Concrete Popping While Troweling

house bldr

recently while power troweling a garage floor I had a spot about 16" around that started to pop loose as I was hitting it the last time with the trowel.Just about the top 1/8" or so.This is the second time in a month or so this has happened.Last time was a basement floor.One was a 5-1/2 sack mix the other a 6 sack.I have never had this happen before.It acts like maybe to much cream like it was over troweled but I don,t think so, the rest of the floor looked fine.Maybe just bad luck with an unmixed clump? Twice?Any ideas or suggestions? Thanx!

hatchet

If it was wet underneath the area - most likely it was troweled too early. If it was dry underneath - go back and check the entrained air content. Also if you pumped it - that will naturally increase the entrained air. And most likely fly ash was added - that can harden the surface too quickly and cause popping in areas.

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Rich
WIT Construction Co.
Superior MT Contractor

joasis

I have had that happen many times...and the blame usually falls to the truck...and poor mixing....but since it can be several things, it would be hard to say without being on site. I know many of the additives our local ready mix uses can cause all kinds of fun..that, combined with worn out mixers and clumping cement (unmixed) really make a day of it. However, it has happened to us with a plant that uses no fly ash also...and promise no special additives...

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house bldr

The concrete did have air, I believe about 6%. I have heard you shouldn't trowel concrete with air but we do it often and haven't had much trouble.By code outside concrete must have air in my area, how is a guy to finish areas such as porchs if you aren,t suppose to trowel air entrained concrete? Any tricks?

joasis

Use a fresno finish...keep the power trowel off

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