ASTM A981-97

NOTICE: This standard has either been superseded and replaced by a new version or
withdrawn. Contact ASTM International (www.astm.org) for the latest information.
Designation: A 981 – 97
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Evaluating Bond Strength for 15.2 mm (0.6 in.) Diameter
Prestressing Steel Strand, Grade 270, Uncoated, Used in
1
Prestressed Ground Anchors
This standard is issued under the fixed designation A 981; 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.
1. Scope embedded in cement grout.
3.1.2 bonded length—the length of the test strand that is in
1.1 This test method describes procedures to establish the
contact with the cement grout.
relative bond strength of 15.2 mm (0.6 in.) diameter, Grade 270
prestressing steel strand in cement grout as used in prestressed
4. Apparatus
ground anchors for the purpose of evaluating the effects of
4.1 Equipment—A suitable tensile test machine or load
manufacturing practices on bond strength.
frame shall be used. The loading system shall be calibrated in
1.2 The bond strength values obtained shall not be used to
accordance with Practices E 4. The test system shall have
design the bond length of ground anchors that depend on field
sufficient capacity to prevent yielding of its various compo-
conditions.
nents and shall ensure that the applied tensile load remains
1.3 This test method is not intended to be used as a bond test
parallel to the axis of the prestressing steel strand during
for pretensioned concrete applications.
testing.
1.4 The values stated in SI units are to be regarded as the
4.2 Strand Displacement Measurements—Displacements of
standard. The values given in parentheses are for information
the free end of the prestressing steel strand shall be measured
only.
with respect to the loaded surface of the test specimen using
1.5 This standard does not purport to address all of the
suitable measurement devices. Dial gages having the smallest
safety concerns, if any, associated with its use. It is the
division of not more than 25 μm (0.001 in.) or linear variable
responsibility of the user of this standard to establish appro-
differential transformers (LVDTs) with equal or superior accu-
priate safety and health practices and determine the applica-
racy are examples of satisfactory devices.
bility of regulatory limitations prior to use.
5. Test Specimen
2. Referenced Documents
5.1 Prestressing Steel Strand—shall be 15.2 mm (0.6 in.)
2.1 ASTM Standards:
diameter, Grade 270 and comply with Specification A 416 and
A 416 Specification for Steel Strand, Uncoated Seven Wire
2 shall be cut from standard production coils. The surface of the
for Prestressed Concrete
3 test samples shall not be wiped or cleaned in order to preserve
C 150 Specifications for Portland Cement
their original condition. Minimum recommended sample
C 511 Specification for Moist Cabinets, Moist Rooms and
length is 750 mm (30 in.).
Water Storage Tanks Used in the Testing of Hydraulic
3 5.2 Strand Bond Test Specimen—The test specimen shall
Cements and Concrete
4 consist of the prestressing steel strand embedded in cement
C 1019 Test Method for Sampling and Testing Grouts
5 grout and centered inside a steel pipe, 125 mm (5 in.) O.D. with
E 4 Practices for Force Verification of Testing Machines
a 3 mm (0.125 in.) wall, 450 mm (18 in.) long with a 150 by
3. Terminology 150 by 6 mm (6 by 6 by 0.25 in.) base plate welded, or
otherwise leakproof connected to one end of the steel pipe.
3.1 Definitions of Terms Specific to This Standard:
Other mold designs, including reusable molds, shall be per-
3.1.1 bond strength—maximum measured load in a pull test
missible, provided that the dimensions and confinement in
on a 15.2 mm (0.6 in.) diameter prestressing steel strand
regard to circumferential stress provided for the grout body are
the same. A hole in the base plate shall allow the strand to pass
1
This test method is under the jurisdiction of ASTM Committee A-1 on Steel,
through. A 50 mm (2 in.) long debonding tube shall be
Stainless Steel, and Related Alloys and is the direct responsibility of Subcommittee
positioned on the strand above the base plate and the strand
A01.05 on Steel Reinforcement.
shall protrude at least 50 6 10 mm (2 6 0.5 in.) from the top
Current edition approved Nov. 10, 1997. Published September 1998.
2
Annual Book of ASTM Standards, Vol 01.04.
of the grouted steel tube. A typical test specimen is illustrated
3
Annual Book of ASTM Standards, Vol 04.02.
in Fig.1.
4
Annual Book of ASTM Standards, Vol 04.05.
5 5.3 Test Specimen Preparation—The untensioned strand
Annual Book of ASTM Standards, V
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