fresh concrete slab caught in hard rain

[mbed]

i recently had a basement slab poured for our new home as contractor was finishing it rained very hard for about 40 min.the slab is 2300 sq ft and has 5 " of gravel,1" polystyrene foam,radiant floor barrier,10 guage remesh, radiant heat tubing and fiber mesh added to concrete.slab is app 4.5" thick and leading edge at walkout basement wall is app 10" thick.he did not cover slab and a lot of the top layer was washed away.he then added portland cement to floor and flinshed it as best as he could.we had plans to acid stain floor and now it has power trowel marks ,several dark areas (i think this is the portland) and finish is uneven and not as smooth as concrete i have had poured in past.is this floor sound enough for our house?can it still be stained? should i have concrete tested and what test should i have done? i'm i need of professsional advice as i dont know what to do from here.thanks mbed

 

[BigH]

Applying a thin portland cement 'slush' to a slab is very inappropriate - and WRONG. Most specifications say something to the effect that: Sprinkling of the surface with dry cement and/or water during finishing to facilitate troweling or any other purpose will not be permitted. I'd say to the contractor - TAKE IT OUT! He should have been prepared for the rain - and it seems that his crew is not experienced or just didn't care.

 

[Ron]

Agree with BigH...using a neat cement paste in an attempt to restore the surface does not work long term. If you do a compressive strength test on the slab it will likely pass that test; however, that test does not cover the long term durability of the concrete, which is often more important than basic strength.

Have the contractor remove the slab and place the next one properly.

 

[TXStructural]

If you can spare the elevation, have a replacement slab placed on top and finished properly. You probably only need a couple of inches of concrete, with our without reinforcement. This will act as the finished floor and the current slab will provide support and structure. I would be concerned that the existing slab with cement paste on top will delaminate or have excessive cracking, if not now then soon.

 

[madmantrapper]

I would add a couple inches to the top also. Have done this in the past without a problem that I know of. The top layer of the existing is definitely going come apart. Also will be a dust problem unless sealed with a thick sealer.

 

[darthsoilsguy2]

pics

 

[BigH]

Doesn't any fear that, unless the poor slab is scabbled to more durable concrete, that a thin lamination over a poor surface will also run into problems down the line?

 

[Ron]

BigH...you are correct. I usually require removal of at least to the depth of the nominal coarse aggregate size to make sure you are back to sound material before putting a topping on (that's assuming we are considering a bonded topping....I'm not a fan of unbounded toppings, which is what you'll get if you place a topping on an unprepared slab....or worse...you'll get partial bonding which will increase the "randomness" of cracking.)