Does concrete corrode aluminum ?

Question

Does concrete corrode aluminum ?

yirmidokuz (Materials)

(OP)

23 Apr 16 06:24

Hello dear engtip members. This is my first post into this discussion board.

I am currently working in a aluminum extrusion company.
Last week my manager, proposed a project that is construction of sun-shields for our parking lot of the factory.
The construction will be made out of aluminum.

I am thinking the use aluminum profiles to construct that.
First I will dig the ground and then land the aluminum profile in some depth with concrete.

But I wonder If is there any chemical attack would occur from concrete to aluminum?

Or

What happens if I use steel rods for reinforcement of profiles ?

Thanks

dik (Structural) · Answer 1 · 2016-04-25 05:01:22

The high pH of concrete corrodes aluminum if in contact. Aluminum has to be isolated with a suitable ocating.

Dik

hokie66 (Structural) · Answer 2 · 2016-04-25 06:37:40

Concrete and aluminum don't mix. All specifications should prohibit aluminum in concrete.

http://www.theconcreteproducer.com/concrete/how-do...

weldstan (Materials) · Answer 3 · 2016-04-27 21:55:20

Ditto the above, especially when in contact with water.

yirmidokuz (Materials) · Answer 4 · 2016-04-28 06:17:24

Acoording to the link given above;

Quote:
In most situations, the contact time between aluminum and fresh concrete is relatively short, so it normally doesn't cause a problem. Therefore, you can use an aluminum truck bed to haul concrete for a short duration without any adverse effect, as along as it's cleaned after use.

But serious consequences can arise in situations of long-term contact. First, a significant corrosion of aluminum embedded in concrete can occur. The corrosion can cause expansion of the concrete and subsequent cracking of hardened concrete.

At my situation, aluminum bars will be in touch with fresh concrete till the concrete becomes dry. Well, after the concrete becomes dry the aluminum bar would be embedded into it of course. I wonder, in this case, long term contact with concrete would cause any adverse effect on aluminum ?

EdStainless (Materials) · Answer 5 · 2016-04-28 12:56:07

Yes, do not embed Al into concrete. As you get corrosion you will get spalling of the concrete next to the Al.
If you go with steel for this you also need to be careful. The steel in the concrete will be fine, but where the steel and Al meet there is also a chance for corrosion. Normally there are isolation kits used (washers and bushings) to prevent the two metals from touching.

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Does concrete corrode aluminum ?