Poured Concrete Wall Problem

[Munster1]

We just poured a concrete basement (new construction).
10' walls, 10" wide, on a 24" footer (@8" deep).

During pouring a form collapsed, concrete was knocked out and the form was reset. Pour was continued.

Unfortunately the concrete sat in the pump during this reform time and began to seperate giving some severe honeycombing all the way through both sides on top of what is now a cold joint. It's a wavy line about 25 feet long. We discovered this when we pulled the forms. Yes, he should have dumped it out and used fresh mix but he didn't. Trying to minimize $$.

Of course the contractor said "it'll be fine" but it looks like heck and I'm worried about both structural and water intrusion. He offered to cut it out and repour.

Would I be better with a planned vertical cold joint from the cut and repour (will it settle?, will it leak?) or should I try to have them repair the honeycomb along the joint?

I'm also concerned about breaking the footer if we try to remove it and just making my problem worse. Can you piece the footer without problems? It's a big project, and bulldozing and starting over would be very expensive.

What's the best way to fill the honeycomb if it's structurally okay?

This will be a finished basement with a 2 story on top or it. I don't want problems down the line.

Any help?
Hermon

 

[SacreBleu]

There are plenty of high-tech grout products made by Sika that would do the trick. Your contractor should foot the bill. By the way, "footer" is contractor lingo - we call them footings. :_)

 

[SlideRuleEra]

Concur with SacreBleu that there are products and techniques to make the repair.

However when forms fail there is often other damage, such as rebar cage shifting, or bulges in the forms at other locations. Suggest that you give serious consideration to having the Contractor replace the wall - at this time, I assume this is his problem, not yours. It will become yours if the repairs are unsuccessful.

http://www.SlideRuleEra.net

 

[Munster1]

Thanks for the info.
The wall does in fact have a bulge (bow), but it's outside the house on the retaining wall, I wasn't too worried.

I believe there are standards for rebar sizes, placements and grouting on joining these walls (if we cut it out and repour), where would I find them? It seems I have inherited the responsibility for the fix, since they have minimal experience with repairs, only pouring new walls as a business, and don't want to employ an engineer.

I am hiring an engineer to do structural checks. What other concerns should I have? Is is okay to have a cold joint in the footing? Does it need a pier?

Thanks again,
Hermon

 

[jike]

Munster1:

I don't believe you indicated in your original post whether this is an unreinforced or reinforced concrete wall, so I will ask the obvious question.....is it reinforced with vertical and horizontal bars?

 

[Munster1]

Good question, and I don't know to what extent it's reinforced, but will find out. Some vertical bars are visible in the honeycomb, I assume it's only vertical. I know it was tied to the footing this way.

Thanks

 

[Barbicane]

There is usually enough safety factor to take care of some contractor related problems. It would bother me if the contractor, fearing that the concrete was about to take an initial set, added water to the mix to make the last of the pour go better. It might have been that adding water before the first of the pour contributed to the original problem. Usually, basements are waterproofed with an external coating of bitumenous material or highly dense cements with high fractions of iron powder. A perfectly poured wall can still conduct water from outside to inside, usually at the cold joint with the footing. Delays in pours are not usually disasterous if temperatures are mild or even cool.

 

[jike]

If this is an unreinforced wall, supported top and bottom, and there is a horizontal cold joint, I would be very concerned about the integrity of the wall to transfer lateral forces to the supports. I would have much less concern if the wall has continuous vertical reinforcement.

It is common knowledge that when a concrete pump initially is started up, there is an initial slug of concrete that comes out that usually is very runny and not of the proper consistency. This should be dumped, before beginning the work.