the applica-
Section
bility of regulatory limitations prior to use.
Scope 1
Referenced Documents 2
Terminology 3
2. Referenced Documents
Significance and Use 4
2.1 ASTM Standards:
Sampling 5
Measurement of Dimensions 6
C55Specification for Concrete Building Brick
Compressive Strength 7
C73Specification for Calcium Silicate Brick (Sand-Lime
Absorption 8
Calculations 9 Brick)
Report 10
C90Specification for Loadbearing Concrete Masonry Units
Keywords 11
C129Specification for Nonloadbearing Concrete Masonry
Units
These test methods are under the jurisdiction of ASTM Committee C15 on
Manufactured Masonry Units and are the direct responsibility of Subcommittee
C15.03 on Concrete Masonry Units and Related Units. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Dec. 15, 2014. Published January 2015. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1938. Last previous edition approved in 2014 as C140–14a. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/C0140_C0140M-14B. the ASTM website.
*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
C140/C140M − 14b
C143/C143MTest Method for Slump of Hydraulic-Cement 5.4 Identification—Mark each specimen so that it may be
Concrete identified at any time. Markings shall cover not more than 5%
C936/C936MSpecification for Solid Concrete Interlocking of the surface area of the specimen.
Paving Units
5.5 Received Weight—Weigh each specimen immediately
C1093Practice for Accreditation of Testing Agencies for
after sampling and marking, and record as W (received
r
Masonry
weight). Record time and place W was measured.
r
C1232Terminology of Masonry
NOTE 4—Received weights often have direct relationships with other
C1319Specification for Concrete Grid Paving Units
unit properties and are therefore a useful method of evaluating results or
C1372Specification for Dry-Cast Segmental RetainingWall
for sorting purposes. The weight of a concrete masonry unit and related
Units
unit changes with time and exposure conditions, primarily as a result of
C1491Specification for Concrete Roof Pavers
the moisture within the unit. Therefore, to understand the context of a
received weight value, it is also important to understand the point in time
C1552Practice for Capping Concrete Masonry Units, Re-
and the frame of reference when that weight was determined. “Time and
lated Units and Masonry Prisms for Compression Testing
place” should not refer to when and where the unit was sampled but when
C1634Specification for Concrete Facing Brick
and where the received weights were determined. In addition to date and
D6684Specification for Materials and Manufacture of Ar-
time references, it is also important to know if those weights were
ticulating Concrete Block (ACB) Revetment Systems
determined after units reached equilibrium with lab environment, or
before units were shipped, or after delivery to the job site, and so forth.
E4Practices for Force Verification of Testing Machines
E6Terminology Relating to Methods of Mechanical Testing
6. Measurement of Dimensions
3. Terminology
6.1 Apparatus:
6.1.1 Measurement Devices—Devices used to measure
3.1 Terminology defined in Terminologies C1232 and E6
specimen dimensions shall have divisions not greater than
shall apply for these test methods.
0.1in. [2.5mm] when the dimension is to be reported to the
3.2 Definitions of Terms Specific to This Standard:
nearest 0.1 in. [2.5 mm] and not greater than 0.01 in.
3.2.1 lot, n—any number of concrete masonry units or
[0.25mm] when the dimension is to be reported to the nearest
related units, designated by the producer, of any configuration
0.01 in. [0.25 mm].
or dimension manufactured by the producer using the same
6.1.2 Measuring devices shall be readable and accurate to
materials, concrete mix design, manufacturing process, and
the division required to be reported.Accuracy shall be verified
curing method.
at least once annually. Verification record shall include date of
verification, person or agency performing verification, identi-
4. Significance and Use
fication of reference standard used, test points used during
4.1 Thesetestmethodsprovidegeneraltestingrequirements
verification, and readings at test points.
for application to a broad range of concrete products. Those
6.2 Specimens—Three full-size units shall be selected for
general testing requirements are included in the body of this
measurement of dimensions.
standard.
NOTE 2—Consult manufacturer, supplier, product specifications, or
6.3 Measurements—Measure specimens in accordance with
other resources for more specific measurement or testing guidelines for
the applicable annex of this standard. For those products not
those products not addressed with the annex of this standard.
covered by the annexes of this standard, measure overall
4.2 Thesetestmethodsprovidespecifictestingrequirements
dimensions (width, height, length) in at least two locations on
intwodistinctsections,therequirementsapplicabletoallunits
opposite sides of the specimen to the nearest division required
covered by these test methods and those applicable to the
to be reported. Document location of each measurement on a
specific unit types.The requirements applicable to all units are
sketch or photograph of the specimen.
includedinthebodyofthesetestmethodsandthoseapplicable
NOTE 5—Specimens used for measurement of dimensions may be used
to the specific unit types are included within the annexes.
in other tests.
