Can Hilti Hit RE-500 V3 be used with both, Hot-dipped galvanized and Epoxy Coated Rebar?
Are there any differences in embedment length, capacity, or installation between the two?
Hi Thomas,
Please see the following guidelines regarding the use of epoxy coated rebar.
If the design is based on rebar development theory, please reference ACI 318-14 Table 25.4.2.4 for the applicable modification factor for epoxy-coated rebar. The modification factor may be used in hand calculations or through Hilti’s PROFIS Rebar software. The modification factor increases the development length when compared to an uncoated or zinc coated rebar.
If the design is based on anchor theory, Hilti has performed basic testing for the HIT-RE 500 V3 adhesive anchor with epoxy-coated rebar. Typically, there is no reduction in the ultimate bond stress due to the epoxy coating, but there can be an increase in the tested data scatter / coefficient of variation. The increase appears to be related to the amount of epoxy coating on the bar next to the deformations. If the epoxy coating thickness is fairly uniform, the deformations will typically receive the same coating as the flat area between giving the best bond performance. If the amount of epoxy coating is thicker in the flat areas compared to the deformations, there could be a reduction in capacity.
The published bond stress should be sufficient for design, but it would be prudent to use the Anchor Category 2 phi factor of 0.55 instead of the published Anchor Category 1 phi factor of 0.65 to consider the effects of the higher load scatter. For example, the bond stresses and phi factors for the HIT-RE 500 V3 adhesive anchor with reinforcing bars installed in dry or water-saturated concrete conditions are listed in Table 8 of ESR-3814. Strength reduction factors can be reduced to 0.55 for epoxy-coated rebar as discussed above.
If you have further questions, please reach out to hnatechnicalservices@hilti.com.
Regards,
Ashley