[jgray152]

Has anyone ever attempted to use pea stone crushed granite with concrete to make a faux granite step or walkway?

I am in the process of making some samples for practice and so far I am running into a few issues.

1. The portland cement is grey not white or light grey so the cement voids around the crushed granite makes it all look to dark and unnatural. Adding some Tera Cotta integral color helps a little to remove the grey but its still dark.
2. Need a very high granite to cement ratio. Not sure what this will do for durability.
3. I need to grind the cream of the surface to expose the granite. This is very time consuming. I have tried rinsing the cream just before its cured but this does not create the effect I am looking for and causes some granite to be loose.
4. After adding calcium to the portland it still takes so damn long to cure!

I add calcium to the water before putting it in the cement since its not a powder, its small flakes, does this reduce its effect on the portland? I never have to use portland alone so this is a semi new area. The only time I use portland cement is for Fiber Reinforced Concrete which is different. I use Acryl60 at that point and it cures much faster but acryl60 is expensive.

 

[jgray152]

The matrix (concrete) is very much softer than the aggregate (granite), so it will either pull out or be nearly impossible to grind smooth.

I personally have no problem grinding granite. It seems to ginde away and smooth out with the cured concrete just fine. The time consuming part is doing it with a 4.5" grinder.

How do you add "calcium"? Are you just adding milk or something with a different chemical composition. What kind of a mix and type of curing are you using?

Well here is the thing and the reason why I am using calcium. When I order concrete from the plant, it will set up very quickly, usually within 1 hour its pretty well setup. When making my own mix with portland and sand/aggregate, it takes 5-6 hours for it to even remotely get hard. This is the reason I am using calcium which it seems I am not using enough of it because it still takes to damn long to set up.

Concrete is not for amateur kitchen chemists. Acryl 60 is not expensive if you consider you are working with it for something that is meant for a different purpose.

The "milk" or "Acryl60 I am not using unless I am making Fiber reinforced concrete. The Acryl60 helps the curing process when needing this type of application but the Acryl60 compared to a bag of calcium is more expensive. Also, I do not like using Acryl60 when using acid stains because the stains sometimes will not work to well. At least the ones I use.

For a (gray) granite appearing product, consider using lightweight aggregate and/or coal slag along with white portland. Broadcast and work the aggregate in, then grind it.

I'll keep this in mind. Thank you.

 

[jgray152]

Well this is a crappy picture but here is a sample with the granite in the concrete. You really can't see the granite to well in this picture. I'll have to use our other camera when I find it. That top stone is sealed with an acrylic sealer. Really brings out the beauty of the concrete

I made another sample the size of a brick but I really loaded it with granite and very little cement, I also colored the cement terra cotta but after grinding it, after adding a lot more granite, it still doesn't look how I want. Basically the granite pieces are just spaced to far apart. If I want to do this I may have to find a way to get the granite closer together. Maybe finding a small crushed granite pea stone.

It takes very little money to do this so if I can perfect it this could be a cost efficient way of making granite steps without spending over $100 for one step. Instead I could make it for less than $20-30.

Doing this on an entire walkway would be time consuming and a lil more expensive I think because I would have to rent a machine to grind the surface of the walkway to expose the granite.

Winter is coming so I will put the sample outside to see how well it does through freeze and thaw cycles. Maybe with some salt in on area, Although this is not air entrained so even if it did flake it really won't tell me anything.

 

[jgray152]

If I could get it to look like that, that would be great. When you say broadcast, you mean spread over the wet concrete and worked into the surface a little?

This is my beginner version so far.

Here are close up shots of the larger sample.

Not Sealed. Not ground as smooth as the image below this one.

Sealed

 

[jgray152]

:clap::thumbup::w00t:

Excited to see results!

I'll pick up some coal slag and some point. I'll have to find out where to get marble dust from.

 

[jgray152]

Hey jgray (and TS), Have you tried an acid stain? Seems like it would stain the cement, and leave the granite unaffected...maybe..

I have thought about that. I have a few colors, nothing really light. I do have greenish color, I wonder how that would look. The next colors I have is black (really dark dark red) and dark walnut (turns gold, copper or brown, lol)

 

[jgray152]

Good work tscar. Looks better than mine. I wonder if using larger coal slag would look better?

 

[jgray152]

Looks Great! I like the very small black particles. Maybe more of the white marble but I like it a lot.

Now here is a question, if this gets wet can you get coal "dust" on your fingers? Say you make a step from this and you don't seal it at all, it rains and you walk on it bare foot, will you pick up black traces of the coal slag?

Also, what did you use to grind it? I Don't see swirl marks at all. I use cheap resin blades or diamond blades which produce swirl marks. I use the resin blades to reduce the swirl marks.

 

[jgray152]

If you have a source for expanded clay or shale, try to find an uncrushed natural fines aggregate (rounded) that is clean or could be washed more for casting. It is tough to find to find and is costly, but the amount needed is really pretty small and not a major cost factor, and the use can be learned.

I have found this at the plants from the old (epanded rotary kiln shale ot clay) Arkalite and Gravelite plants near West Baton Rouge, LA and West Memphis, AR (now probably Olcastle plants now) a number of years ago. Very good, but saturate it in water for a day or two before using because the absorption is very low and very sloooow. It is rounded, so it can pull out easily, but is great when bonded into the matrix before grinding.

Use this replacing the coal slag?

 

[jgray152]

Oh ok I thought coal slag was a form of coal. Shows how much I know in this specific area

Orbital sander, I will have to get my hands on one of those.:thumbsup:

 

[jgray152]

I just noticed there is a "concrete" section. I missed that when I was originally posting on this forum. Sorry guys.

 

[jgray152]

ooooooo, I like that! Especially if the matrix has a slight blue tint to it.

I don't know if you like it but.....I love it. Unless its just the picture, does it look that good in person?

 

[jgray152]

aas it a light dosing of LWT

aas? lwt?

 

[jgray152]

Up to 3/8" from the old TXI plant. The stuff they provide for the CMU is a very good aggregate. This stuff is junk they put in the concrete, basically.

Edit- For the concrete it works fine, but it is not meant to be ground.

That was a confusing post :sad:

The expanded shell was junk they put in the concrete and its not meant to be ground?

 

[jgray152]

Yes. I know the owner personally. He lives about 40 minutes away from me. I met him a while back and I worked with him and he trained me on some of the stuff I do now. He has some videos on Youtube and I am in a few of them. I had long hair then. Videos are Retainer Walls, Water Features and StoneMakers Opportunity.

In fact, if you go to my website, http://www.innovationlandscaping.com and go to the hardscape menu, click on faux rock walls, there is a link you can click for one of the videos. Then if you go to the water features menu and go to FauxCrete Water Features, there is a link there you can click on for another video.

Today I am hoping to meet up with him since he owes me some money for a job I did for him.

 

[jgray152]

Wow Thanks for the information folks! :thumbup:

Once the warmer weather comes around I will start up on this again.