Greased Rebar

[MotorCity]

On one of my recent jobs, a newly hired rod buster apparently misunderstood his task. Instead of greasing the forms for ease in removal, he GREASED ALL OF THE REBAR!!!! The reinforcement was for a continous footing and wall foundation for a 4-story building. The field engineer ordered all of the rebar to be removed and replaced or cleaned to his satisfaction. Unable to remove the grease, all of the rebar was re-installed. I have seen rebar greased before but only in greased caps at expansion joints. Obviously the grease would have an effect on the bond with the concrete. However, if placed in the correct location it should still take the tension forces for which it was intended. Any thoughts on this?

 

[dicksewerrat]

My thought is that greased bars will not be of any use in a footing. There will be no bond with the concrete and no way to transfer tension from the concrete to the bar. They will however be expensive filler and introduce weakened areas in the concrete.

 

[JAE]

That's right, in a footing, the continuous rebar would be there for crack control and perhaps some flexural strength. If the bars are greased, despite the deformations, the bond would be seriously reduced and the reinforced concrete would not be able to develop tension in the rebar.

 

[kenvlach]

On the bright side, the inevitable recycling will be easier!

 

[Focht3]

Yup - [blue]dicksewerrat[/blue] is dead-on right. The rebar is absolutely useless for the intended use. The field engineer was absolutely correct in his assessment and direction.

Personally, I would have used a steam cleaner and power washer - remove and replace would be awfully expensive. But it wasn't my call -



Please see FAQ731-376 for great suggestions on how to make the best use of Eng-Tips Fora.

 

[cap4000]

The rod buster should on his time clean each one with something like lacquer thinner then power wash.The form release oil hopefully will come off. If that fails, replacement is necessary. Good Luck.

 

[Qshake]

No self-respecting contractor would clean that rebar. Only if it were the only rebar within two hundred miles or two months of delay.

Otherwise the contractor is going to re-order or look for substitutions in his yard or even in your backyard. If the rebar found is larger and fewer of found you'll get an RFI asking to use it. If the rebar is smaller but more of it found, you'll get a similar RFI!

 

[JAE]

You know what's scary is that the rejected rebar might be wiped off with a rag and used on some other project with the inspector unaware of its condition.

 

[Qshake]

JAE, you're absolutely right. That is a scary thought yet one that is likely to happen!

 

[jike]

It will probably go into the contractor's boneyard and it will be used on the next project when they are short of material.

 

[Maury]

Was he trying to oil the forms after they were set?

 

[MotorCity]

He had no intention of oiling the forms (they were oiled later). The reinforcement had already been assembled in place and the forms were laying on the ground (oil side up)on each side of the future foundation. As soon as the forms were oiled, they were going to be erected. I would expect that they are easier to oil on the ground than in place. The inspector noticed that the rebar "seemed have an unusual shine". Just when you think you've seen it all........