Existing Cast-in-Place concrete floor slab with crack and oil infiltration. 2

[timj58]

The situation is; a cast-in-place elevated reinforced concrete floor slab has a vertical hairline crack completely though it. It has been hypothized that the crack is due to thermal expansion and not due to flexural loading. The slab is supporting an 500 hp electric motor and hydralic gearbox. This gearbox has been leaking oil which has infiltrated into and completely though this hairline crack in the floor slab.

Question: Does hydralic oil interact with concrete and reduce its strength?

Thanks in advance for any replys.

Tim

 

[MiketheEngineer]

A vibrating 500 hp motor and gear box could do that - plus now you might have an EPA problem. Hydro chemicals and concrete do not generally play nicely.

Hoe many concrete gasoline storage tanks have you seen??

Clean it, patch it and seal it

 

[Ron]

The oil will not react with the concrete, nor will it cause it to lose strength, other than to displace or remove moisture from the concrete.

The crack could be vibration induced or at least exacerbated by the vibration. You indicate it is hairline in width, so probably just a drying shrinkage crack. Thermal expansion doesn't usually cause concrete to crack, and besides, it takes a large thermal gradient to move concrete very much.

 

[cvg]

fix the gearbox to stop the leak and clean the floor? Put down a drip pan?

 

[FiniteElement2012]

Hairline crack has to be surfacial only and not through crack. Through crack may be designated as structural crack. Give sometime to the crack to watch its behavior specially around extreme temperature days.
If it starts aggravating than may want to do core drill across the crack and inspect cored sample and soil underneath. IF soil displaced, inject grout to regain the bearing strength otherwise just use crack fixing grout (forgot the name). Just throwing ideas