1.1 This test method describes the apparatus and procedure for evaluating the bond strength of wet lay-up or pultruded (shop-fabricated) fiber-reinforced polymer (FRP) laminate systems adhesively bonded to a flat concrete substrate. The test determines the bond stress (shear averaged over the bonded area) that an FRP system can bear before detaching from a concrete beam tested in flexure. Failure will occur along the weakest plane within the system comprised of the FRP laminate, adhesive, and substrate. 1.2 This test method is primarily used for quality control and assessment of FRP systems and is intended for use with adhesive-applied composite materials. 1.3 This test method is appropriate for use with FRP systems having any fiber orientation or combination of ply orientations comprising the FRP laminate, although the test condition only considers forces in the direction parallel to the beam. 1.4 The values stated in either SI units or inch-pound units are to be regarded separately 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 must be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. 1.5 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 and health practices and determine the applicability of regulatory limitations prior to use.
This is a simple method for assessing the bond of FRP composite repair materials to concrete. The method uses a simple modulus of rupture flexural concrete specimen as the substrate for the FRP composite repair laminate. A simple shear test such as that proposed herein is needed as the only existing ASTM method for assessing bond of FRP to concrete is Test Method D7522, and this test places the bond in direct tension and not in shear. Shearing of the bondline is a common failure mode for FRP laminate to concrete joints and shear strength of the bondline is a governing factor in design of many concrete beam repairs with FRP.
Keywordswet lay-up FRP; pultruded (shop-fabricated) FRP; composite materials; bond shear strength; concrete repair and rehabilitation; beams
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top
Ballot Item Approved as D7958-2017 and Pending Publication