Product Technical Guides : US-EN Post-Installed Rebar Guide - Page 19

Post-Installed Reinforcing Bar Guide
3.0 HOW ARE THEY INSTALLED ?
For example , if a rapid-cure adhesive is specified for a large and deep bar installation , the time required to inject the adhesive may exceed the working time of the polymer . In such cases it may be impossible to insert the bar fully into the hole and / or the adhesive may not reach full strength . In particular , when adhesives are delivered in bulk quantities into a large drilled hole , the exothermic reaction associated with polymerization can result in excessive temperature rise which in turn can result in accelerated cure , further complicating bar installation .
Figure 33 — Cleaning a hole using a compressed air blowout tool .
Hilti provides a number of accessories for cleaning deep drilled holes in accordance with the Instructions for Use . These include matched-tolerance wire brushes , brush extensions for long holes , attachments to facilitate power brushing , air wands , hose extensions , couplers and air nozzles . Hilti Adhesive Anchor Installation Kit ( Figure 31 ) provide the necessary additional components for installation of post-installed reinforcing bars in a single package .
3.6 SELECTION OF ADHESIVE SYSTEM
The suitability of Hilti adhesive systems for post-installed reinforcing bar applications has been verified for a wide variety of jobsite parameters . Nevertheless , the choice of the appropriate Hilti adhesive system ( Figure 34 ) and injection equipment ( Figure 35 ) for post-installed reinforcing bar installations is to a degree dependent on jobsite parameters ; see Section 4.1 .
Hilti HIT-RE 500 V3
Hilti HIT-HY 200 V3
Figure 34 — Hilti anchoring adhesives suitable for post-installed reinforcing bar connections .
Figure 35 — Using Hilti HDE-500 A22 cordless adhesive battery dispenser in combination with Hilti HIT-RE 500 V3 / Hilti HIT-HY 200 V3 for smaller bar diameters .
Conversely , injection of adhesives under sub-zero conditions can result in elevated viscosity , likewise making manual adhesive injection and bar installation difficult or impossible .
Basic considerations associated with adhesive selection should include :
• Can the adhesive be injected and the reinforcing bar installed within the gel time of the adhesive ?
• Is the appropriate injection equipment available , including all necessary accessories , to ensure correct dispensing and mixing ?
• Is the adhesive suitable for the concrete temperature and moisture conditions , hole orientation and drilling method ?
• What mechanical effort or equipment is required to inject the adhesive and to install the reinforcing bar into the adhesive filled hole ?
• How will the bar be held in place during adhesive cure ?
Note : Adhesives which have not been properly verified for post-installed reinforcing bar applications should not be used for structural or safety-related applications .
17 2021