Help with concrete!

[Alexander Galkin]

I have never before worked with concrete so I apologize if I am asking silly questions. But I really need help. I poured today concrete to fill trenches I made in my basement concrete floor for under slab plumbing. I used QUICKRETE general mix that I bought in HomeDepot. I followed manufacture instructions and added 2/4 gal water to 80 lb concrete mix and thoroughly mixed them. Finally I got sandy paste that I poured into trenches (I backfilled trenches with gravel 4" below floor level so new concrete should be the same thickness of 4" as my existing concrete floor) and leveled concrete with existing floor level using steel trowel. Now what do I do next? Do I just let the concrete dry (for how long?) and that's it? And most important question: how do I make concrete mirror like smooth as my existing concrete floor? Since concrete mix with added water is actually like sandy paste I don't expect it to be smooth when it is completely dry?

[Colbyt]

This may be too late to help you and I am far from a concrete pro, so I defer to any who post.

You dump the concrete in the hole and float it down to level with a mag float ( a scrap of 2 x 4 will work for a one time project. Pat it gently to settle the rocks a bit and bring the batter to the surface. Leave it alone until the surface goes dull, work the surface with your steel trowel, now you are settling the sand like you did the rocks earlier. Water rises and it gets wet again. Leave it alone until it dulls and repeat the process. And maybe another time or 2 until it as smooth as you want it.

If yours dried before you got the response you may be able to use a slurry mix of Portland cement and water to retro the steel trowel part. You can save the extra Portland for you next project, I always like to enrich the bagged quickcrete just a bit with a shovel of Portland per bag for anything other than fence posts.

[Joe Bobst]

That's a neat idea. The bag stuff is always on the low side for strength anyway and the portland ought to make it finish better. Wonder if a dab of lime would hurt...

Joe