NOTE 6—Calipers, micrometers, and steel scales and dividers of the
5. Sampling
appropriate accuracy and readability have been shown to be adequate for
5.1 Selection of Test Specimens:
these measurements.
5.1.1 For purposes of testing, full-sized units shall be
7. Compressive Strength
selected by the purchaser or authorized representative. The
7.1 Test Apparatus:
selected specimens shall be of similar configuration and
dimensions. Specimens shall be representative of the whole lot 7.1.1 Thetestingmachineshallhaveanaccuracyof 61.0%
over the anticipated load range. The upper platen shall be a
of units from which they are selected.
spherically seated, hardened metal block firmly attached at the
5.2 Number of Specimens:
center of the upper head of the machine. The center of the
5.2.1 Unless specified otherwise in the applicable annex, a
sphere shall lie at the center of the surface held in its spherical
set of units shall consist of six full-size units.
seat but shall be free to turn in any direction, and its perimeter
5.3 Remove loose material from the specimens (including
shall have at least 0.25 in. [6 mm] clearance from the head to
the cores) prior to determining the received weight.
accommodate specimens whose bearing surfaces are not par-
allel. The diameter of the upper platen (determined in accor-
NOTE 3—An abrasive stone or wire brush is typically used to remove
loose material. dance with Annex A8) shall be at least 6 in. [150 mm]. A
C140/C140M − 14b
the same net volume as units used for compression testing. Sampled split
hardened metal bearing plate may be used beneath the speci-
face units, which have irregular surfaces, should be divided at the time
men to minimize wear of the lower platen of the machine.
theyaresampledfromthelot,suchthattheabsorptiontestspecimenshave
7.1.2 When the bearing area of the upper platen or lower
a net volume that is visually representative and a weight that is
platen is not sufficient to cover the area of the specimen, a
representative of the compression test specimens.
single steel plate with a thickness equal to at least the distance
7.2.4 Where saw-cutting of test specimens is allowed or
from the edge of the platen to the most distant corner of the
required by the standard or applicable annex, sawing shall be
specimen shall be placed between the platen and the capped
performed in an accurate, competent manner, subjecting the
specimen. The length and width of the steel plate shall be at
specimen to as little saw vibration as possible. Use a diamond
least 0.25 in. [6 mm] greater than the length and width of the
saw blade of proper hardness. Following cutting, residue from
units.
the cutting operation shall be removed prior to continuing
7.1.3 Thesurfacesoftheplatenorplateintendedforcontact
testing (see Note 10). If the specimen is wetted during sawing,
with the specimen shall have a hardness not less than HRC 60
allow the specimen to dry to equilibrium with laboratory air
(BHN 620). The surfaces of the platen and plate shall not
conditions before testing, using the procedures outlined in
depart from plane surfaces by more than 0.001 in. [0.025 mm]
7.2.3.
in any 6 in. [150 mm] dimension.
NOTE 10—For specimens cut with a wet saw, rinsing with clean water
NOTE 7—Research has shown that thickness of bearing plates has a
istypicallysufficientforremovingcuttingresidue.Forspecimenscutwith
significant effect on the tested compressive strength of masonry units
a dry saw, brushing with a soft-bristle brush is typically sufficient for
whenthebearingareaoftheplatenisnotsufficienttocovertheareaofthe
removing cutting residue.
specimen.Platebendingresultsinnonuniformstressdistributionsthatcan
7.2.5 Ifcompressiontestspecimenshavebeensaw-cutfrom
influence the failure mechanisms of the tested specimens. The magnitude
of this effect is controlled by the stiffness of the plate, the size of the full-sized units and the net area of the compression test
specimen tested, and the strength of the specimen. Tested compressive
specimens can not be determined by 9.4.1, saw-cut an addi-
strengths will typically increase with increased plate thickness and with
tional three units to the dimensions and configuration of the
reduced distance to the furthest corner of the specimen. Some testing
three compression test specimens.The average net area for the
laboratories have limitations that limit the practicality of eliminating plate
saw-cut compression specimens shall be taken as the average
bending entirely. Therefore the plate thickness requirements in 7.1 are
intended to provide an adequate level of accuracy in the compression test net area of the additional three saw-cut units calculated as
results so as to conform to the limits of practicality of the testing
required in 9.4. Calculated net volumes of saw-cut specimens
laboratory.
shall not be used in calculating equivalent thickness.
