ACI 440.6M-08
Specification for Carbon and Glass Fiber-Reinforced Polymer Bar Materials for Concrete Reinforcement An ACI Standard
Reported by ACI Committee 440
First Printing July 2008 ®
American Concrete Institute Advancing concrete knowledge
Specification for Carbon and Glass Fiber-Reinforced Polymer Bar Materials for Concrete Reinforcement Copyright by the American Concrete Institute, Farmington Hills, MI. All rights reserved. This material may not be reproduced or copied, in whole or part, in any printed, mechanical, electronic, film, or other distribution and storage media, without the written consent of ACI. The technical committees responsible for ACI committee reports and standards strive to avoid ambiguities, omissions, and errors in these documents. In spite of these efforts, the users of ACI documents occasionally find information or requirements that may be subject to more than one interpretation or may be incomplete or incorrect. Users who have suggestions for the improvement of ACI documents are requested to contact ACI. Proper use of this document includes periodically checking for errata at www.concrete.org/committees/errata.asp for the most up-to-date revisions. ACI committee documents are intended for the use of individuals who are competent to evaluate the significance and limitations of its content and recommendations and who will accept responsibility for the application of the material it contains. Individuals who use this publication in any way assume all risk and accept total responsibility for the application and use of this information. All information in this publication is provided “as is” without warranty of any kind, either express or implied, including but not limited to, the implied warranties of merchantability, fitness for a particular purpose or non-infringement. ACI and its members disclaim liability for damages of any kind, including any special, indirect, incidental, or consequential damages, including without limitation, lost revenues or lost profits, which may result from the use of this publication. It is the responsibility of the user of this document to establish health and safety practices appropriate to the specific circumstances involved with its use. ACI does not make any representations with regard to health and safety issues and the use of this document. The user must determine the applicability of all regulatory limitations before applying the document and must comply with all applicable laws and regulations, including but not limited to, United States Occupational Safety and Health Administration (OSHA) health and safety standards. Order information: ACI documents are available in print, by download, on CD-ROM, through electronic subscription, or reprint and may be obtained by contacting ACI. Most ACI standards and committee reports are gathered together in the annually revised Concrete Practice (MCP). American Concrete Institute 38800 Country Club Drive Farmington Hills, MI 48331 U.S.A. Phone: 248-848-3700 Fax: 248-848-3701
www.concrete.org ISBN 978-0-87031-290-8
ACI Manual of
ACI 440.6M-08
Specification for Carbon and Glass Fiber-Reinforced Polymer Bar Materials for Concrete Reinforcement An ACI Standard
Reported by ACI Committee 440 John P. Busel Chair
Carol K. Shield * Secretary
Russell Gentry
James G. Korff
Andrea Prota
Janos Gergely
Michael W. Lee
Hayder A. Rasheed
Lawrence C. Bank
William J. Gold
Maria Lopez de Murphy
Abdeldjelil Belarbi
Nabil F. Grace
Ibrahim M. Mahfouz
Brahim Benmokrane
Mark F. Green
Orange S. Marshall
Rajan Sen
Luke A. Bisby
Zareh B. Gregorian
Amir Mirmiran
Khaled A. Soudki
Gregg J. Blaszak
Doug D. Gremel*
Ayman S. Mosallam
Samuel A. Steere III*
Timothy E. Bradberry*
Shawn P. Gross
John J. Myers
Gamil S. Tadros
Tarek Alkhrdaji Charles E. Bakis *
Gordon L. Brown Jr.
