ASTM C1399-07a
(Test Method)Standard Test Method for Obtaining Average Residual-Strength of Fiber-Reinforced Concrete
Standard Test Method for Obtaining Average Residual-Strength of Fiber-Reinforced Concrete
SIGNIFICANCE AND USE
This test method provides a quantitative measure useful in the evaluation of the performance of fiber–reinforced concrete. It allows for comparative analysis among beams containing different fiber types, including materials, dimension and shape, and different fiber contents. Results can be used to optimize the proportions of fiber–reinforced concrete mixtures, to determine compliance with construction specifications, to evaluate fiber–reinforced concrete which has been in service, and as a tool for research and development of fiber–reinforced concrete (See Note 2).
Note 2—Banthia and Dubey3 compared results using this test method with residual strengths at the same net deflections using a test protocol that is similar to that described in Test Method C 1609/C 1609M on 45 beams with a single fiber configuration at proportions of 0.1, 0.3, and 0.5 % by volume. The results by this test method were on average 6.4 % lower than by the procedure of Test Method C 1609/C 1609M.
Test results are intended to reflect either consistency or differences among variables used in proportioning the fiber–reinforced concrete to be tested, including fiber type (material), fiber size and shape, fiber amount, beam preparation (sawed or molded), and beam conditioning.
In molded beams fiber orientation near molded surfaces will be affected by the process of molding. For tests of fiber-reinforced concrete containing relatively rigid or stiff fibers of length greater than 40 mm (1.5 in.), the use of sawed beams cut from samples with an initial width and depth of at least 3 times the length of the fiber is required to minimize effects of fiber orientation. When sawed beams are employed, and to avoid the effects of fiber orientation, care shall be applied to ensure that the flexural tensile surface of the beam is a sawed surface.
SCOPE
1.1 This test method covers the determination of residual strength of a fiber-reinforced concrete test beam. The average residual strength is computed using specified beam deflections that are obtained from a beam that has been cracked in a standard manner. The test provides data needed to obtain that portion of the load-deflection curve beyond which a significant amount of cracking damage has occurred and it provides a measure of post-cracking strength, as such strength is affected by the use of fiber-reinforcement.
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.
1.2 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: C1399 – 07a
Standard Test Method for
Obtaining Average Residual-Strength of Fiber-Reinforced
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Concrete
This standard is issued under the fixed designation C1399; 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* C1609/C1609M Test Method for Flexural Performance of
Fiber-Reinforced Concrete (Using Beam With Third-Point
1.1 This test method covers the determination of residual
Loading)
strength of a fiber–reinforced concrete test beam. The average
residual strength is computed using specified beam deflections
3. Terminology
that are obtained from a beam that has been cracked in a
3.1 Definitions of Terms Specific to This Standard:
standard manner. The test provides data needed to obtain that
3.1.1 deflection—mid–span deflection of the test beam ob-
portionoftheload–deflectioncurvebeyondwhichasignificant
tained in a manner that excludes deflection caused by the
amount of cracking damage has occurred and it provides a
following: (1) the flexural test apparatus, (2) crushing and
measure of post–cracking strength, as such strength is affected
seating of the beam at support contact points, and (3) torsion of
by the use of fiber–reinforcement.
the beam; sometimes termed net deflection.
1.2 This standard does not purport to address all of the
3.1.2 initial loading curve—the load–deflection curve ob-
safety concerns, if any, associated with its use. It is the
tained by testing an assembly that includes both the test beam
responsibility of the user of this standard to establish appro-
and a specified steel plate (Fig. 1); plotted to a deflection of at
priate safety and health practices and determine the applica-
least 0.25 mm (0.010 in.) (Fig. 3).
bility of regulatory limitations prior to use.
3.1.3 reloading curve—the load–deflection curve obtained
1.3 The values stated in SI units are to be regarded as the
by reloading and retesting the pre-cracked beam, that is, after
standard. The values in parentheses are for information only.
the initial loading but without the steel plate. (Fig. 3)
2. Referenced Documents 3.1.4 reloading deflection—deflection measured during the
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reloading of the cracked beam and with zero deflection
2.1 ASTM Standards:
referenced to the start of the reloading.
C31/C31M Practice for Making and Curing Concrete Test
3.1.5 residual strength—the flexural stress on the cracked
Specimens in the Field
beam section obtained by calculation using loads obtained
C42/C42M Test Method for Obtaining and Testing Drilled
from the reloading curve at specified deflection values (See
Cores and Sawed Beams of Concrete
Note 1).
C78 Test Method for Flexural Strength of Concrete (Using
Simple Beam with Third-Point Loading)
NOTE 1—Residual strength is not a true stress but an engineering stress
C172 Practice for Sampling Freshly Mixed Concrete computed using the flexure formula for linear elastic materials and gross
(uncracked) section properties.
C192/C192M Practice for Making and Curing Concrete
Test Specimens in the Laboratory
3.1.6 average residual strength—the average stress–carry-
C823 Practice for Examination and Sampling of Hardened
ing ability of the cracked beam that is obtained by calculation
Concrete in Constructions
using the residual strength at four specified deflections.
4. Summary of Test Method
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This test method is under the jurisdiction of ASTM Committee C09 on 4.1 Cast or sawed beams of fiber–reinforced concrete are
Concrete and ConcreteAggregates and is the direct responsibility of Subcommittee
cracked using the third–point loading apparatus specified in
C09.42 on Fiber-Reinforced Concrete.
Test Method C78 modified by a steel plate used to assist in
Current edition approved Aug. 1, 2007. Published September 2007. Originally
support of the concrete beam during an initial loading cycle
approved in 1998. Last previous edition approved in 2007 as C1399–07. DOI:
10.1520/C1399-07A.
(Fig. 1). The steel plate is used to help control the rate of
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or
deflection when the beam cracks. After the beam has been
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
cracked in the specified manner, the steel plate is removed and
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. the cracked beam is reloaded to obtain data to plot a reloading
*A Summary of Changes section appears at the end of this standard.
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