Delamination on new pour

[Flatblackratrod]

Hello folks first post and it is an unfortunate topic. I recently started my build after lurking on these forums for quite some time. You can read the long story below but the short story is my new pour immediately started to delaminate and I am looking for the best option moving forward.

-contracor immediately wanted to tearout the bad portion of the slab (approx 3/4 of it) cut it away from the footings tearoint and repour but is going back and forth with the redimix company to try to get them to cover materials for the repour. Contractor is willing to eat the labor. My biggest concern here is I feel having several different pours gives me opportunity for things to heave and move around separate from one another. This is a 5" thick slab that was poured monolithic style with 42" deep footings. The contractor says he will drill and epoxy the rebar into the footings and the portion of the slab he leaves.

-As a secondary option the contractor suggested grinding and polishing as the concrete is structurally sound under the finish. I really liked that option but he has since back pedaled and no longer feels comfortable offering that as an option.

-epoxy is pretty far out of the budget right now but it was also suggested as a fix. It is something I thought about for a future option but with the prices I have gotten it would need to be a diy option

-grinding and a self leveling topper was suggested as an option but material cost and labor would likely be entirely up to me I was quoted 2500ish in just topping materials not including grinding.

Full slightly more detailed story below:

I had my slab poured "monolithic" with footings 42" below grade to reach frost depth for my 36'x40' garage. Everything went seemingly well untill the finish. My concrete contractor poured on a Friday night and finished up late and said he would be back out first thing Saturday to cut my relief cuts. No problem... everything looked great on Friday night. Saturday rolls around and he follows through on his end of things shows up and cuts his relief lines and takes off for the day. A few hours later I went out and started blowing off the dust from the pad with my leaf blower and had literal chunks of the top layer coming off with the dust. You can imagine my feeling at that moment. There has been a lot of back and forth the last week or so between the contractor and I but no definite decisions made. It is unfortunately starting to eat into other timelines for other aspects of the build. I thought I would turn to you folks for opinions.

 

[mcbane]

You should clear any repair detail with the engineer who designed the structure and with the permitting agency. No idea where you are but particularly in earthquake country you don’t want to make ad hoc changes to a design.

The rebar might have been run from footings to slab out of convenience or just on general principles to tie everything together… But if it was intended to carry any specific loads it must be verified that any drilled in and epoxied “fix” is capable of carrying those design loads.

 

[Flatblackratrod]

You should clear any repair detail with the engineer who designed the structure and with the permitting agency. No idea where you are but particularly in earthquake country you don’t want to make ad hoc changes to a design.

The rebar might have been run from footings to slab out of convenience or just on general principles to tie everything together… But if it was intended to carry any specific loads it must be verified that any drilled in and epoxied “fix” is capable of carrying those design loads.

Thanks for for quick reply. I am in Iowa Engineered drawings are not required, the county has specific guidelines for foundations based on the sq footage and type of building (stick built vs pole). As far as loads go I assume the rebar was tied into the footings as general principles or a "that's how we do it every time on our garage slabs" rather than any specific loads. The building itself is a basic rectangle nothing too crazy. We have to deal with tornadoes and derechos here in Iowa but not so much with quakes. Freeze thaw is usually the most the ground moves around here.

 

[egdede]

I'd be more thinking it was the finishers than the mix.

 

[The Cobbler]

I'd be more thinking it was the finishers than the mix.

I agree

if it is the mix, I think you'd have to remove it all and start over

 

[ConCretin]

Delamination occurs when rising bleed water and air are trapped under the surface when it is sealed too quickly during finishing. It usually occurs in hot windy conditions especially if air entrained concrete is used.

The only situation I can think of where the ready mix company would be liable is if they mistakenly added air entraining admixture to the concrete. Other than that the fault lies with the decision to place in adverse conditions without mitigating the risk and/or improper finishing.

Unless there are other factors involved, the underlying concrete is likely to be structurally fine. The extent of the delamination can be determined by dragging a chain across the surface and listening for changes in tone.

You could overlay the slab using a number of methods and materials -or- the top 1/8-1/4" could be ground off and polished. Unfortunately neither method is cheap but a serviceable result could be achieved.

The best method might just be removal and replacement. If he has acknowledged responsibility, your finisher should go good for the whole job including the concrete. Just bust up the slab, dowel back into the footings and place a new slab. Honestly, that's what I'd probably do. It ***** for him but it comes with the territory. Ask me how I know.

 

[Flatblackratrod]

Well here is where we sit as of last night I'm going to guess you can tell what the decision was!! I have had several mixed opinions on whether or not I should pin the new slab back to the footings. Most of the suggestions since we have freeze thaw cycles have been to let it float.

Interesting for some reason my picture isn't uploading but we cut away from the footings and started the tear out yesterday

 

[benwah]

Ugh, I am dealing with this same issue all over Colorado the last couple years.

Basically what I have been doing is grinding the failing cream layer off, applying a self-leveling cementitious mortar, grind that, then a Double Broadcast Quartz flooring system using Polyaspartic. It's a PITA but seems to be holding up well so far