440 3R 04 Guide Test Methods for Fiber Reinforced Polymers

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440 3R 2 ACI COMMITTEE REPORT, CONTENTS The mechanical behavior of FRP differs from the behavior. Part 1 General p 440 3R 2 of steel reinforcement FRP materials are anisotropic due to. 1 1 Introduction the fiber orientation in the bars and laminates and are. 1 2 Scope characterized by high tensile strength only in the direction of. 1 3 Existing ASTM test methods the reinforcing fibers This anisotropic behavior affects the. 1 4 Definitions shear strength and dowel action of FRP bars and the bond. 1 5 Notation performance of FRP bars to concrete, Part 2 Test methods for FRP bars for concrete FRPs are available with a wide range of mechanical. structures p 440 3R 7 properties tensile strengths bond strengths and elastic. B 1 Test method for cross sectional properties of FRP bars moduli Generally FRP concrete reinforcements are not. B 2 Test method for longitudinal tensile properties of covered by national material standards as few such stan. FRP bars dards exist Instead manufacturers of FRP provide test. B 3 Test method for bond strength of FRP bars by data and recommend design values based on these test data. pullout testing Unfortunately also due to the lack of material standards few. B 4 Test method for transverse shear strength of FRP bars standard test methods exist for FRP concrete reinforcements. B 5 Test method for strength of FRP bent bars and Therefore it is difficult to compare test results between. stirrups at bend locations product manufacturers In addition research has considered. B 6 Accelerated test method for alkali resistance of FRP the durability of FRP concrete reinforcements in environ. bars ments containing moisture high and low temperatures and. B 7 Test method for tensile fatigue of FRP bars alkaline environments Test methods that allow for the. B 8 Test method for creep rupture of FRP bars comparison of mechanical property retention in a wide range. B 9 Test method for long term relaxation of FRP bars of standard environments are needed so that durable FRP. B 10 Test method for performance of anchorages of reinforced concrete structures can be ensured. B 11 Test method for tensile properties of deflected FRP bars 1 2 Scope. B 12 Test method for determining the effect of corner This document provides model test methods for deter. radius on tensile strength of FRP bars mining the short term and long term mechanical properties. of FRP reinforcing bars grids and tendons for concrete. Part 3 Test methods for FRP laminates for both prestressed and nonprestressed and for FRP laminates. concrete and masonry p 440 3R 30 as external reinforcement for concrete structures As noted in. L 1 Test method for direct tension pull off test, the individual methods most of the methods for bars are also. L 2 Test method for tension test of flat specimen, suitable for tendons and sections cut from grids Where. L 3 Test method for overlap splice tension test, necessary the tests consider the bars and laminates acting in.
References p 440 3R 36 concert with concrete For the most part however these tests. R 1 Guides and related standards are considered to be material tests and not component or. R 2 Conference proceedings structural tests, R 3 Individual papers reports and theses These model test methods are intended to be considered. modified and adopted either in whole or in part by a U S. Appendix A Anchor for testing FRP bars under national standards writing agency such as ASTM Interna. monotonic sustained and cyclic tension, p 440 3R 38 tional or AASHTO The publication of these test methods by. ACI Committee 440 is an effort to aid in this adoption. Appendix B Methods for calculating tensile The document contains only test methods and not material. properties of flat specimen p 440 3R 39, standards The individual test methods contained in this. PART 1 GENERAL document do not specify minimum material properties that. 1 1 Introduction must be met for the materials to be considered acceptable for. Conventional concrete structures are reinforced with use Guidance on deciding whether a material is acceptable. nonprestressed steel prestressed steel or both Recently based on test results is made in the material specifications. composite materials made of fibers embedded in a polymeric and design provisions that complement these test methods. resin also known as fiber reinforced polymers FRPs have ACI 440 1R ACI 440 2R. become alternatives to steel reinforcement for concrete The test methods presented in this document are the. structures Because FRP materials are nonmetallic and recommendations of ACI Committee 440 and have not been. noncorrosive the problems of steel corrosion are avoided adopted by ACI as standards As such they are for the most. with FRP reinforcement Additionally FRP materials part written in nonmandatory language using should and. exhibit several properties such as high tensile strength that may rather than shall and must In keeping with the. make them suitable for use as structural reinforcement FRP usual test method format however some language is imper. materials are supplied as bars for reinforced and prestressing ative Fill a cylinder with water rather than A cylinder. applications and in flat sheets or laminates for use as repair should be filled with water Although typically considered. materials for concrete structures to be mandatory language the use of imperative language in. GUIDE TEST METHODS FOR FIBER REINFORCED POLYMERS 440 3R 3. these test methods is for readability and remain as B. committee recommendations only If an architect or engineer bar FRP a composite material formed into a long. desires one of the test methods to be part of the contract slender structural shape suitable for the internal reinforcement. documents all of the nonmandatory language would need to of concrete and consisting of primarily longitudinal unidirec. be restated into mandatory language tional fibers bound and shaped by a rigid polymer resin. material The bar may have a cross section of variable shape. 1 3 Existing ASTM test methods commonly circular or rectangular and may have a deformed. The recommended test methods provided herein are based or roughened surface to enhance bonding with concrete. on the knowledge obtained from research results and literature bending angle the angle formed by the straight sections. worldwide Relevant ASTM standards are referenced in the of a specimen on either side of the deflector. individual methods others are listed in Table 1 1 In many bending diameter ratio the ratio of the external diameter. cases existing ASTM test methods are appropriate to deter. of the deflector surface in contact with the FRP bar to the. mine material properties for FRP bars and laminates Where. diameter of the FRP bar, such methods are completely acceptable for FRP reinforce. ments no new method has been proposed The new methods bending tensile capacity the tensile capacity at failure. that are provided have been developed for one or more of the of a specimen within the deflected section. following reasons bonded length the length of the test bar that is in contact. 