H. R. (Trey) Hamilton III
Antonio Nanni
†
Sami H. Rizkalla Morris Schupack
Jay A. Thomas
Vicki L. Brown
Issam E. Harik
Kenneth Neale
Houssam A. Toutanji
Raafat El-Hacha
Kent A. Harries
John P. Newhook
J. Gustavo Tumialan
*
Ayman M. Okeil
Milan Vatovec
Amir Z. Fam
Bohdan N. Horeczko
Carlos E. Ospina*
Stephanie L. Walkup
Edward R. Fyfe
Vistasp M. Karbhari
Max L. Porter
David White
Garth J. Fallis
*
Mark P. Henderson
*
Contributing authors. Task group Chair. The committee also thanks Nick Carino, Bernard Drouin, Jack Lesko, and Renato Parretti for their contributions. †
This Material Specification covers provisions governing testing, evaluation, and acceptance of carbon and glass fiber-reinforced polymer (FRP) bars used as reinforcement for concrete.
Section 8—Mechanical properties, p. 440.6-4
Keywords : carbon fiber; concrete; concrete construction; FRP reinforced concrete; fiber-reinforced polymer reinforcement; glass fiber; specification.
Section 10—Other requirements, p. 440.6-5
CONTENTS Section 1—Scope, p. 440.6-2
Section 9—Durability properties, p. 440.6-4
Section 11—Sampling, p. 440.6-5 Section 12—Rejection, p. 440.6-5
Section 2—Referenced documents, p. 440.6-2
Section 13—Product certification, p. 440.6-5
Section 3—Terminology, p. 440.6-2
Section 14—Markings, p. 440.6-6
Section 4—Classification, p. 440.6-2 Section 5—Ordering information, p. 440.6-3 Section 6—Materials and manufacture, p. 440.6-3 Sections 7—Physical properties, p. 440.6-3
ACI 440.6M-08 was adopted April 30, 2008, and published June 2008. Copyright © 2008, American Concrete Institute. All rights reserved including rights of reproduction and use in any form or by any means, including the making of copies by any photo process, or by electronic or mechanical device, printed, written, or oral, or recording for sound or visual reproduction or for use in any knowledge or retri eval system or device, unless permission in writing is obtained from the copyright proprietors.
440.6M-1
440.6M-2
ACI STANDARD
SECTION 1—SCOPE 1.1 This specification describes permitted constituent materials, limits on constituent volumes, and minimum performance requirements for carbon and glass fiber-reinforced polymer (FRP) bars to be used as reinforcement for nonprestressed concrete. 1.2 Only carbon and glass FRP bars are covered by this specification. 1.3 FRP bars made of more than one fiber type (hybrid FRP) are not covered by this specification. 1.4 Pultruded FRP bars with no external surface enhancement (that is, plain or smooth bars) to facilitate bond with concrete are not covered by this specification. Similarly, hollow FRP bars are not considered due to lack of documented performance as reinforcement for concrete. 1.5 Plain FRP bars used as dowels (that is, devices that transfer shear across concrete joints) where the intended function requires slip of the dowel are not covered by this specification. 1.6 This specification does not cover premanufactured grids and gratings made with FRP materials. FRP mats resulting from assembly of deformed FRP bars, however, are covered by this document. 1.7 This specification does not cover FRP bars when used for external and near-surface-mounted strengthening applications. 1.8 The text of this specification references notes and footnotes that provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the specification.
