floor just poured and is cracked

[308turbo]

located in south carolina. dug down to get to untouched soil. used packer then put 4inch of 57 stone used packer again.. Its a monolithic slab footers are 12 by 18 around the whole outside 30x36 with a 4-5inch slab...Concrete guy cut relief cuts in it but i am wondering if they were not deep enough??...i back my pickup onto it today and then notice about 2 feet over from the relief cut there is a crack from the edge where the door is about 8 feet long slab has been poured for about 2 months its fiber mess concrete..

thoughts?? i am just about to start framing and now im not sure what to do or what my options are? trying to get a picture uploaded

 

[deter]

what reinforcement is in the slab? some small shrinkage cracks are nothing to worry about

 

[308turbo]

2 rows of rebar around footers....have 2 slabs built almost the same way at work but it 6inch thick with no problems...maybe im over reacting about it..I think its because maybe it didnt go deep enough with his relief cuts??

 

[Rookie2]

I cut 1 " relief cuts and soon after the slab cracked at the cuts.

 

[cj7365]

how deep are the control joints? how wide are the cracks? pictures???

 

[308turbo]

 

[308turbo]

not sure how deep the cuts are,will have o try to find out tomorrow..Is there rule of thumb on how deep the cuts should be?

 

[383]

They should be 1/4 the thickness of the slab.

Concrete is gonna crack, and sometimes it's not going to follow the cuts. That is why we put rebar in everything, if it cracks, at least the pieces won't separate.

 

[Wangstang]

What's up with the unfinished edge below your forearm? Is this an entrance ramp or the main slab?

Wes

 

[ConCretin]

308turbo, It sounds like you did a good job preparing the the base so the crack is probably not structural. I'd have been more confident if you had installed rebar throughout but the bars around the perimeter haunch should hold things together and keep the crack from opening up.

Think of it this way, if the sawcut joints had worked properly, you'd still have the same crack. You just wouldn't have to look at it. Probably nothing to be done for it now. I'd just go ahead and finish your garage.

 

[ddawg16]

One thing I've been told about concrete and saw cuts....concrete expands and contracts the same in both directions. So cuts need to be in the proper position...

Say your pouring a 10' wide drive way...then your cuts need to be every 10'.

As one guy put it....concrete likes to be in squares.

 

[ez-duzit]

2 rows of rebar around footers...

There's your problem. The slab is supposed to have reinforcing mesh embedded.

 

[308turbo]

One thing I've been told about concrete and saw cuts....concrete expands and contracts the same in both directions. So cuts need to be in the proper position...

Say your pouring a 10' wide drive way...then your cuts need to be every 10'.

As one guy put it....concrete likes to be in squares.

ya he made squares out of it when he cut releif joints

 

[Bruce4310TX]

fiber wont hold it together............only re-bar, fiber it a waste of good money

 

[deter]

2 rows of rebar around footers....have 2 slabs built almost the same way at work but it 6inch thick with no problems...maybe im over reacting about it..I think its because maybe it didnt go deep enough with his relief cuts??

if the slab itself doesnt have reinforcement in it, then you should expect cracking.