Cold Weather Concrete 1

[jlholt911969]

I'm in Minnesota and I engineered a custom home with a three story below grade foundation system on a lake. The owner owns a construction company and I had them install a permanent sheet pile retaining wall to lower the lateral soil load on the basement walls around the house. The foundation wall height is roughly 28' at the tallest part of the house. Although this is a residence it is more like some of the commercial jobs that I have done since it incorporates very tall concrete walls, precast panel floors, and a very large steel moment frame along the lakeside wall. The concrete contractor poured the foundation walls when the temperatures were below 40 degrees F and some of them at below -1 F. I have looked online to find out what the effects of temperature on the placement would be but can only find references to flatwork. The concrete walls were cored in various locations and tested and met the required strengths, but I have concerns about bonding between steel and concrete. According to the owner’s representative’s limited observations, the contractor did not follow any kind of cold weather protocols as my general notes require. The walls texture is very rough just about everywhere, which indicates to me that the surface water in the concrete was flash frozen by the forms, and when the forms were removed the face of the walls were left pitted and terrible looking on the surface. If that happened to the surface, what happened at the surfaces of the two layers of rebar that were just as cold. Where can I find information on the effects of cold weather placement of concrete in walls?

This is just one of many issues that I have been made aware of by the Homeowner, and the owner has asked me to decide as to the integrity of the whole foundation. I figured I would start on this part of it, but here are a few other items that I will be tackling very soon. No special inspections were done as I required on the plans schedule, consolidation issues have been seen in some areas, the owner had GPR testing done and they found missing steel at the tops of the walls, and there are diagonal cold joints throughout the project. Taken individually I would be concerned, but these issues are all on the same foundation. Any advice on how to proceed with the forensic analysis? Should I tackle each issue one at a time or would it be better to view the issues as a whole from a wider perspective?

 

[dik]

Freezing concrete can be unpredictable. It depends on the state of hydration of the mix when the freezing occurs. I understand you can use petrographic study to determine if this has occurred; I've not used it, so I'm not sure. The effects can also be long term durability...
Taking it down to -1F is quite cool... we often experience -30C here.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Canuck65]

If you are in Minnesota and want a concrete question such as yours expertly answered, contact Beton Consulting Engineers. They will deal with whatever needs to be tested with respect to the concrete material (petrography, etc....).

Situation seems not good. Gather the facts, express concern, present the facts to the owner/contractor, and have the contractor retain their own expert to review and respond. It's the contractor's mistake, make them do the work, then you review and respond diligently to the contractors responses. At the same time, get testing done by Beton. In my opinion, all issues should be gathered and dealt with together.

Normally if the concrete can gain strength adequately within the first 24 hours, subsequent freezing will usually not damage the concrete, but will delay the strength gain. If the concrete freezes in the first 24 hours ... not good.