SECTION 2—REFERENCED DOCUMENTS 2.1—ASTM standards A615/A615M-08a Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement C904-01(2006) Standard Terminology Relating to Chemical-Resistant Nonmetallic Materials D570-98(2005) Standard Test Method for Water Absorption of Plastics D2584-02 Standard Test Method for Ignition Loss of Cured Reinforced Resins D3171-06 Standard Test Methods for Constituent Content of Composite Materials D4475-02(2008) Standard Test Method for Apparent Horizontal Shear Strength of Pultruded Reinforced Plastic Rods by the ShortBeam Method D5117-03 Standard Test Method for Dye Penetr ation of Solid Fiberglass Reinforced Pultruded Stock D5229/ Standard Test Method for Moisture D5229M-92(2004) Absorption Properties and Equilibrium Conditioning of Polymer Matrix Composite Materials D7205/ Standard Test Method for Tensile D7205M-06 Properties of Fiber Reinforced Polymer Matrix Composite Bars
E1356-03
E1640-04
Standard Test Method for Assignment of the Glass Transition Temperatures by Differential Scanning Calorimetry Standard Test Method for Assignment of the Glass Transition Temperature by Dynamic Mechanical Analysis
2.2—ACI report
The following test methods from ACI 440.3R, * “Guide Test Methods for Fiber-Reinforced Polymers (FRPs) for Reinforcing or Strengthening Concrete Structures,” are referenced. Because these test methods are not written in mandatory language, purchaser and manufacturer shall agree on the protocols to be used. B.3 Test method for bond strength of FRP bars by pullout testing B.4 Test method for transverse shear strength of FRP bars B.5 Test method for strength of FRP bent bars and stirrups at bend locations B.6 Accelerated test method for alkali resistance of FRP bars B.12 Test method for determining the effect of corner radius on tensile strength of FRP bars
SECTION 3—TERMINOLOGY 3.1— Definitions
For definitions of terms used in this specification, refer to ASTM C904.
3.2—Definitions of terms specific to this specification commercial-grade material—a material formulated for and used in industrial (not consumer) applications. production lot—any lot of FRP bar produced from start to finish with the same constituent materials used in the same proportions without changing any production parameter, such as cure temperature or line speed. property, guaranteed—a characteristic value provided by the manufacturer no greater than the mean minus three standard deviations of at least the required number of samples tested according to a specified test method. This definition is applicable to tensile strength, shear strength (perpendicular to the bar), bond strength, and strength of bent bars. property, nominal—a value provided by the manufacturer no greater than the mean of at least the required number of samples tested according to a specified method. This definition is applicable to tensile elastic modulus, moisture absorption, and resistance to alkaline environment.
SECTION 4—CLASSIFICATION 4.1 FRP bars shall be classified according to fiber composition with the first letter of the acronym designating fiber type as follows: • CFRP: carbon fiber-reinforced polymer bar • GFRP: glass fiber-reinforced polymer bar
* ACI Committee 440, 2004, “Guide Test Methods for Fiber-Reinforced Polymers (FRPs) for Reinforcing or Strengthening Concrete Structures (ACI 440.3R-04),” American Concrete Institute, Farmington Hills, MI, 40 pp.
SPECIFICATION FOR CARBON AND GLASS FRP BAR MATERIALS FOR CONCRETE REINFORCEMENT
SECTION 5—ORDERING INFORMATION 5.1 The purchaser shall specify the following: • The classification of bar (see Note 1); • The method for creating the deformed bar surface; • The bar size; • The bar length; and • For bent bars, the shape of the bend, the radius of the bend, and the length of the legs. (Note 1—The bar classification—CFRP or GFRP—corresponds to given constituents and the minimum mechanical properties in this specification.)
SECTION 6—MATERIALS AND MANUFACTURE 6.1—Fibers Fibers shall be in the form of unidirectional rovings (glass fibers) or unidirectional tows (carbon fibers) of given size and mass (see Note 2). Fiber sizings and coupling agents shall be compatible with the resin system used to impregnate them. (Note 2—The fiber type and fiber amount determine the physical and mechanical properties of the FRP bar.)
440.6M-3
Table 7.1—Size designation of FRP round bars Bar size designation
Nominal diameter, mm
Nominal area, mm2
6
6.4
32
10
9.5
71
13
12.7
129
16
15.9
199
19
19.1
284
22
22.2
387
25
25.4
510
29
28.7
645
32
32.3
819
SECTION 7—PHYSICAL PROPERTIES 7.1—Fiber content The fiber content shall be measured by ASTM D3171 or D2584. When ASTM D3171 is used, fiber content shall not be less than 55% by volume. When ASTM D2584 is used, fiber content shall not be less than the fraction by mass corresponding to 55% by volume. The manufacturer shall report the fiber content of the end product by volume or by mass in accordance with the method used.
