What should be done to stop this from spreading and opening up more? Or am I trying to close the barn door after the horse is already out? What can be done to avoid it happening?
The slab was poured last October. It is in northeastern Ohio- we didn’t have any freeze on either side of the pour for at least a week.
It is fibracrete poured 4″ thick over 6″ clean compacted stone. The slab was sealed to prevent curing to quickly and control joints were sawn the day after placement.
Probably 98% of the pour is fine with this one area of concern.
Two pics- one of the cracks and one to show size of the pour.
Thanks for your help.
Replies
Two more pics- day of the pour.
the cracks are center of the slab adjacent to the second pier in.
you can't really see but there is expansion joint between the slab and the piers and also slab and house.
control joint cut deep
hi BB,you mean cut a deep control joint thru or near the crack to keep it from spreading?No Tag
yes
okay.thanksNo Tag
""the cracks are center of the slab adjacent to the second pier in.""
Are you describing the location of cracks as being on the porch between the house and the pier?
Confusing to me whether the crack is on the walk way slab or the porch slab.
""you can't really see but there is expansion joint between the slab and the piers and also slab and house""
Is there a control joint from the corner of the house to the pier?
They can't get your Goat if you don't tell them where it is hidden.
Yes the crack is between the pier and the house and there is a control joint cut from the pier to maybe not the exact corner of the house but within a few inches of it.Now that I think about it the crack runs roughly perpendicular to the control joint and extends on each side of it. So was the joint not cut deep enough?No Tag
Quite possible. But, every outside corner of the pier or the house is a crack generator. That is the reason you see a diamond cut around posts and from each corner of the diamond the control cuts then are cut, or a circular joint is cut/formed around the base of a column and the control joints then pulled off the circle. It is also possible a control joint was tooled in , then filled and retooled in a slightly different location , but within inches of the original one. Often if this occurs a crack will develop along the line of the original tooled joint because the aggregate has forced aside there and the "fill" is nothing but cream.
They can't get your Goat if you don't tell them where it is hidden.
pretty sure nothing was tooled in. I was on site all day of the pour and don't remember seeing anyone tooling joints- just edging and rubbing faces.At any rate, the guys that did the pour are going out first of the week.Now I know a little more about what they should be telling me.ThanksNo Tag
Well, I have very similar cracks in my concrete pool deck , I believe it to be caused by a lack of strategically located and spaced control joints. I've been looking at these products to heal the cracks. A concrete finishing guy suggested that the concrete be saw cut after the repair to allow any new cracking to happen in a controlled manner. Hope this helps, I've been going through the same grief!
http://www.concretemender.com/
http://www.emecole.com/driveways_patios_pool-decks.htm
that is good information- thanksNo Tag
Any idea what the slump was?
I hired the reputed best for my house, he was a fan of high slump and calcium chloride. Mud self-leveled. It's flat, and the only slab up here full of cracks like yours. Some took awhile to develop.
The other slabs I poured, not particularly flat but immensley fewer cracks. Low slump, we worked.PAHS works. Bury it.
Five I think. Still have the tickets so I will check.Concrete yard is only seven miles from the site and I remember glancing thru the tickets and being satisfied with time on time off- amount of water added- and seems like slump was five...No Tag
you can place concrete will out cracking, I can do it and guarentee that it will not crack, but. it starts with the sub base, form , mix etc, it take detail. and if you have one person in your crew that doesnt care, forget it, it will crack. the people that say "All concrete will crack are those that dont care"
fair enough.educate me...No Tag
I thought all concrete came w/ 3 guarantees. Fire proof, theft proof and guaranteed to crack.
Seriously though I would think the more control joints you have the less cracks you're gonna see.
Not sure how to fix this now. Sorry
Dave
Yeah- my contract spells out concrete can not be warranted against cracking.There are control joints cut every 12' or so and coming out from any corners where you might expect to see cracks develop.This is just out in the middle of nowhere so to speak.No Tag
Imagine concrete as crystal growing. If you pour one chunk, then wait for the next truck load, the two sections will never grow together. If you have a long section of sidewalk, one part in the shade, the other in sun, the 2 section will not grow together (crack). I have seen cracks follow rebar that was maybe not deep enough, but I think it was because the rebar was heated by the sun, which changed the crystal growing at the rebar. Deep joints limit the growing of crystal chunks. Poured concrete in columns and sonotubes dont have cracks because the weight forces the crystal together. Tamping of wet concrete, when done right, restarts the crystals forming into one piece. An "L" shaped slab will always in it corner cause it separate crystals.