I don’t see anything in CSA A23.3 or your ESRs for RE 500 V3 or HY200 V3 on the use with GFRP. Do you have any guide line on using adhesives GFRP Rebars?
Hi,
Unfortunately, Fiber Reinforced Polymer (FRP) and Glass Fiber Reinforced Polymer (GFRP) deformed reinforcement (rebar) with Hilti adhesive is outside the scope of Hilti’s published technical data.
However, please refer to the discussion below for more information:
Hilti has performed limited tension testing with Hilti HIT-RE 500-SD adhesive and Fiber Reinforced Polymer (FRP) and Glass Fiber Reinforced Polymer (GFRP) deformed reinforcement (rebar). Confined tension tests in accordance with ICC-ES Acceptance Criteria for Post-Installed Adhesive Anchors in Concrete Elements (AC308) table 3.2, test series 1a (dry concrete, borehole cleaning as prescribed by manufacturer, confined tension), has shown reductions in the bond stress when compared to steel rebar of equivalent size. The testing has shown reductions of up to 50% and the failure is typically a loss of adhesion between the adhesive and the FRP or GFRP rebar, and occasionally the deformations of the FRP or GFRP rebar have sheared off during the test.
Due to the reduction in bond stress, it is recommended to perform on-site tension testing when using FRP or GFRP rebar with Hilti HIT-RE 500-SD. As a guideline design bond stress, a reduction of 0.5 could be applied to the published bond stress for HIT-RE 500-SD, and on-site proof load testing should be performed to verify this load level. The FRP or GFRP rebar design strengths need to be evaluated separately as Hilti has no design values for this strength. Please note that no testing for seismic loading has been performed. Proof load level and number of anchors to test should be directed by the project Engineer of Record (EOR) and results should be approved by EOR. As a guideline, the proof load level could be determined by ACI 355.4, section 13.3.4.
Although the info above references an outdated adhesive, HIT-RE 500-SD, the general information remains relevant. We do not have more recent testing, however, the methodology described above could be considered by the engineer of record, using HIT-RE 500 V3 as a replacement for HIT-RE 500-SD. The final decision and design is at the discretion of the engineer on the project, and the engineer on the project would need to consider using engineering judgment or on-site evaluation to account for potential variability in performance.
Kind regards,
Oscar