6.2—Matrix resins 6.2.1 Vinylester and epoxy resin systems are permitted provided the finished product meets the physical and durability requirements of this specification. Blending of vinylester and epoxy resins is permitted. 6.2.2 The base polymer in the resin system shall not contain any polyester. 6.2.3 Styrene is permitted to be added to the polymer resin during processing. Added styrene shall be less than 10% by mass of the polymer resin. The amount of styrene, as a mass percentage of the polymer resin, added during processing shall be reported. 6.2.4 Constituent content of resin shall be determined by ASTM D3171.
6.3—Fillers and additives 6.3.1 Only commercial-grade inorganic fillers such as kaolin clay, calcium carbonate, and alumina trihydrate are permitted, and shall not exceed 20% by mass of the polymer resin constituent. 6.3.2 Only commercial-grade additives and process aids, such as release agents, low-profile shrink additives, initiators, promoters, hardeners, catalysts, pigments, fire retardants, and ultraviolet inhibitors are permitted and depend on the processing method. Shrink additives, if used, shall be less than 10% by mass of the polymer resin. 6.3.3 Only commercial-grade inorganic or organic nonwoven surfacing mats or veils are permitted.
6.4—Manufacturing process 6.4.1 The manufacturer shall produce FRP bars using variations of the pultrusion process. 6.4.2 Process or material modifications are not permitted during the production of a single lot. 6.4.3 The manufacturer shall document the process used and report the date of production and production lot size.
7.2—Glass transition temperature The glass transition temperature T g of the resin shall not be less than 100 °C (see Note 3). The glass transition temperature shall be measured on a coupon cut from the as-produced bar using either the differential scanning calorimetry (DSC) method in ASTM E1356 or the dynamic mechanical analysis (DMA) method in ASTM E1640. When using the DSC method, test results for both the first scan (according to ASTM E1356) and the second scan shall be reported. (Note 3—This temperature does not represent the maximum permitted service temperature, and is intended for purchaser’s quality assurance only. ACI 440.1R * does not currently designate maximum service temperatures of FRP bars. Individual manufacturers should be consulted to determine the appropriate maximum service temperature for each product.)
7.3— Bar sizes 7.3.1 Only FRP bars of solid round or elliptical crosssection shape are allowed. 7.3.2 The size of FRP bars shall be consistent with standard sizes for steel reinforcing bars given in ASTM A615/A615M and as listed in Table 7.1. 7.3.3 The calculated diameter of an FRP bar is equivalent to that of a smooth round bar having the same area as the FRP bar measured by ASTM D7205/D7205M. 7.3.4 When the FRP bar is of elliptical shape, the minimum and maximum outside dimensions of the bar cross section shall be provided in addition to the calculated diameter. The calculated diameter of elliptical FRP bars is equivalent to that of a solid round bar having the same cross-sectional area as determined according to ASTM D7205/D7205M.
*ACI Committee 440, 2006, “Guide for the Design and Construction of Structural Concrete Reinforced with FRP Bars (ACI 440.1R-06),” American Concrete Institute, Farmington Hills, MI, 44 pp.
440.6M-4
ACI STANDARD
7.3.5 The nominal diameter of an FRP bar to be used for designation and design shall be equal to the calculated diameter. When the calculated diameter does not correspond to one of the nominal values given in Table 7.1, the next immediately smaller nominal diameter given in such table shall be used.
SECTION 8—MECHANICAL PROPERTIES 8.1—Tensile strength The tensile strength shall be determined for two purposes: 1) overall product certification (that is, guaranteed value) from multiple production lots; and 2) manufacturer’s quality control and purchaser’s quality assurance for each production lot. 8.1.1 The guaranteed tensile strength for product certification shall be measured according to ASTM D7205/D7205M based on nominal dimensions and at a frequency and number of specimens, as indicated in Section 11. Minimum guaranteed tensile strength values are listed in Table 8.1. The manufacturer shall report the individual test results. 8.1.2 The tensile strength of a production lot shall be measured for the purchaser’s quality assurance according to ASTM D7205/D7205M at a frequency and number of specimens as indicated in Section 11. The strength of each specimen shall be reported and be not less than the guaranteed strength reported by the manufacturer. If strength is less than the guaranteed strength, the production lot shall be rejected.
