ASTM C947-03(2023)

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.
Designation: C947 − 03 (Reapproved 2023)
Standard Test Method for
Flexural Properties of Thin-Section Glass-Fiber-Reinforced
Concrete (Using Simple Beam With Third-Point Loading)
This standard is issued under the fixed designation C947; 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 products, ascertaining compliance with the governing
specifications, research and development, and generating data
1.1 This test method covers determination of the flexural
for use in product design.
ultimate strength in bending and the yield strength of glass-
fiber reinforced concrete sections by the use of a simple beam
4. Apparatus
of 1.0 in. (25.4 mm) or less in depth using third-point loading.
4.1 Testing Machine—A properly calibrated testing machine
1.2 The values stated in inch-pound units are to be regarded
that can be operated at constant rates of crosshead motion and
as the standard. The values given in parentheses are for
in which the error in the force measuring system shall not
information only.
exceed 61.0 % of the maximum force expected to be measured
shall be used. The testing machine shall be equipped with a
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the deflection measuring and recording device. The stiffness of the
testing machine shall be such that the total elastic deformation
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter- of the system does not exceed 1.0 % of the total deflection of
the test specimen during the test, or appropriate corrections
mine the applicability of regulatory limitations prior to use.
shall be made. The force-indicating mechanism shall be
1.4 This international standard was developed in accor-
essentially free of inertial lag at the crosshead rate used. The
dance with internationally recognized principles on standard-
accuracy of the testing machine shall be verified in accordance
ization established in the Decision on Principles for the
with Practices E4 and Specification D76/D76M.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
4.2 Loading Noses and Supports—The loading noses and
Barriers to Trade (TBT) Committee.
supports shall have cylindrical surfaces. In order to avoid
excessive indentation or failure due to stress concentration
2. Referenced Documents
directly under the loading noses or supports, the radius of the
2.1 ASTM Standards:
noses and supports shall be at least 0.25 in. (6.35 mm). See Fig.
C1228 Practice for Preparing Coupons for Flexural and
1 for loading configuration. The arc of the loading noses and
Washout Tests on Glass Fiber Reinforced Concrete
supports, in contact with the specimen, shall be sufficiently
D76/D76M Specification for Tensile Testing Machines for
large to prevent contact of the specimen with the sides of the
Textiles
noses. Neoprene pads, approximately ⁄16 in. (1.6 mm) thick,
E4 Practices for Force Calibration and Verification of Test-
may be placed between the loading noses and the test specimen
ing Machines
for uniform load distribution across the width of the specimen.
However, neoprene pads should not be used if deflection
3. Significance and Use
measurements are to be made, as the compression of the
3.1 Flexural properties determined by this test method are
neoprene will distort the measurements.
useful for quality control of glass-fiber reinforced concrete
4.3 Loading Head and Support Apparatus—Loading noses,
supports, and their respective holding devices shall be designed
to allow rotation to occur about axes that lie in horizontal
This test method is under the jurisdiction of ASTM Committee C27 on Precast
planes of the loading apparatus as shown in Fig. 1. This
Concrete Products and is the direct responsibility of Subcommittee C27.40 on Glass
Fiber Reinforced Concrete.
configuration of loading head and support apparatus will
Current edition approved May 1, 2023. Published May 2023. Originally
ensure that forces applied to the specimen will be initially
approved in 1981. Last previous edition approved in 2016 as C947 – 03(2016). DOI:
perpendicular to the surfaces of the specimen and applied
10.1520/C0947-03R23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or without eccentricity.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
4.4 Specimen Depth and Width Measuring Device—A cali-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. per or micrometer or other suitable device that is able to
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C947 − 03 (2023)
8.3 Align the loading noses and supports so that the axes of
the cylindrical surfaces are parallel.
NOTE 1—The parallelism of the loading noses and supports may be
checked by means of a plate containing parallel grooves into which the
loading noses and supports will fit when properly aligned.
8.4 Center the specimen on the supports with equal lengths
of specimen projecting outside of the supports with the long
axis of the specimen perpendicular to the loading noses and
supports.
8.5 Test three specimens with the mold face in tension and
three specimens with the opposite face (or trowelled face) in
tension.
8.6 Set the crosshead speed of the testing machine at 0.05 to
0.20 in./min (1.27 to 5.1 mm/min). Set the chart speed to 75 6
25 times the crosshead speed being used. Set the initial load
measuring range such that the flexural yield strength (F ) load
y
occurs at not less than 30 % of full scale. Apply force at a
constant crosshead speed to specimen failure. Examine the
failure location of the specimen. If failure occurs outside the
FIG. 1 Loading Configuration for Flexural Testing
minor span, discard the specimen and specimen test data.
NOTE 2—The chart speed may be reduced or stopped after the
force-deflection curve reaches its point of deviation fro
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