ASTM D7705/D7705M-12(2019)
(Test Method)Standard Test Method for Alkali Resistance of Fiber Reinforced Polymer (FRP) Matrix Composite Bars used in Concrete Construction
Standard Test Method for Alkali Resistance of Fiber Reinforced Polymer (FRP) Matrix Composite Bars used in Concrete Construction
SIGNIFICANCE AND USE
5.1 This test method is intended to determine alkaline resistance data for material specifications, research and development, quality assurance, and structural design and analysis. Depending on the procedure and test matrix, the primary test results are the mass change and tensile capacity retention of the test specimen, which are important factors to be considered in the use of FRP reinforcing bars. Procedures A and B are accelerated tests, substituting an alkaline aqueous environment for the presence of concrete porewater. Procedure C can be used to establish the accelerating effect of Procedure B.
5.1.1 Procedure A is appropriate for rapid screening of FRP bars for alkali resistance.
5.1.2 Procedure B is appropriate for characterizing the alkali resistance of FRP bars under sustained mechanical loading in a standard aqueous alkaline environment intended to represent the concrete porewater.
5.1.3 Procedure C is appropriate for characterizing the alkali resistance of FRP bars under sustained mechanical loading in Portland cement concrete.
SCOPE
1.1 This test method covers the procedure for evaluating the alkali resistance of FRP bars used as reinforcing bars in concrete. Alkali resistance is measured by subjecting the FRP bars to an aqueous alkali environment, with or without sustained tensile stress, and then testing them to failure in tension according to Test Method D7205/D7205M. This standard presents three procedures conducted at a moderately elevated temperature of 60 ºC (140 ºF), each defining different loading conditions. The test method is also appropriate for use with linear segments of FRP reinforcements cut from two- or three-dimensional reinforcing grid.
1.2 The values stated in either inch-pound units or SI units shall be regarded separately as the standard. The inch-pound units are shown in the parentheses. The values stated in each system are not exact equivalents; therefore each system shall be used independently of each other. Combining values from the two systems may result in non-conformance.
1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 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.
General Information
Relations
Standards Content (Sample)
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: D7705/D7705M − 12 (Reapproved 2019)
Standard Test Method for
Alkali Resistance of Fiber Reinforced Polymer (FRP) Matrix
Composite Bars used in Concrete Construction
This standard is issued under the fixed designation D7705/D7705M; 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 A615/A615M SpecificationforDeformedandPlainCarbon-
Steel Bars for Concrete Reinforcement
1.1 This test method covers the procedure for evaluating the
C192/C192M Practice for Making and Curing Concrete Test
alkali resistance of FRP bars used as reinforcing bars in
Specimens in the Laboratory
concrete. Alkali resistance is measured by subjecting the FRP
C496/C496M Test Method for Splitting Tensile Strength of
bars to an aqueous alkali environment, with or without sus-
Cylindrical Concrete Specimens
tained tensile stress, and then testing them to failure in tension
C511 Specification for Mixing Rooms, Moist Cabinets,
according to Test Method D7205/D7205M. This standard
presents three procedures conducted at a moderately elevated Moist Rooms, and Water Storage Tanks Used in the
temperature of 60 ºC (140 ºF), each defining different loading Testing of Hydraulic Cements and Concretes
conditions. The test method is also appropriate for use with
C1260 Test Method for Potential Alkali Reactivity of Ag-
linear segments of FRP reinforcements cut from two- or
gregates (Mortar-Bar Method)
three-dimensional reinforcing grid.
C1293 Test Method for Determination of Length Change of
Concrete Due to Alkali-Silica Reaction
1.2 The values stated in either inch-pound units or SI units
D618 Practice for Conditioning Plastics for Testing
shall be regarded separately as the standard. The inch-pound
D883 Terminology Relating to Plastics
units are shown in the parentheses. The values stated in each
D3878 Terminology for Composite Materials
system are not exact equivalents; therefore each system shall
D7205/D7205M Test Method for Tensile Properties of Fiber
be used independently of each other. Combining values from
the two systems may result in non-conformance. Reinforced Polymer Matrix Composite Bars
E4 Practices for Force Verification of Testing Machines
1.3 This standard does not purport to address all of the
E6 Terminology Relating to Methods of Mechanical Testing
safety concerns, if any, associated with its use. It is the
E70 Test Method for pH of Aqueous Solutions With the
responsibility of the user of this standard to establish appro-
Glass Electrode
priate safety, health, and environmental practices and deter-
E456 Terminology Relating to Quality and Statistics
mine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accor-
dance with internationally recognized principles on standard- 3. Terminology
ization established in the Decision on Principles for the
3.1 Terminology in D3878 defines terms relating to high-
Development of International Standards, Guides and Recom-
modulus fibers and their composites. Terminology in D883
mendations issued by the World Trade Organization Technical
defines terms relating to plastics. Terminology in E6 defines
Barriers to Trade (TBT) Committee.
terms relating to mechanical testing. Terminology in E456
defines terms relating to statistics and the selection of sample
2. Referenced Documents
sizes. In the event of a conflict between terms, Terminology in
2.1 ASTM Standards:
D3878 shall have precedence over the other terminology
standards.