1 To provide a test method where no current method exists with concrete. 2 To provide more detailed requirements that are specific braiding intertwining fibers in an organized fashion. to FRP concrete reinforcing bars or laminates such as details. on how to grip the reinforcements in the test fixture C. 3 To adapt a test method originally developed for steel CFRP carbon fiber reinforced polymer. reinforcing bars to work with FRP bars or characteristic length for bars or tendons that have a. 4 To provide calculated test results that are compatible repeating surface deformation pattern the characteristic. with other ACI documents length is the distance in mm of this pattern For a spiral. Table 1 1 lists specific ASTM test methods and comple pattern the characteristic length is the pitch. mentary ACI 440 methods for various material properties coefficient of thermal expansion CTE a measure of. Where both ASTM and ACI 440 test methods exist the the relative change in linear dimension in a material based on. differences between the methods are summarized Hundreds a unit increase in temperature of that material Note Due to. of ASTM test methods are applicable to FRP composites and the anisotropy of FRPs the CTE in the longitudinal direction. organic polymers The table only describes key material of the rod is likely to be different from that measured in the. properties and selected ASTM tests that can be used to deter transverse direction. mine these properties For some properties ASTM provides composite a combination of one or more materials. more than one test procedure The table does not attempt to differing in form or composition on a macroscale Note The. discuss the differences between various ASTM test methods constituents retain their identities that is they do not. dissolve or merge completely into one another although. 1 4 Definitions they act in concert Normally the components can be physi. The following definitions clarify terms that are not cally identified and exhibit an interface between one another. commonly used in reinforced concrete practice,creep time dependent deformation or strain under.
sustained load or stress, AFRP aramid fiber reinforced polymer creep rupture material failure due to deformation. accumulated strain caused by creep, aging the process of exposing materials to an environ. ment for an interval of time creep rupture capacity the load at which failure. alkaline having a pH greater than 7 OH concentration occurs after a specified period of time from initiation of a. greater than 1 10 7 M sustained load, anchorage a device at the ends of an FRP bar that grips creep rupture strength the stress causing failure after a. the bar allowing a minimum of slip and transfers specified period of time from initiation of a sustained load. prestressing load from the tendon to the concrete members creep rupture time the lapsed time between the start of. anchorage reinforcement the latticed or spiral reinforcing a sustained load and failure of the test specimen. steel or FRP bars as confining reinforcement connected with creep strain the differential change in length per unit. the anchorage and arranged behind it length occurring in a specimen due to creep. anchoring section the FRP bar section embedded in the cure to irreversibly change the properties of a thermo. anchorage and anchorage reinforcement including the setting resin by chemical reaction such as condensation. surrounding concrete ring closure or addition Note Cure can be accomplished. average load stress the mean value of the maximum by adding curing cross linking agents with or without. and minimum repeated loads stresses heat and pressure. 440 3R 4 ACI COMMITTEE REPORT, Table 1 1 Test methods for bars used for reinforcing or prestressing concrete. ASTM test ACI 440 test,Property method s method Summary of differences.
Cross sectional area B 1 No existing ASTM test method available. Longitudinal tensile strength ACI method provides detailed information on anchoring bars in the test fixture ACI method also. and modulus D 3916 B 2 provides procedural requirements for attachment of elongation reading devices on bar with. various deformation patterns, ASTM Pullout Test C 234 has been withdrawn and as written did not provide adequate. specimen size to prevent splitting of concrete cylinder when using FRP bars. Bond properties A 944 B 3 The only remaining ASTM test method for bond of steel bars to concrete is beam end test. method A 944 which has not been modified for use with FRP bars Ongoing work by ACI. Committee 440 is expected to produce beam bond test methods. D 3846 The ACI method focuses on dowel action of bars and does not overlap with existing ASTM methods. Shear strength B 4 that focus mainly on beam shearing failure modes Bar shear strength is of specific concern for. D 2344 applications where FRP rods are used to cross construction joints in concrete pavements. Bent bar capacity B 5 No existing ASTM test methods available. Durability properties B 6 No existing ASTM test method available. Fatigue properties D 3479 B 7, Creep properties D 2990 B 8 ACI methods provide specific information on anchoring bars in the test fixtures and on attaching. elongation measuring devices to the bars The ACI methods also require specific calculations that. D 2990 are not provided in the ASTM methods,Relaxation properties B 9. Anchorage properties B 10 No existing ASTM test methods available. Tensile properties of B 11 No existing ASTM test methods available. deflected bars, Effect of corner radius on B 12 No existing ASTM test method available. Flexural properties No ACI methods developed,Coefficient of thermal E 831.
expansion No ACI methods developed, Glass transition temperature No ACI methods developed. Volume fraction No ACI methods developed, Test methods for laminates used as strengthening and repair materials. Direct tension pulloff D 4551 L 1 ACI method provides specific requirements for specimen preparation not found in the ASTM test. Tensile strength and modulus D 3039 L 2 ACI method provides for calculating tensile strength and modulus on gross cross sectional and. equivalent fiber area basis, Lap shear strength L 3 ACI method provides specific requirements for specimen preparation. Bond strength No ACI methods developed, D development length length of embedded reinforcement. deflected section the section of an FRP bar that is bent required to develop the tensile capacity. ACI Committee Reports Guides Standard Practices and Commentaries are intended for guidance in planning designing executing and inspecting construction This document is 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 The

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