8.2—Tensile modulus of elasticity The tensile modulus of elasticity shall be determined for the purpose of product certification (that is, nominal value). The nominal tensile modulus of elasticity of GFR P bars shall be at least 39.3 GPa regardless of bar size or geometry. The tensile modulus of elasticity of CFRP bars shall be at least 124 GPa regardless of bar size or geometry. The tensile modulus of elasticity is derived from specimens tested in accordance with ASTM D7205/D7205M at a frequency and number of specimens as indicated in Section 11. The manufacturer shall report the individual test results.
8.3—Shear strength (perpendicular to bar) The transverse shear strength shall be determined for the purpose of product certification (that is, guaranteed value). The guaranteed transverse shear strength of FRP bars shall be at least 124 MPa as determined by a test method submitted by the manufacturer for acceptance by the purchaser (see Note 4), at a frequency and number of specimens as indicated in Section 11. The manufacturer shall report the individual test results. (Note 4—ACI 440.3R, Test Method B.4, may be considered by the manufacturer for this purpose.)
8.4—Ultimate tensile strain The ultimate tensile strain shall be calculated for the purpose of product certification (that is, nominal value). The nominal ultimate tensile strain shall be calculated by dividing the guaranteed tensile strength by the nominal elastic modulus (see Note 5). The nominal ultimate tensile strain of CFRP and GFRP bars obtained by this procedure shall be at least 0.5 and 1.2%, respectively.
Table 8.1—Minimum guaranteed tensile strength for FRP bars Minimum guaranteed tensile strength Bar size designation
GFRP, MPa
CFRP, MPa
6
760
1450
10
760
1310
13
690
1170
16
655
1100
19
620
1100
22
586
N/A
25
550
N/A
29
517
N/A
32
480
N/A
Note: N/A indicates that CFRP bars of these sizes are currently not available.
(Note 5—The calculation method is based on the assumption that the stress-strain behavior is linear elastic [straight line]).
8.5—Bond strength The bond strength shall be determined for the purpose of product certification (that is, guaranteed value) for each bar size. The guaranteed bond strength of FRP bars shall be at least 9.6 MPa as determined by a test method submitted by the manufacturer for acceptance by the purchaser (see Note 6), at a frequency and number of specimens as indicated in Section 11. The manufacturer shall report the individual test results and the method used for casting the test specimens. (Note 6—ACI 440.3R, Test Method B.3, may be considered by the manufacturer for this purpose. Such method is intended to determine the relative bond behavior for material specifications, but is not intended for design purposes. Two methods for casting the test specimens are provided in Test Method B.3.).
SECTION 9—DURABILITY PROPERTIES 9.1—Moisture absorption Moisture absorption tests shall be determined for the purpose of product certification (that is, nominal value) in accordance with ASTM D570, Section 7.4, or D5229/ D5229M, Procedure B, using a water temperature of 50 °C at a frequency and number of specimens as indicated in Section 11. The individual moisture absorption test results shall be reported, and their average shall be less than 1.0%.
9.2—Resistance to alkaline environment Resistance to alkaline environment tests shall be determined for the purpose of product certification (that is, nominal value) in accordance with a test method submitted by the manufacturer for acceptance by the purchaser (see Note 7), at a frequency and number of specimens as indicated in Section 11. The manufacturer shall report the individual test results and the test method. Minimum strength retention values have not yet been established. (Note 7—ACI 440.3R, Test Method B.6, may be considered by the manufacturer for this purpose.)
