This test method describes the apparatus and procedure for evaluating the lap shear bond properties of wet lay-up or pultruded (shop-fabricated) fiber-reinforced polymer (FRP) composite systems adhesively applied to a flat concrete substrate. The test determines the plateau force that an FRP system can bear before complete debonding from a concrete prism tested using a direct single-lap shear test. This plateau force is reported as bond capacity and may be different from the maximum applied force. The plateau force is then used to determine the interfacial fracture energy and the cohesive material law.
Keywordssingle lap shear; bond; delamination; bond of FRP to concrete
ASTM D30.10 has developed three test methods that deal with the bond of composite laminates. D7616 concerns the bonding of one ply of composite material to a ply of the same material, and is used primarily to develop overlap splice requirements for field applications of FRP composite repair materials. D7522 uses direct tension to extract a round "puck" of composite from a concrete substrate. This test is primarily used for quality control and does not produce shear at the interface of the FRP composite and concrete. Finally, D7958 uses a notched concrete beam with a ply of FRP composite adhered to the bottom to assess the quality of the bond in shear. Unfortunately none of the existing tests provide a direct measure of the force in the composite laminate as the bond is loaded and failed in Mode II (sliding / pull off). These results are critical for the design of FRP composite repairs to concrete, which are generally achieved by bonding composite materials to reinforced concrete structures in the field.Back to Top