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Can decomposed granite be mixed with cement for use as structural concrete? Answered

We have a mountainous property with no sand and very little rock other than granite. Can I use decomposed granite (as fine as sand and small pebbles) as aggregate, instead of river gravel and or sand?


Thanks for the responses. I guess there is a reason you only see deco on tennis courts, driveways and paths. Looks like I'll be hauling rock. Nice pun Joe.

I think the proof is going to be in the finished product.

What I am suggesting is: You mix up some sample blocks. Then let them cure. Then test the strength of the finished blocks.

I do not know where, to whom, you'd go for professional help for this sort of thing.

This site:


came up near the top in a Google(r) search for "concrete testing"

IIRC Frank Lloyd-Wright used decomposed granite concrete for the blocks of the Gehry house in LA, and some blocks at Southern Florida College....it didn't go well.

So I guess that rock is OK aggregate, but you really don't want to take it for granite.

Heh... Take it for granite. It's a pun. ;-P

+1 His River House had to be saved with support posts

One might say he overextended his reach :)

Someone with Guts or a Huge Ego had to try these ideas, after all, we learn more from our failures then from success... That's why we push working designs harder and harder, to find a failure to learn from....


It is OK for walk ways and drive ways only.

Use it for things like a bridge wall or a foundation and it will not last.

Does not matter really what use as an aggregate as long as it is strong enough - and I guess granity qualifies for strong ;)
People use paper, saw dust, sand, polystyrene and more, so using what you have at ahnd just seems like logic to me.