SPECIFICATION FOR CARBON AND GLASS FRP BAR MATERIALS FOR CONCRETE REINFORCEMENT
9.3—Longitudinal wicking Longitudinal wicking shall be determined for the purposes of the purchaser’s quality assurance. Five consecutive 25 mm long segments cut from an FRP bar shall be tested in accordance with ASTM D5117 at a frequency as indicated in Section 11. No continuous voids shall be permitted in the resin (see Note 8). A continuous void is one that appears in all five consecutive test specimens. The presence of hollow fibers is not considered a void. (Note 8—This requirement is intended to check for continuous voids that could occur due to shrinkage of the resin during processing or as the result of poor consolidation of the fiber and resin matrix during production.)
SECTION 10—OTHER REQUIREMENTS 10.1—Bend radius Bends shall be formed in FRP bars that are made with thermosetting resin and only while the resin is in a physical liquid state (see Note 9). The minimum inside bend radii for factory-formed FRP bar bends are specified in Table 10.1. (Note 9—After the resin has passed the liquid state, bending or alteration of the FRP bar is not possible due to the inability of the fibers to move [or reorient] within the resin matrix. Because thermosetting polymers are highly cross linked, heating the bar on site will not be allowed as it leads to a decomposition of the resin, thus creating a loss of strength in the FRP bar.)
10.2—Strength of bends The strength of bends shall be determined for the purpose of overall product certification (that is, guaranteed value). 10.2.1 The guaranteed strength of bends for product certification shall be measured according to a test method submitted by the manufacturer for acceptance by the purchaser (see Note 10). Testing frequency and number of specimens shall be as indicated in Section 11. The manufacturer shall report the individual test results and the test method. Minimum strength values have not yet been established. (Note 10—ACI 440.3R, Test Method B.5 or B.12, may be considered by the manufacturer for this purpose.) 10.2.2 For a measure of the manufacturer’s quality control and purchaser’s quality assurance on FRP bends, one of the two test methods listed as follows shall be used at a frequency and number of specimens as indicated in Section 11 (see Note 11). The manufacturer shall report the individual test results and the test method. (Note 11—Testing for the manufacturer’s quality control does not require measurement of strength of the bends as per Section 10.2.1.) 10.2.2.1 When it is possible to extract a straight portion of the tail of the bent bar of sufficient length, such an element shall be tested according to ASTM D7205/D7205M. The strength of each specimen shall be not less than the guaranteed strength reported by the manufacturer for the bar of that diameter. 10.2.2.2 When the bend size does not allow for the tensile testing of one of its straight portions, a specimen shall be obtained from the bend and tested for interlaminar
440.6M-5
Table 10.1—Minimum inside bend radius of bent bars Bar size designation
Bend radius, * mm
6
19
10
28
13
38
16
48
19
57
22
67
25
76
29
114
32
127
*
Based on three bar diameters for No. 6 through No. 25, and four bar diameters for No. 29 and No. 32.
(horizontal) shear strength according to ASTM D4475 and for fiber content according to ASTM D2584 or D3171. The manufacturer shall report the individual test results and the test method. Minimum interlaminar shear strength values have not yet been established. The fiber content of each specimen shall be not less than the minimum percent by volume reported in Section 7.1.
SECTION 11—SAMPLING 11.1—Sampling frequency and number of specimens 11.1.1 For the determination of each of the mechanical and durability properties for the manufacturer’s quality control tests and for the purchaser’s quality assurance tests, at least five samples of sufficient length to perform the required tests shall be obtained from each production lot. 11.1.2 For the determination of each of the mechanical and durability properties for product certification (that is, guaranteed and nominal values), at least 25 samples of sufficient length to perform the required tests shall be obtained in groups of five from five different production lots. Tests for the determination of the mechanical and durability properties for product certification shall be repeated at least every 3 years. 11.1.3 For orders of bends in varying quantities that together will comprise a production lot of bends, at the discretion of the purchaser, testing of bends for the manufacturer’s quality control and for the purchaser’s quality assurance may be limited to a minimum of five samples of a 90-degree bend with the smallest bend radius to bar diameter ratio.
