ASTM International - ASTM D7957/D7957M-17
Standard Specification for Solid Round Glass Fiber Reinforced Polymer Bars for Concrete Reinforcement
|Publication Date:||1 August 2017|
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
|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 188.8.131.52|
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|
B Transverse Shear Strength
|≥131 MPa [19 000 psi]||ASTM D7617/D7617M|
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|
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) Guarantee
TABLE 2 Property Limits and Test Methods for Quality Control and CertificationA,B
|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 184.108.40.206|
|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 |
|Nominal Dimensions|| Measured Cross-Sectional Area Limits |
| Minimum |
| Diameter |
| Cross-Sectional Area |
|M6 ||6.3 [0.250]||32 [0.049]||30 [0.046]||55 [0.085]||27 [6.1]|
|M10 ||9.5 [0.375]||71 [0.11]||67 [0.104]||104 [0.161]||59 [13.2]|
|M13 ||12.7 [0.500]||129 [0.20]||119 [0.185]||169 [0.263]||96 [21.6]|
|M16 ||15.9 [0.625]||199 [0.31]||186 [0.288]||251 [0.388]||130 [29.1]|
|M19 ||19.1 [0.750]||284 [0.44]||268 [0.415]||347 [0.539]||182 [40.9]|
|M22 ||22.2 [0.875]||387 [0.60]||365 [0.565]||460 [0.713]||241 [54.1]|
|M25 ||25.4 [1.000]||510 [0.79]||476 [0.738]||589 [0.913]||297 [66.8]|
|M29 ||28.7 [1.128]||645 [1.00]||603 [0.934]||733 [1.137]||365 [82.0]|
|M32 ||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.
1.5 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.