NOTE 8—Annex A8 includes guidance on determining the required
platethicknessbasedontheconfigurationofthetestspecimenandthetest 7.3 Capping—Cap test specimens in accordance with Prac-
machine.
tice C1552.
7.1.4 The testing machine shall be verified in accordance
7.4 Compression Testing Procedure:
with Practices E4 at a frequency defined by Practice C1093.
7.4.1 Position of Specimens—Test specimens with the cen-
troidoftheirbearingsurfacesalignedverticallywiththecenter
7.2 Test Specimens:
of thrust of the spherically seated steel bearing block of the
7.2.1 Unless specified otherwise in the applicable annex,
testingmachine(Note11).Exceptforspecialunitsintendedfor
test three specimens in compression.
use with their cores in a horizontal direction, test all hollow
7.2.2 Unless specified otherwise in the applicable annex,
concrete masonry units with their cores in a vertical direction.
specimens shall be full-sized units except when the units
Test masonry units that are 100% solid and special hollow
cannot be tested full-size due to specimen configuration or
units intended for use with their hollow cores in a horizontal
testing machine requirements. In these cases, reduce the
direction in the same direction as in service. Prior to testing
specimen size in accordanc
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it 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 version
of the standard as published by ASTM is to be considered the official document.
Designation: C140/C140M − 14a C140/C140M − 14b
Standard Test Methods for
Sampling and Testing Concrete Masonry Units and Related
Units
This standard is issued under the fixed designation C140/C140M; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope*
1.1 These test methods provide various testing procedures commonly used for evaluating characteristics of concrete masonry
units and related concrete units. Methods are provided for sampling, measurement of dimensions, compressive strength,
absorption, unit weight (density), moisture content, flexural load, and ballast weight. Not all methods are applicable to all unit
types, however.
1.2 Specific testing and reporting procedures are included in annexes to these test methods for the following specific unit types:
Annex A1—Concrete masonry units (Specifications C90, C129)
Annex A2—Concrete and calcium silicate brick
(Specifications C55, C73, C1634)
Annex A3—Segmental retaining wall units (Specification C1372)
Annex A4—Concrete interlocking paving units
(Specification C936/C936M)
Annex A5—Concrete grid paving units (Specification C1319)
Annex A6—Concrete roof pavers (Specification C1491)
Annex A7—Dry-cast articulating concrete block
(Specification D6684)
1.3 The test procedures included in these test methods are also applicable to other types of units not referenced in these test
methods, but specific testing and reporting requirements for those units are not included.
1.4 These test methods include the following sections:
Section
Scope 1
Referenced Documents 2
Terminology 3
Significance and Use 4
Sampling 5
Measurement of Dimensions 6
Compressive Strength 7
Absorption 8
Calculations 9
Report 10
Keywords 11
These test methods are under the jurisdiction of ASTM Committee C15 on Manufactured Masonry Units and are the direct responsibility of Subcommittee C15.03 on
Concrete Masonry Units and Related Units.
Current edition approved July 1, 2014Dec. 15, 2014. Published August 2014January 2015. Originally approved in 1938. Last previous edition approved in 2014 as
C140 – 14.C140 – 14a. DOI: 10.1520/C0140_C0140M-14A.10.1520/C0140_C0140M-14B.
*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
C140/C140M − 14b
Section
Annexes—Test Procedures
Concrete Masonry Units Annex A1
Concrete and Calcium Silicate Brick Annex A2
Segmental Retaining Annex A3
Wall Units
Concrete Interlocking Paving Units Annex A4
Concrete Grid Paving Annex A5
Units
Concrete Roof Pavers Annex A6
Dry-Cast Articulating Annex A7
Concrete Block
Determining Plate Thickness Annex A8
Requirements for
Compression Testing
Worksheet and Test Report for Appendix X1
Concrete Masonry Units
NOTE 1—The testing laboratory performing these test methods should be evaluated in accordance with Practice C1093.