11.2— Methods of sample selection
Samples from each production lot to be used for preparing test specimens shall be selected by the manufacturer on a random basis.
SECTION 12—REJECTION 12.1 The purchaser has the option to reject material that fails to conform to the requirements of this specification. Rejection shall be reported to the manufacturer or supplier promptly and in writing.
SECTION 13—PRODUCT CERTIFICATION 13.1 When specified in the purchase order or contract, the purchaser shall be furnished with:
440.6M-6
•
ACI STANDARD
Documentation showing the constituents, their quantities, and their properties as provided by the suppliers; and • Product certification stating that samples representing each production lot have been tested and inspected as indicated in this specification and the requirements have been met. Certifications shall bear the signature of an authorized representative of the bar manufacturer. 13.2 When specified in the purchase order or contract, a report of the results of the manufacturer’s quality control tests and the purchaser’s quality assurance tests shall be furnished. The test report shall include the following for a given production lot traceable to the identifying marking on the FRP straight and bent bars furnished: • Test date and laboratory where testing was performed; • Nominal bar diameter; • Production lot number or identifying marking; • Description of specimens tested, that is, specimen length, free length, and anchorage details; • Results of individual tensile strength tests of each specimen; • Results of dye penetration tests (wicking); and • Description of testing apparatus, that is, load frame type and capacity, extensometer, data acquisition software, and other pertinent details. 13.3 When specified in the purchase order or contract, a report of the test results of product certification shall be furnished. The test report shall include the following for the FRP straight and bent bars furnished: • Test date and laboratory where testing was performed; • Resin matrix, fillers, and additives; • Fiber manufacturer’s specific product identification nomenclature used; • Description of specimens tested, that is, specimen length, free length, and anchorage details; • Description of the testing method when the choice of more than one test method or variation has been specified in this document; • Geometric properties: cross-sectional area and diameter; • Physical properties: fiber content with indication of reference by mass or volume, glass transition temperature, and bar size and dimensions of elliptical bars; • Guaranteed mechanical properties: tensile strength, transverse shear strength (perpendicular to the bar), bond strength, and strength of bent bars;
Table 14.1—Color codes for marking bar sizes Bar size designation
Color*
6
Black
10
Orange
13
Green
16
Red
19
Blue
22
Yellow
25
Purple
29
Gray
32
Brown
*
Color coding should be at least 150 mm of FRP at each end of bars.
• • •
Nominal mechanical properties: tensile modulus of elasticity, and ultimate tensile strain (calculated); Nominal durability properties: moisture absorption and resistance to alkaline environment; and Description of testing apparatus, that is, load frame type and capacity, extensometer, data acquisition software, and other pertinent details.
SECTION 14—MARKINGS 14.1 Each bundle of bars shall be identified with a corresponding production lot number. Production lot numbers shall be printed on each bar or affixed to each bundle by means of a durable tag. 14.2 Each bundle of bars shall be labeled with the following information: • A symbol to identify the manufacturer; • A marking to indicate the classification of fiber (that is, G for glass and C for carbon); • The nominal bar diameter designation (in metric); • A marking to indicate the guaranteed tensile strength; and • A marking to indicate the nominal modulus of elasticity. 14.3 The only marking required for each individual bar shall be the nominal bar diameter designation, and it shall be made by a durable means. Bar markings shall take the form of permanent physical marking of the bar size in metric on the product or permanent color coding applied to the bar as shown in Table 14.1 (see Note 12). (Note 12—Markings will be used at the construction site to verify that the specified bars are being used.)
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Specification for Carbon and Glass Fiber-Reinforced Polymer Bar Materials for Concrete Reinforcement
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