Textured Epoxy-Coated Hooked Bars

Abstract

These are the slides from a presentation given at ACI Concrete Convention on 03/30/2025.The ACI Building Code and AASHTO Bridge Specifications require the development lengths of epoxy-coated hooked bars to be 20 percent longer than for uncoated bars. A new textured epoxy coating produced by Sherwin-Williams provides corrosion protection along with improved bond strength and damage tolerance. Tests have demonstrated that the bond strength of straight textured epoxy-coated reinforcement (TECR) satisfying ASTM A1124 is equivalent to the bond strength of uncoated bars. Tests are now underway to compare the anchorage strengths of textured epoxy-coated and uncoated hooked bars that may permit the use of a coating factor of 1.0 for both within the ACI Building Code and the AASHTO Bridge Specifications. This study examines the bond strength of TECR using beam-end specimens, as required by ASTM A1124, and the anchorage strength of hooked TECR using simulated beam-column joint specimens. To date, 12 beam-end specimens - six pairs of TECR and uncoated bar specimens - were tested in accordance with ASTM A944 and A1124, and one pair of simulated beam column joint specimens containing TECR and uncoated No. 11 bars, embedded at 22 in. with a concrete compressive strength of 5000 psi, was tested. Figures 1 and 2 show the test setups for the beam-end specimens and the simulated beam column joint specimens, respectively. The TECR exhibited a bond strength equal to 100.3 percent of that of uncoated reinforcement from the same heat of steel in the beam-end test. Similarly, the TECR exhibited an anchorage strength equal to 107.3 percent of that of uncoated reinforcement in the simulated beam column specimen test. Additional tests are planned and will be reported