1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. 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 non-conformance with the standard.
1.6 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.
2. Referenced Documents
2.1 ASTM Standards:
C55 Specification for Concrete Building Brick
C73 Specification for Calcium Silicate Brick (Sand-Lime Brick)
C90 Specification for Loadbearing Concrete Masonry Units
C129 Specification for Nonloadbearing Concrete Masonry Units
C143/C143M Test Method for Slump of Hydraulic-Cement Concrete
C936/C936M Specification for Solid Concrete Interlocking Paving Units
C1093 Practice for Accreditation of Testing Agencies for Masonry
C1232 Terminology of Masonry
C1319 Specification for Concrete Grid Paving Units
C1372 Specification for Dry-Cast Segmental Retaining Wall Units
C1491 Specification for Concrete Roof Pavers
C1552 Practice for Capping Concrete Masonry Units, Related Units and Masonry Prisms for Compression Testing
C1634 Specification for Concrete Facing Brick
D6684 Specification for Materials and Manufacture of Articulating Concrete Block (ACB) Revetment Systems
E4 Practices for Force Verification of Testing Machines
E6 Terminology Relating to Methods of Mechanical Testing
3. Terminology
3.1 Terminology defined in Terminologies C1232 and E6 shall apply for these test methods.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 lot, n—any number of concrete masonry units or related units, designated by the producer, of any configuration or
dimension manufactured by the producer using the same materials, concrete mix design, manufacturing process, and curing
method.
4. Significance and Use
4.1 These test methods provide general testing requirements for application to a broad range of concrete products. Those general
testing requirements are included in the body of this standard.
NOTE 2—Consult manufacturer, supplier, product specifications, or other resources for more specific measurement or testing guidelines for those
products not addressed with the annex of this standard.
4.2 These test methods provide specific testing requirements in two distinct sections, the requirements applicable to all units
covered by these test methods and those applicable to the specific unit types. The requirements applicable to all units are included
in the body of these test methods and those applicable to the specific unit types are included within the annexes.
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.
C140/C140M − 14b
5. Sampling
5.1 Selection of Test Specimens:
5.1.1 For purposes of testing, full-sized units shall be selected by the purchaser or authorized representative. The selected
specimens shall be of similar configuration and dimensions. Specimens shall be representative of the whole lot of units from which
they are selected.
5.2 Number of Specimens:
5.2.1 Unless specified otherwise in the applicable annex, a set of units shall consist of six full-size units.
5.2.2 Unless specified otherwise in the applicable annex, for the compressive strength, absorption, unit weight (density), and
moisture content determinations, one set of units shall be selected from each lot of 10 000 units or fraction thereof and two sets
of units from each lot of more than 10 000 and less than 100 000 units. For lots of more than 100 000 units, one set of units shall
be selected from each 50 000 units or fraction thereof contained in the lot. Additional specimens shall be taken if directed by the
purchaser.
5.3 Remove loose material from the specimens (including the cores) prior to determining the received weight.
NOTE 3—An abrasive stone or wire brush is typically used to remove loose material.
5.4 Identification—Mark each specimen so that it may be identified at any time. Markings shall cover not more than 5 % of the
surface area of the specimen.
5.5 Received Weight—Weigh each specimen immediately after sampling and marking, and record as W (received weight).
r
Record time and place W was measured.
r
NOTE 4—Received weights often have direct relationships with other unit properties and are therefore a useful method of evaluating results or for
sorting purposes. The weight of a concrete masonry unit and related unit changes with time and exposure conditions, primarily as a result of the moisture
within the unit. Therefore, to understand the context of a received weight value, it is also important to understand the point in time and the frame of
reference when that weight was determined. “Time and place” should not refer to when and where the unit was sampled but when and where the received
weights were determined. In addition to date and time references, it is also important to know if those weights were determined after units reached
equilibrium with lab environment, or before units were shipped, or after delivery to the job site, and so forth.
6. Measurement of Dimensions
6.1 Apparatus:
6.1.1 Measurement Devices—Devices used to measure specimen dimensions shall have divisions not greater than 0.1 in.
[2.5 mm] when the dimension is to be reported to the nearest 0.1 in. [2.5 mm] and not greater than 0.01 in. [0.25 mm] when the
dimension is to be reported to the nearest 0.01 in. [0.25 mm].