This test method is under the jurisdiction of ASTM Committee D30 on
3.2 Definitions of Terms Specific to This Standard:
Composite Materials and is the direct responsibility of Subcommittee D30.10 on
3.2.1 bar, n—a linear element, with a substantially round
Composites for Civil Structures.
Current edition approved Feb. 1, 2019. Published February 2019. Originally
cross-section, often with surface undulations or a coating of
approved in 2012. Last previous edition approved in 2012 as D7705/D7705M – 12.
particles that promote mechanical interlock with concrete.
DOI: 10.1520/D7705_D7705M-12R19.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3.2.2 nominal cross-sectional area, n—a measure of cross-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
sectional area of a bar, determined over at least one represen-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. tative length, used to calculate stress.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7705/D7705M − 12 (2019)
3.2.3 representative length, n—the minimum length of a bar removed from the alkaline solution and tested in tension. The
that contains a repeating geometric pattern that, placed end-to- test parameters are the sustained force level, the pH value, and
end, reproduces the geometric pattern of a continuous bar the immersion time.
(usually used in reference to bars having surface undulations 4.1.3 Procedure C is designed to test the alkali resistance of
for enhancing interlock with concrete). FRP specimens embedded in moist concrete under sustained
tensile force. Four sets of specimens are embedded in moist
3.2.4 standard cross-sectional area, n—the cross-sectional
concrete and held under a sustained tensile force. Each set of
area of a standard numbered steel concrete reinforcing bar as
specimens is conditioned for a different period of time: 1, 2, 3,
given in Specification A615/A615M, Table 1.
or 6 months.After each of the required conditioning times, one
3.2.5 surface undulation, n—variation in the area,
set of specimens are removed from the conditioning environ-
orientation, or shape of cross-section of a bar along its length,
ment and tested in tension. The test parameters are the
intended to enhance mechanical interlock between a bar and
sustained force level, the pH value, and the embedment time.
concrete, made by any of a number of processes such as, for
4.2 The level of sustained loading (for Procedures B and C)
example, indentation, addition of extra materials, and twisting.
is not specified as part of the test method. If service load
3.2.6 traveler, n—a short bar segment, subject to the same
conditions are not known, the sustained tensile stress in
environmental conditions as the tension specimens, used for
glass-fiber FRP bars shall be set to induce an initial tensile
mass change measurements in Procedure A.
strain equal to 2000 microstrain. The level of sustained stress
shall be reported.
3.3 Symbols:
3.3.1 F —tensile capacity before conditioning (but after
tu0
5. Significance and Use
pre-conditioning), a baseline established according to Test
5.1 This test method is intended to determine alkaline
Method D7205/D7205M.
resistance data for material specifications, research and
3.3.2 F —tensile capacity after conditioning and post-
tu1
development, quality assurance, and structural design and
conditioning, established according to Test Method D7205/
analysis. Depending on the procedure and test matrix, the
D7205M.
primary test results are the mass change and tensile capacity
3.3.3 R —tensile capacity retention, compared to the base-
et
retention of the test specimen, which are important factors to
line measurement measured according to Test Method D7205/
be considered in the use of FRPreinforcing bars. ProceduresA
D7205M, expressed as a percentage.
and B are accelerated tests, substituting an alkaline aqueous
environment for the presence of concrete porewater. Procedure
3.3.4 W —mass of traveler specimen before conditioning.
C can be used to establish the accelerating effect of Procedure
3.3.5 W —mass of traveler specimen after post-
1A
B.
conditioning.
5.1.1 ProcedureAis appropriate for rapid screening of FRP
3.3.6 W —mass of traveler specimen before post-
1B bars for alkali resistance.
conditioning.
5.1.2 Procedure B is appropriate for characterizing the
alkali resistance of FRP bars under sustained mechanical
4. Summary of Test Method
loadinginastandardaqueousalkalineenvironmentintendedto
represent the concrete porewater.
4.1 This test method provides standardized requirement for
5.1.3 Procedure C is appropriate for characterizing the
determining the alkali resistance of FRP bars under laboratory
alkali resistance of FRP bars under sustained mechanical
conditions. The principal variables used in the laboratory tests
loading in Portland cement concrete.
are the nature and concentration of the alkaline solution, and
the sustained force level. Three procedures are available
6. Interferences
depending on the goals of the test.
