ASTM A981-97(2007)
(Test Method)Standard Test Method for Evaluating Bond Strength for 15.2 mm (0.6 in.) Diameter Prestressing Steel Strand, Grade 270, Uncoated, Used in Prestressed Ground Anchors
Standard Test Method for Evaluating Bond Strength for 15.2 mm (0.6 in.) Diameter Prestressing Steel Strand, Grade 270, Uncoated, Used in Prestressed Ground Anchors
ABSTRACT
This test method deals with the standard procedures for establishing the relative bond strength of Grade 270 prestressing steel strands of specified diameter in cement grout as used in prestressed ground anchors for evaluating the effects of manufacturing practices on bond strength. The bond strength values obtained shall not be used to design the bond strength of ground anchors that depend on field conditions. This test method is not intended to be used as a bond test for pretensioned concrete applications. The test specimen shall be cut from standard production coils and shall not be wiped or cleaned. Pull test shall be made in accordance with the method.
SCOPE
1.1 This test method describes procedures to establish the relative bond strength of 15.2 mm (0.6 in.) diameter, Grade 270 prestressing steel strand in cement grout as used in prestressed ground anchors for the purpose of evaluating the effects of manufacturing practices on bond strength.
1.2 The bond strength values obtained shall not be used to design the bond length of ground anchors that depend on field conditions.
1.3 This test method is not intended to be used as a bond test for pretensioned concrete applications.
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
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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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:A981–97 (Reapproved 2007)
Standard Test Method for
Evaluating Bond Strength for 15.2 mm (0.6 in.) Diameter
Prestressing Steel Strand, Grade 270, Uncoated, Used in
Prestressed Ground Anchors
This standard is issued under the fixed designation A981; 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 3. Terminology
1.1 This test method describes procedures to establish the 3.1 Definitions of Terms Specific to This Standard:
relativebondstrengthof15.2mm(0.6in.)diameter,Grade270 3.1.1 bond strength—maximum measured load in a pull test
prestressing steel strand in cement grout as used in prestressed on a 15.2 mm (0.6 in.) diameter prestressing steel strand
ground anchors for the purpose of evaluating the effects of embedded in cement grout.
manufacturing practices on bond strength. 3.1.2 bonded length—the length of the test strand that is in
1.2 The bond strength values obtained shall not be used to contact with the cement grout.
design the bond length of ground anchors that depend on field
4. Apparatus
conditions.
1.3 Thistestmethodisnotintendedtobeusedasabondtest 4.1 Equipment—A suitable tensile test machine or load
frame shall be used. The loading system shall be calibrated in
for pretensioned concrete applications.
1.4 The values stated in SI units are to be regarded as the accordance with Practices E4. The test system shall have
sufficient capacity to prevent yielding of its various compo-
standard. The values given in parentheses are for information
only. nents and shall ensure that the applied tensile load remains
parallel to the axis of the prestressing steel strand during
1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the testing.
4.2 Strand Displacement Measurements—Displacements of
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- the free end of the prestressing steel strand shall be measured
bility of regulatory limitations prior to use. with respect to the loaded surface of the test specimen using
suitable measurement devices. Dial gages having the smallest
2. Referenced Documents
division of not more than 25 µm (0.001 in.) or linear variable
2.1 ASTM Standards: differential transformers (LVDTs) with equal or superior accu-
A416/A416M Specification for Steel Strand, Uncoated racy are examples of satisfactory devices.
Seven-Wire for Prestressed Concrete
5. Test Specimen
C150 Specification for Portland Cement
C511 Specification for Mixing Rooms, Moist Cabinets, 5.1 Prestressing Steel Strand—shall be 15.2 mm (0.6 in.)
diameter, Grade 270 and comply with Specification A416/
Moist Rooms, and Water Storage Tanks Used in the
Testing of Hydraulic Cements and Concretes A416M and shall be cut from standard production coils. The
surface of the test samples shall not be wiped or cleaned in
C1019 Test Method for Sampling and Testing Grout
E4 Practices for Force Verification of Testing Machines order to preserve their original condition. Minimum recom-
mended sample length is 750 mm (30 in.).
5.2 Strand Bond Test Specimen—The test specimen shall
This test method is under the jurisdiction of ASTM Committee A01 on Steel, consist of the prestressing steel strand embedded in cement
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee
groutandcenteredinsideasteelpipe,125mm(5in.)O.D.with
A01.05 on Steel Reinforcement.
a 3 mm (0.125 in.) wall, 450 mm (18 in.) long with a 150 by
Current edition approved Sept. 1, 2007. Published September 2007. Originally
150 by 6 mm (6 by 6 by 0.25 in.) base plate welded, or
approve din 1997. Last previous edition approved in 2002 as A981 – 97 (2002).
DOI: 10.1520/A0981-97R07.
otherwise leakproof connected to one end of the steel pipe.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Other mold designs, including reusable molds, shall be per-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
missible, provided that the dimensions and confinement in
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. regard to circumferential stress provided for the grout body are
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A981–97 (2007)
the same.Ahole in the base plate shall allow the strand to pass cation C511ata23 6 1.7°C (74 6 3°F) temperature and
through. A50 mm (2 in.) long debonding tube shall be minimum 95 percent relative humidity until the grout strength,
positioned on the strand above the base plate and the strand as determined according to Test Method C1019 on at least two
shall protrude at least 50 6 10 mm (2 6 0.5 in.) from the top 50 by 50 by 50 mm (2 by 2 by 2 in.) test cubes, has reached a
of the grouted steel tube. A typical test specimen is illustrated compressive strength of
...
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