6.1.2 Measuring devices shall be readable and accurate to the division required to be reported. Accuracy shall be verified at least
once annually. Verification record shall include date of verification, person or agency performing verification, identification of
reference standard used, test points used during verification, and readings at test points.
6.2 Specimens—Three full-size units shall be selected for measurement of dimensions.
6.3 Measurements—Measure specimens in accordance with the applicable annex of this standard. For those products not
covered by the annexes of this standard, measure overall dimensions (width, height, length) in at least two locations on opposite
sides of the specimen to the nearest division required to be reported. Document location of each measurement on a sketch or
photograph of the specimen.
NOTE 5—Specimens used for measurement of dimensions may be used in other tests.
NOTE 6—Calipers, micrometers, and steel scales and dividers of the appropriate accuracy and readability have been shown to be adequate for these
measurements.
7. Compressive Strength
7.1 Test Apparatus:
7.1.1 The testing machine shall have an accuracy of 61.0 % over the anticipated load range. The upper platen shall be a
spherically seated, hardened metal block firmly attached at the center of the upper head of the machine. The center of the sphere
shall lie at the center of the surface held in its spherical seat but shall be free to turn in any direction, and its perimeter shall have
at least 0.25 in. [6 mm] clearance from the head to accommodate specimens whose bearing surfaces are not parallel. The diameter
of the upper platen (determined in accordance with Annex A8) shall be at least 6 in. [150 mm]. A hardened metal bearing plate
may be used beneath the specimen to minimize wear of the lower platen of the machine.
7.1.2 When the bearing area of the upper platen or lower platen is not sufficient to cover the area of the specimen, a single steel
plate with a thickness equal to at least the distance from the edge of the platen to the most distant corner of the specimen shall
be placed between the platen and the capped specimen. The length and width of the steel plate shall be at least 0.25 in. [6 mm]
greater than the length and width of the units.
C140/C140M − 14b
7.1.3 The surfaces of the platen or plate intended for contact with the specimen shall have a hardness not less than HRC 60
(BHN 620). The surfaces of the platen and plate shall not depart from plane surfaces by more than 0.001 in. [0.025 mm] in any
6 in. [150 mm] dimension.
NOTE 7—Research has shown that thickness of bearing plates has a significant effect on the tested compressive strength of masonry units when the
bearing area of the platen is not sufficient to cover the area of the specimen. Plate bending results in nonuniform stress distributions that can influence
the failure mechanisms of the tested specimens. The magnitude of this effect is controlled by the stiffness of the plate, the size of the specimen tested,
and the strength of the specimen. Tested compressive strengths will typically increase with increased plate thickness and with reduced distance to the
furthest corner of the specimen. Some testing laboratories have limitations that limit the practicality of eliminating plate bending entirely. Therefore the
plate thickness requirements in 7.1 are intended to provide an adequate level of accuracy in the compression test results so as to conform to the limits
of practicality of the testing laboratory.
NOTE 8—Annex A8 includes guidance on determining the required plate thickness based on the configuration of the test specimen and the test machine.
7.1.4 The testing machine shall be verified in accordance with Practices E4 at a frequency defined by Practice C1093.
7.2 Test Specimens:
7.2.1 Unless specified otherwise in the applicable annex, test three specimens in compression.
7.2.2 Unless specified otherwise in the applicable annex, specimens shall be full-sized units except when the units cannot be
tested full-size due to specimen configuration or testing machine requirements. In these cases, reduce the specimen size in
accordance with Annex A1.
7.2.3 After delivery to the laboratory, store compression specimens (unstacked and separated by not less than 0.5 in. [13 mm]
on all sides) continuously in air at a temperature of 75 6 15°F [24 6 8°C] and a relative humidity of less than 80 % for not less
than 48 h. Alternatively, if compression results are required sooner, store units unstacked in the same environment described above
with a current of air from an electric fan passing over them for a period of not less than 4 h. Continue passing air over the specimens
until two successive weighings at intervals of 2 h show an increment of loss not greater than 0.2 % of the previously determined
weight of the specimen and until no moisture or dampness is visible on any surface of the unit. Specimens shall not be subjected
to oven-drying.
NOTE 9—In this test method, net area (other than certain solid units, see 9.4) is determined from specimens other than those subjected to compression
testing. The compressive strength method is based on the assumption that units used for determining net volume (absorption specimens) have the same
net volume as units used for compression testing. Sampled split face units, which have irregular surfaces, s
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