6.1 Test Conditions—Hygro-thermal degradation of FRP
4.1.1 ProcedureAis designed to test the alkali resistance of
composite materials is highly dependent upon environmental
FRP specimens with no tensile force applied. Four sets of
conditions such as, for example, temperature, humidity, and
specimens are immersed in an alkaline solution without tensile
chemical agents. The FRP bars shall be conditioned under
force. Each set of specimens is immersed for a different period
tightly controlled and monitored conditions. For bars condi-
of time: 1, 2, 3, or 6 months. After each of the required
tioned in aqueous solutions, the conditioning solutions may
conditioning times, one set of specimens is removed from the
change over time due to evaporation. The quantity and pH of
alkaline solution and tested in tension. The test control param-
the solution shall be maintained by the addition of hydroxides
eters are the pH value and temperature of the alkaline solution
and tap water as necessary to maintain the required pH level.
and the immersion time. ProcedureAalso determines the mass
uptake (or loss) of the specimens using travellers.
6.2 Additional interferences associated with execution of
the tension testing can be found in Test Method D7205/
4.1.2 Procedure B is designed to test the alkali resistance of
FRP specimens with sustained tensile force. Four sets of D7205M.
specimens are immersed in an alkaline solution under a
7. Apparatus
sustained tensile force. Each set of specimens is conditioned
for a different period of time: 1, 2, 3, or 6 months. After each 7.1 Balance—For Procedure A, an analytical balance with
of the required conditioning times, one set of specimens is an accuracy of 0.1 mg for traveler specimens weighing 50 g or
D7705/D7705M − 12 (2019)
less, and with an accuracy of 1 mg for traveler specimens 9. Calibration
weighing more than 50 g.
9.1 The accuracy of all measuring equipment shall have
certified calibrations that are current at the time of use of the
7.2 For Procedures B and C, a sustained loading apparatus
capable of applying and maintaining a force on the specimen equipment.
within 61 % of the desired sustained force.
10. Conditioning
7.3 TestApparatus—Atensiontestingapparatuswithaforce
10.1 Pre-Conditioning for All Specimens—All specimens,
capacity in excess of the tensile capacity of the specimen and
including those used for baseline measurements and traveler
calibrated according to Practices E4.
specimens for weight-change measurements shall be pre-
7.4 Anchors—Anchors shall be in accordance with Test
conditioned in accordance with Procedure B of Practice D618.
Method D7205/D7205M.
For ProcedureA, traveler specimens should be weighed before
pre-conditioning.
7.5 For ProceduresAand B, an apparatus for measuring pH
of aqueous solutions in accordance with Test Method E70.
10.2 Specimens for Procedure A shall be immersed in the
alkaline solution at 60 6 3 °C (140 6 5 °F) for exposure times
7.6 Environmental Test Chamber—An environmental test
of 1, 2, 3, or 6 months, unless longer exposure periods are
chamber capable of maintaining the required temperature to
specified. After the allotted times, the specimens shall be
within 63°C[65 °F]. In addition, the chamber may have to
removed from the alkaline solution and thoroughly washed in
be capable of maintaining environmental conditions such as
tap water.
fluid exposure during the test.
10.3 Specimens for Procedure B shall be installed with
NOTE 1—For Procedures A and B, it is acceptable to substitute a
anchoringdevicesatbothendsinaccordancewithTestMethod
temperature-controlled bath for the environmental chamber.
D7205/D7205M,AppendixA.The test section of the specimen
shall be immersed in the alkaline solution inside an environ-
8. Test Specimens
mental cabinet or container holding the alkaline solutions and
8.1 FRP bar specimens shall be representative of the lot or
having a constant temperature of 60 6 3 °C (140 6 5 °F). The
batch being tested. In general, test specimens shall not be
specimen shall be held in a loading fixture, subjecting the bar
subjected to any processing beyond manufacturing. For grid-
to a constant tensile sustained force for exposure times of 1, 2,
type FRP bars, linear test specimens may be prepared by
3, or 6 months, unless longer exposure periods are specified.
cutting away extraneous material in such a way as not to affect
After the allotted times, the specimens shall be unloaded and
the performance of the tested part.
removed from the alkaline solution.
8.2 During the sampling and preparation of test specimens,
10.4 Specimens for Procedure C shall be conditioned by
all deformation, heating, outdoor exposure to ultraviolet light,
embedding the test section of the specimens in moist concrete
and other conditions possibly causing changes to material
cylinders as shown in Fig. 1. The cylinders should have a
properties of the specimen shall be avoided.
diameterofatleast150mm(6in.)andbeofsufficientdiameter
8.3 The length of the specimens shall be in accordance with
to provide at least 62 mm (2.5 in.) of clear cover from the
Test Method D7205/D7205M, Table A1.1.
surface of the concrete to the surface of the bar. The length of
the cylinder shall be at least 200 mm (8 in.) but should not be
8.4 The cross-sectional area of the specimen shall be deter-
less than 15 times the diameter of the FRPbar. For FRPbars in
mined in accordance with either of the two methods described
twisted strand form, the cylinder length should also be greater
in Test Method D7205/D7205M: nominal area or standard
than the strand pitch.
area.
10.4.1 Specimens shall be cured for 28 days in tap water at
8.5 The number of test specimens in each se
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.