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ASTM International - ASTM D7957/D7957M-17

Standard Specification for Solid Round Glass Fiber Reinforced Polymer Bars for Concrete Reinforcement

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Organization: ASTM International
Publication Date: 1 August 2017
Status: active
Page Count: 5
scope:

1.1 This specification covers glass fiber reinforced polymer (GFRP) bars, provided in cut lengths and bent shapes and having an external surface enhancement for concrete reinforcement. Bars covered by this specification shall meet the requirements for geometric, material, mechanical, and physical properties described herein.

1.2 Bars produced according to this standard are qualified using the test methods and must meet the requirements given by Table 1. Quality control and certification of production lots of bars are completed using the test methods and must meet the requirements given in Table 2.

TABLE 1 Property Limits and Test Methods for QualificationA

Property Limit Test Method
Mean Glass Transition Temperature Midpoint temperature ≥100 °C [212 °F] ASTM E1356
Mean Degree of Cure ≥95 % ASTM E2160
Mean Measured Cross-Sectional Area Table 3 ASTM D7205/D7205M, subsection 11.2.5.1
Guaranteed

B Ultimate Tensile Force

Table 3 ASTM D7205/D7205M
Mean Tensile Modulus of Elasticity ≥44,800 MPa [6 500 000 psi] ASTM D7205/D7205M
Mean Ultimate Tensile Strain ≥1.1 % ASTM D7205/D7205M
Guaranteed

B Transverse Shear Strength

≥131 MPa [19 000 psi] ASTM D7617/D7617M
Guaranteed

B Bond Strength

≥7.6 MPa [1100 psi] ASTM D7913/D7913M
Mean Moisture Absorption to Saturation ≤1.0 % to saturation at 50 °C [122 °F] ASTM D570, subsection 7.4
Mean Alkaline Resistance ≥80 % of initial mean ultimate tensile force following 90 days at 60 °C [140 °F] ASTM D7705/D7705M, Procedure A
Guaranteed

B Ultimate Tensile Force of Bent Portion of Bar

≥60 % of the values in Table 3 ASTM D7914/D7914M

(A) For the determination of the mean and guaranteed properties, at least 24 samples shall be obtained in groups of eight or more from three or more different production lots. The mean and guaranteed properties shall satisfy the limits.(B) Guaranteed property is defined in 3.2.5.

TABLE 2 Property Limits and Test Methods for Quality Control and CertificationA,B

Property Limit Test Method
Fiber Mass Content ≥70 % ASTM D2584 or ASTM D3171
Glass Transition Temperature Midpoint temperature ≥100 °C [212 °F] ASTM E1356
Degree of Cure ≥95 % ASTM E2160
Measured Cross-Sectional Area Table 3 ASTM D7205/D7205M, subsection 11.2.5.1
Ultimate Tensile Force Table 3 ASTM D7205/D7205M
Tensile Modulus of Elasticity ≥44 800 MPa [6 500 000 psi] ASTM D7205/D7205M
Ultimate Tensile Strain ≥1.1 % ASTM D7205/D7205M
Moisture Absorption in 24 h ≤0.25 % in 24 h at 50 °C [122 °F] ASTM D570, subsection 7.4

(A) For the determination of each of the property limits, five random samples shall be obtained from each production lot. Each individual sample shall satisfy the property limits.(B) For bent bars, the tests are performed on the straight portion of the bars.

TABLE 3 Geometric and Mechanical Property Requirements

Bar
Designation
No.
Nominal Dimensions Measured Cross-Sectional Area Limits
mm

2 [in.2]

Minimum
Guaranteed
Ultimate
Tensile Force
kN [kip]
Diameter
mm [in.]
Cross-Sectional Area
mm

2 [in.2]

Minimum Maximum
M6 [2] 6.3 [0.250] 32 [0.049] 30 [0.046] 55 [0.085] 27 [6.1]
M10 [3] 9.5 [0.375] 71 [0.11] 67 [0.104] 104 [0.161] 59 [13.2]
M13 [4] 12.7 [0.500] 129 [0.20] 119 [0.185] 169 [0.263] 96 [21.6]
M16 [5] 15.9 [0.625] 199 [0.31] 186 [0.288] 251 [0.388] 130 [29.1]
M19 [6] 19.1 [0.750] 284 [0.44] 268 [0.415] 347 [0.539] 182 [40.9]
M22 [7] 22.2 [0.875] 387 [0.60] 365 [0.565] 460 [0.713] 241 [54.1]
M25 [8] 25.4 [1.000] 510 [0.79] 476 [0.738] 589 [0.913] 297 [66.8]
M29 [9] 28.7 [1.128] 645 [1.00] 603 [0.934] 733 [1.137] 365 [82.0]
M32 [10] 32.3 [1.270] 819 [1.27] 744 [1.154] 894 [1.385] 437 [98.2]

1.3 The text of this specification references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables) shall not be considered as requirements of the specification.

1.4 The following FRP materials are not covered by this specification:

1.4.1 Bars made of more than one load-bearing fiber type (that is, hybrid FRP).

1.4.2 Bars having no external surface enhancement (that is, plain or smooth bars, or dowels).

1.4.3 Bars with geometries other than solid, round cross sections.

1.4.4 Pre-manufactured grids and gratings made with FRP materials.

1.5 This specification is applicable for either SI (as Specification D7957M) or inch-pound units (as Specification D7957).

1.6 The values stated in either inch-pound units or SI units are to be regarded as standard. Within the text, the inch-pound units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.

1.7 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.

1.8 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.

Document History

ASTM D7957/D7957M-17
August 1, 2017
Standard Specification for Solid Round Glass Fiber Reinforced Polymer Bars for Concrete Reinforcement
1.1 This specification covers glass fiber reinforced polymer (GFRP) bars, provided in cut lengths and bent shapes and having an external surface enhancement for concrete reinforcement. Bars covered...
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