Preserving exposed rebar after saw cutting

[canwesteng]

As part of a retrofit of a building, we will be saw cutting concrete, which will leave rebar exposed. My concern is the exposed rebar will start to corrode and eventually cause decay of the whole slab. Does anyone have experience in this type of situation, and what might be recommended to preserve the bar?

 

[H57]

What environment will the rebar be exposed to? Recommendations would vary depending on whether this is in an interior conditioned space or an exterior space or exposed to chemicals, etc.

 

[canwesteng]

Industrial environment, but not exposed to much. Just in a powerhouse, supporting some generators

 

[BUGGAR]

We've used grease-filled pvc tubes. We just hired an industrial lube truck to come out and squirt grease into the tubes for a bunch of exposed rebar that had to last two years for future construction. It worked.

 

[canwesteng]

It should just be the ends exposed. I'm think of getting the contractor to drill the bar out 3 inches and grout the holes. They'll probably hate that though.

 

[BUGGAR]

Sorry, I didn't understand what you were doing. We always require chipping out the concrete, cutting off the bar for a minimum cover and grouting back. I haven't seen a successful drilling of the rebar only.

 

[canwesteng]

To do that we'd have to grout a vertical plane, is that possible? We're cutting back a suspended slab

 

[KootK]

I usually just cover the bar ends with zinc rich paint.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[Teguci]

Worst case, epoxy/zinc paint the ends and put flashing over the edge. Worst case would be a pickling line, which this is not. Just leave it be and tell everyone you were going for an industrial look.

 

[hokie66]

I would just paint the end with a rust inhibitor, then use an acrylic coating on the concrete edge.

 

[MrHershey]

Our standard detail is to have them chip back a bit , cut the bar and apply corrosion inhibitor to end, and then patch back with nonshrink grout or other patching material as a cap.

Don't know that I'd necessarily mind just cutting and painting the end for an interior condition as long as owner/architect isn't concerned with being able to see it. Exterior condition I think I'd want the cover instead of the paint.