Crack Repair in Thin Concrete Wall

[8thStreet]

I designed a concrete wall system that is similar in shape and size to CMU wall. It has an outer and inner face shell of 2" of grout and a 6" void in the middle, so the total wall thickness is 10". The walls are connected with small perpendicular walls about ever 12" or so. Think of a CMU block, but made out of grout /shot crete.

The contractor filled the void with too much spray foam and the face of one walls bulged out and cracked. There are two 1/2" wide cracks running vertical all the way up the wall about 12" apart (between the perpendicular walls). Imagine the face shell of CMU core breaking out.

Do you have any suggestions for crack repair? I am leaning towards removing the section of broken "face shell" and rebuilding the face shell with a Sika Rapair Grout over the hardened spray form to bond it back together.

If this was cmu wall with vertical cracks, what would be the preferred method of repair?

 

[Ron]

This is not a masonry wall so the repair is different.

Remove the are and repair with new repair mortar. Sika is good. Make sure you have continuity of reinforcing.

Seems like a stretched design.

 

[MIStructE_IRE]

From your description it sounds like you’ve done a shotcrete version of a diaphragm brick wall something like the attached?

2” face sounds thin. Is it mesh reinforced? How do the internal ribs connect to the faces? If they were adequately tied its unlikely that foam would cause it to bulge over a 12” span?

 

[8thStreet]

Yes. It is very similar to diaphragm brick construction, but on a much smaller scale. This is a single story home and the walls are made out of shotcrete like product. The novel approach is that the walls are placed by a 3D printer.

The walls are placed in 2" lifts and we place wire ladder reinforcing at every foot. The front and back walls are tied together with grout at 12" o.c. and with the ladder reinforcing. After visiting the site and inspecting the crack - it appears that this area lacked ladder reinforcing installation, so the concrete only wasn't able to resist the tension force of the spray foam.

I think we are going to remove the damaged portion, form it up, and pour a new concrete wall at this location.