How to smooth rough concrete?

[Pilot]

When we built the house 21 years ago, I wanted the outside concrete areas to have a rough (brushed) surface to minimize slipping when frosty.

Times have changed and in one area we want to put up a dog run. I would like a smooth finish in that area, but it has a brushed finish.

How can we smooth it out? Can it be done?

 

[CalG]

rent a power trowel

clamp some concrete half blocks to the blades.

Cover the area you want smooth in sharp mason's sand (sparse)

hose it all down, and keep the water running.

Apply trowel until satisfied!

 

[jinman]

CalG, it sounds like your solution is top-down rather than bottom-up. I think I agree with you. Wet rolling abrasive and abrasive stones on the power trowel should do a great job, but "clamping" may not be as simple as it sounds. I'm not sure how you would accomplish this.

 

[LD1]

You can rent a concrete grinder. Kinda like a floor buffer/polisher but made to grind concrete...

 

[Gary Fowler]

CalG, it sounds like your solution is top-down rather than bottom-up. I think I agree with you. Wet rolling abrasive and abrasive stones on the power trowel should do a great job, but "clamping" may not be as simple as it sounds. I'm not sure how you would accomplish this.

I think that the concrete blocks CalG mentioned are available specifically to fit a power trowel. I seem to recall seeing them used on a jobsite once to smooth some concrete. It isn't a fast process but with just removing the brushed finish, it shouldn't take long at all.
The concrete grinder with the diamond cutters is probably overkill for the amount of work that you need to do.
Personally I think a brushed finish is would work fine in a dog run. Unless it is a heavy brushed surface it should wash down fine, but the power trowel with abrasive stones would do the job pretty quickly.

 

[paulharvey]

Depending on your budget, you could
A: crawl the slab, rubbing with a Concrete block, it will rub the broom finish down
B: power trowel, throw sand on slab and trowel away
C: spray with muratic acid and use a push broom
D: "stucco" it, spray,brush, or roll on bonding agent, mix up a sand-portland mix, smooth trowel that on
E: recap with ~2" of "self leveling concrete" you'll need to do some form work for this

Basically none of these methods will yield a nice burnt finish. So, you may want to look into something more like "cool deck" plaster, or perhaps an exteteior tile.

 

[SSdoxie]

Be careful in getting it too smooth. Moisture on smooth concrete makes for hazardous walking, just going into feed them, let alone washing it down.
You should apply concrete sealer (2 - 3 coats), whether it is left as brushed finish or smooth. Dogging-do sticks to concrete either way after they do their job and walk on it. I have 2 concrete runs, first one was converted from an old garage approach and the second one I built specifically for it. Both have brushed finish with 3 coats of sealer. A garden hose with a cone nozzle will clean it just fine.
My Brother-in-law built a run. He did a smooth finish on the concrete without sealer to start, had trouble getting the stuck stuff to hose off easily so applied a sealer to it. Then it became hazardous to walk on whenever humidity was high or just after he cleaned it.

Depending on how rough a finish it has, you might try apply sealer first. See how hard it is too clean, if too difficult then grind it down and reseal it.

 

[jinman]

I think that the concrete blocks CalG mentioned are available specifically to fit a power trowel.

If so, they probably have them at the rental yard, maybe even in different grits. That would just make it too easy.