Concrete Mixture Question

[rodeair]

I am trying to decide on a concrete mixture for a decorative band which separates the different levels of the enclosure. I'll be forming one pour on top of the cinderblock, then using metal framing from the top of the band up to the top of the enclosure. Manufactured stone will be veneered to the enclosure. I made 2 test forms for the pour I want to do. The first was bagged concrete, the second was 3/4 part portland, 1 part sand, 2 parts vermiculite. The concrete one weighed 34 lbs., the other 22.5 lbs. Does anyone know if it's worth it to do the lightweight concrete given the metal framing and the upper enclosure weight will be sitting on it?

[azatty]

Re: Concrete Mixture Question

Are you going to veneer over the band? If so, why bother with it? If not, it's a question of aesthetics--which looks better to you?

If weight is the concern, how about modifying your form to make the casting a "donut" rather than a solid? Maybe throw in some reinforcing needles or fiberglass strands if you're worried about how it will hold up. The steel stud bottom plate can span a 6 or 8 inch hole. Just support it where the plate anchors and vertical studs are located by filling the cavity with concrete (you have to do that anyway). That'll drop a bunch of weight; the casting probably won't weigh more than the cinder block.

[Neil2]

Re: Concrete Mixture Question

I would avoid a vermiculite/cement mix in any exposed area. It is subject to damage and is not water resistant at all.

[rodeair]

Re: Concrete Mixture Question

Thanks for the suggestions. The picture below is the look I'm going for. The decorative band at the top is the one I'm concerned of, as far as weight I suppose regular concrete is the way to go. Thanks again for the replies.
Leigh