Aluminum window screen as wire mesh be for strengthening concrete?

Question

I am making a 2” slab of concrete for DIY 45 lb weight plate.

I have some extra aluminum window screen that I’m not using. I was thinking of putting some strips of window screen into the concrete midway to make it stronger.

You think this is a good idea?

I would “just try it out” but I don’t have a backyard to do many trials of concrete and am going to have to do this when I find the time and place.

Go to an actual masonry supplier, or the internet, as I don't think you'll find these at a big box, and get a bag of reinforcing fibers for concrete. As noted by MTA, aluminum will destroy your concrete, not reinforce it. — Ecnerwal, Feb 15 '23 at 03:39
OP could look at fiberglass mesh, I've seen it used successfully for reinforcing things like countertops. — nathancahill, Feb 17 '23 at 09:15

score 54 · Answer 1 · answered Feb 14 '23 at 22:51

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Aluminum is attacked by the alkali in concrete. The reaction gives off hydrogen gas.

There is a research paper, Corrosion of Embedded Material Other Than Reinforcing Steel (PDF) published by the R&D Labs of the Portland Cement Association. It includes reports of failure and spalling of concrete from embedded aluminum.

Not a good idea!

answered Feb 14 '23 at 22:51

MTA

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Also: https://www.concreteconstruction.net/how-to/concrete-production-precast/how-does-contact-with-aluminum-affect-concrete_o In short, it's at least as bad or worse for the concrete as it is for the screen. – Ecnerwal Feb 15 '23 at 01:29
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And in any event, the tensile strength of even uncorroded aluminium is so far below that of steel rebar or mesh to make it ineffective. – Mark Morgan Lloyd Feb 15 '23 at 09:12
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And Aluminum expands twice as much with temperature as concrete and steel. The concrete/steel combination works well because they expand in sync so that they can stay firmly connected. – Peter - Reinstate Monica Feb 15 '23 at 18:27

score 36 · Accepted Answer · answered Feb 14 '23 at 22:21

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I don't think so. Screen will almost act like a divider in the concrete. You won't get good aggregate pass-through. Even if you agitate the mix enough to get the loose cement through, you're essentially creating planes with no strengthening aggregate in them. You're almost better off with no reinforcement.

That's just my edjumacated hunch, though.

answered Feb 14 '23 at 22:21

isherwood

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He's certainly better off with no reinforcement, not "almost". A very fine mesh is going to have about as much adhesion to the surrounding cement as a sheet of paper would. As you say, it will block any aggregate from passing through and create a massive shear weakness. And if any water ever gets in there (it will), the concrete will spall right off the mesh. – TooTea Feb 16 '23 at 08:44
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Moreover, the thermal expansion of aluminum is very different from the concrete. So it will create stress (which will lead to cracks),when the temperature change. It doesn't happen for reinforced concrete because steel happens to have a similar expansion coefficient as concrete (luckily). – dim Feb 16 '23 at 12:53

score 4 · Answer 3 · answered Feb 14 '23 at 22:24

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That type of mesh is never used for strengthening concrete. I believe the only think you will accomplish by adding that mesh is divesting yourself of the mesh.

answered Feb 14 '23 at 22:24

RMDman

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Aluminum window screen as wire mesh be for strengthening concrete?

3 Answers3