I've just used the standard Portland whatever.  I think it was #3, I found it successful, but just not that attractive. 

Adam

I should have mentioned, I used crushed coral almost exclusively.

Adam

I would recommend the white portland cement.  I looks better and only requires a fraction of the curing time of standard portland.

Let me know if you have any more questions.

Great suggestions everyone thanks, BTW actually all portland cements require approx. the same cure time it just depends on amount of water used, temp., and consolidation method. Type III gains early strength the fastest but as adam said it's not pretty, sort of a clay brown, Type I is the white and doesn't gain as much strength in the long run as II or III but is much better in architectural applications, which is essentially what I'm doing so that should work. I was concerned about the higher amounts of alkali in type I white but it sounds like it works just fine.

The plastic shavings sound good, and I have an abundance under my table saw at the moment thanks to a remodel I just finished who wanted a lot of flex trim, so I'm good there. I do have cheerios (thanks mark), and aragonite sand, I'll pick up a bag of crushed coral at F4U on my way home today and the cement at HD on my way to work. So I guess tonight is experimentin' time thanks guys I'll post some pictures and info on my results.

When I say curing I mean time until it no longer leaches out a high pH at a fast rate.  Not time to solidify to full strength.

Gotcha, sorry I used to mix concrete ALOT, but I understand now. BTW
(concrete nerdness again) concrete theoretically never reaches it's full strength, It continues to harden as long as there's available moisture for the cement to bond with. 96 year old footings have been broken apart and still had curing (hardening) occuring in the centers of the members.

My fish geek isn't quite up to par yet so I have to throw out cement geek whenever the chance comes up.

Jake, what's the best way to cure (your meaning) fresh aragocrete, saltwater soak in a bucket, or would fresh work better due to lower pH?

As Mark said.  Freshwater.

If you continue to see a high pH after a week or two you can always add some vinegar (or other acid) to help the process along.

Also as Mark said, I would check out GARF's web site.  You should find some good information there.

That made sense to me too...

Ok, just skimmed every article on the GARF site about the stuff, some great info for sure. As for the mix ratios listed in most of the articles they seem a little light on the larger side of the aggregate grading. I guess these are just rocks though and not I-15 bridge beams, But I'm gonna try that mix ratio anyway and see if I can make indestructible aragocrete .

Let us know how it turns out

jfinch wrote: For curing, how 'bout driving up the canyon and dropping them in the creek at some secluded location.  Come back in a month and get them.  I would think they would cure faster with a constant flow of make-up water.

That is exactly what many many people do.  Including GARF of course.

Adam

Works great as long as no pollutants/VOC's are dumped upstream as happened to me!

Well, I wasn't suggesting the Jordan River .

I was going to post a question about curing in a river or something last time I checked in this morning. I come back to find a wealth or responses to a question I never asked.

<<<<<<<<<< a little freaked out right now.

Ok, after a few trials I think I've stumbled upon a great mix that produces VERY pourous rocks with NO additional materials. I just cast some GARF style egg carton plugs with it yesterday and these things are light and holier (not blessed) than any live rock I've seen yet. Here's the rundown:

Mix (by volume):

1 part cement (portland type I/II will give the best strength)

3 parts aragonite sand

2 parts coarse crushed coral 1/8" - 1/4" nominal size (I used Caribsea Florida)

VERY little water (this is important)

The key to high strength, well made concrete has always been saturated aggregate (sand and gravel). It's important that your materials be saturated-surface dry, no excess moisture but no absorption either. To acheive this, wet your materials (minus cement) a while in advance making sure not to add too much water, stir to ensure even absorption and allow time to saturate. If after a few hours you have free water, pour it off and add some dry sand till it's not shiny at all.

Once you have this, go ahead and mix with cement first to coat and then add the very little water 1/3 part by volume should do it. you want it to be super dry, think oatmeal haystacks, the idea is to add only enough water to hydrate the cement. If your aggregate is dry when you do this it will suck the water out of the cement and weaken it too much.

Now go ahead and mold your pieces in whatever form you've chosen making sure that if the mold is absorbent that it is presatisfied as well. once cast it will seem to be less than solid and you will want to rod or pack it, don't. Simply vibrate the form slightly to ensure contact between the cement coated particles and cover to avoid dehydrating.

Sorry this has been so verbose, I hope somebody still finds it worthwhile and reads the whole thing. If anyone is interested and wants to try it let me know how it goes, or if you want to see some of the finished product contact me.

Got it, thanks Mark. Actually it turns out so pourous because rather than the hydrated cement filling the voids between the coarse aggregates it meerly coats them and bonds them together. Like Rice Crispy treats. So rather than enclosed air pockets there are actual tunnels all through it. I'll see if I can post a pic but I doubt that would really give you an idea of the nature of the pieces. I'll bring some to the next meeting and perhaps could throw in a quick demo when the DIY meet rolls around. Or if you or anyone for that matter would like to come by you're all always welcome.

Mark Peterson wrote: Yes, I've been hoping to call to see if you wouldn't mind a visit. And after seeing the pics of your pond, I'm even more interested.

Where are there pics of your pond?  I am building a 2,000 gal w/waterfall and am interested in seeing yours before I get going on mine in May.