# SANDBLASTING CONCRETE



## greens1 (Mar 31, 2001)

Hi,

I was wondering if sandblasting driveway slabs, to make the concrete look like new, was a good idea. Are there any negitive effects on the concrete from this process.

Thanks,
Jim L


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## WALT (Feb 7, 2001)

*Get a good pressure washer*

Greens1,
2 negitive thing I see about that is, the mess that you will make in that area, and actually damaging, peeling or pitting that surface layer, becase of it abrasiveness. I seen sandblasting done to steel concrete forms to get that build up of paste and crap off of them, and it pitted the steel forms. Just think thats a little to harsh.
Suggest renting a hi quality presure washer, and use a good de-greaser cleaner to go with it, that would do a good job. Some people contract this out to a company that specialize in this sort of work (pressure washing). But think you can do it just as well with the right equipment.
It will never look like new again but you can make it closer like this, the new concrete will match up to the old easier and sooner than trying to get that old to match the new. 
Just a suggestion, if you decide to sandblast please post the results, I am very curious to see if this works. I myself have never heard this done to achieve like new concrete, have you? Good Luck and hope this helped...


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## greens1 (Mar 31, 2001)

Thanks for the advice Walt. I believe I will take your advice and go with a high powered pressure washer, possibly heated w/chem feed. To be honest I have never heard of sandblasting a drive but this customer is pickey and wanted me to look into the possibility of sandblasting, I think he saw it done to a house to remove whitewash from face brick. If, after powerwashing he still insists on going with sandblasting, I will have him sign a waiver of liability, I will be shure and post the results.

Thanks,
Jim L


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## guido (May 13, 2001)

*Etching*

When you "sandblast" the concrete I think you mean to be talking about chemical etching. Sandblasting is not recomended for outdoor use because it chips away at the surface of the concrete, which will let water get deeper into the cracks and you open it up worse for chemicals such as salt, etc to penetrate the cement and break out the aggregate in the crete.

The heat shouldn't make a difference on this application as far as the pressure washer goes.

[Edited by guido on 04-22-2001 at 03:11 PM]


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## Lanelle (Feb 16, 2000)

I agree that sandblasting is risky business and the results could be awful. How about a nice paver driveway?


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## Rob (May 15, 2001)

It seems like you already made up your mind, but my .02 is to go with the pressure washer idea. I pressure washed my house last fall, and in the process tried the washer on my cement steps / small porch in the front and back of the house. The results were great. While the cement doesn't look brand new it did restore cement that was close to 50 years old to something that looks good. I did not use any chemicals in the water, not even the house wash. I just used the "medium" tip so as not to score the cement and had no problems.

Good luck with the project,


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## jason2 (Dec 22, 1999)

This is probably not relevant to driveways, but I'll post anyways. 

I used to work at a precast company. We made architechtual concrete pieces. There were a few different finishes we used depending on what the customer wanted. One of them was a sandblasted finish.

After a piece was poured and cured we would then lightly sandblast it. It gave the piece a beautiful sandy appearance. 

You have to be very careful not to sandblast to much or you will erode the concrete and make a rough finish. Also if the mud wasn't vibrated enough, air pockets would form. Sandblasting would open up these air pockets and leave nasty looking holes, which we would have to patch. If the holes were bad enough we would scrap the piece and pour another.

I don't think blasting a driveway will give you the results you are after. It will give the surface a grainy appearance. And you must be extremely careful. You never know if the driveway was even vibrated, you may open up a bunch of air pockets.


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## greens1 (Mar 31, 2001)

Just wanted to say thanks for all the posts. I believe you guys saved me a great deal of time and headachs. I don't think this customer would have been happy with sandblasting. I rented a 3500 psi pressure washer, tow behind, heated with a chemical feed and it worked great. The concrete doesn't look quite new, but it's close.

Thanks for all your help,
Jim L


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