Field Handling Techniques for Epoxy Coated Rebar
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Field
Handling Techniques for Epoxy-Coated Rebar
Proper field handling techniques for epoxy-coated
reinforcing bars.
When it comes to epoxy coated rebar, quality control at the job site is just as important as it is during the manufacturing process.
Remember that epoxy-coated rebar delivered at the job site has gone through considerable processing and testing prior to shipping. The epoxy coaters go to great lengths to ensure that the epoxy coating is of good quality and free of defects, because if the epoxy coating is damaged, salts and water can seep through it and attack the steel.
At the jobsite, it's equally important to take extra precautions when handling and storing epoxy coated reinforcing bars so that they don't get damaged.
Here are the five basic steps for the correct field handling techniques of epoxy-coated rebar:
- Receipt of Material
To ensure quality on arrival at the job site, the manufacturer has carefully loaded the epoxy-coated rebar onto the trailer with nylon straps and placed the bars on wooden timbers.
Before unloading a bundle of coated rebar, make certain that the tie-downs are secure. Check for proper padding and bar separation on the transport. Visually inspect epoxy-coated bars for damage. Check the coating on sheared ends. If uncoated or partially coated sheared ends are found, patch them and any other damage immediately.
When unloading a bundle of coated rebar, take care not to damage the epoxy coating. Unload as close to the area of placement as possible. It's important that the coated rebar doesn't come in contact with the bare metal or rough surface of the trailer because damage can occur.
Use power lift equipment for unloading. Handling equipment should have protected contact areas. Use nylon slings or straps. Never use chains or bare cables to unload.
If a bundle is long, use spreader bars or additional nylon straps at pick-up points. This helps to prevent sagging of bundles which prevents bar-to-bar abrasions.
- Storage
When storing the rebar at the job site, always use wooden dunnage or other protective cribbing between the ground and the rebar to prevent sagging. Epoxy-coated rebar shouldn't be stacked directly on the ground or on other unprotected surfaces. Remember to leave aisle space between stacks to enable easy access. To avoid sagging, the rebar should be placed on a flat or relatively level terrain with timbers close together.
If a relatively large quantity of materials has to be stored, bundles should be stacked with adequate blocking in place between the layers of bundles and if rebar is stored in the elements outdoors for more than two months, cover the rebar with opaque plastic sheeting.
- Placing
Epoxy coated rebar requires the same hoisting and handling techniques and precautions for placing as discussed for unloading. It requires more careful handling during placing than uncoated bar.
Make sure all epoxy bars are lifted and set into place. Avoid dragging the rebar over other bars or any other abrasive surface. Use two workers to support and carry the rebar. Whenever possible, try to avoid walking on epoxy coated rebar. By simply using common sense, the need for repairs will be reduced.
Use non-corrosive, non-conductive bar supports such as plastic bar supports or metal bar supports coated with epoxy, nylon, or PVC to eliminate a potential source of corrosion and to prevent damage to the coated rebar.
Tie wire should be coated to minimize damage or cutting into the bar's coating, and to avoid creating a direct electrical contact between intersecting bars. Many mechanical coupling devices are available for use with epoxy-coated bar. Couplers
should be pre-coated with fusion bonded epoxy coating.
After installing the coupler, repair any damage to the coating. When welding splices, all welds and spliced members must be coated with the same material used for any coated bar damage.
Field cutting of epoxy-coated rebar should be avoided and only permitted with specifier-owner approval. Should field cuts be needed, repair all cut ends immediately with the same patch material.
- Final Inspection & Repair
Once the rebar is placed, a final inspection must be made to locate any unrepaired placing and handling damage. When making repairs to damaged areas, it's important to use the following procedures:- Follow the manufacturer's recommended mixing procedures when mixing two-part mixing repair compound.
- Mix the epoxy prior to use according to the manufacturer's recommended procedures.
- Use a wire brush to remove all contaminants from damaged areas prior to applying the patch material.
- A paintbrush should be used to apply the patch compound to the cleaned damaged area.
- Avoid careless use of the patch compound on the rebar. Apply the compound to the patch are with sufficient, but not excessive overlap with the adjacent sound coating
- When in doubt about whether an area needs repairing or not, always repair it.
- Allow patch material sufficient curing time
as specified by the materials instructions before pouring the concrete.
Patch materials generally
cure more slowly at lower temperatures, and some require a minimum of 8 hours
to cure.
- Concreting
When pouring the concrete, take caution when waling on the rebar not to drop anything such as hand tools or construction materials on the placed bars. To complete the pour, follow these guidelines:- Set up runways for concrete buggies and hoses and properly support them.
- Maneuver carefully to minimize damage to the coating and to prevent shifting of placed bars.
- When vibrating concrete, use a non-metallic or rubber vibrating head to minimize damage to epoxy-coated rebar. Metal heads can cause damage to the coated bars within the concrete.
Experience has shown that using common sense precautions and some extra care will eliminate most jobsite damage and ensure the corrosion protection benefits of the epoxy coated rebar. Most importantly, remember that any damage that may occur during these processes should be cleaned and repaired.
