Severely Deteriorated Concrete Wall

[SteelPE]

I visited a potential project with a contractor client today. This existing wall (age unknown, but it's not new) has begun to severely deteriorate.

Now, the client isn't really interested in why the wall is in bad shape but I am.

It almost appears as if the mix was too large (as I would have guessed the aggregated to be 3"). It also looks like over 50% of the mix was aggregate. The fine aggregate and cement mixture just seems to be falling apart. You can pick it apart with your fingers. This project is located in the Northeast US so it is routinely exposed to freezing and thawing cycles.

Does anyone have any idea as to what might be the cause of the deterioration we are seeing?

 

[phamENG]

I find the shape of the deterioration to be especially interesting. I'd be interested to see how water flows over the site (and the wall) in a heavy rain.

Is it just me, or is there no rebar in that upper section? I see a couple things that could be corroded steel, but it's mostly loose aggregate. Maybe some of the aggregate has sulfides in it?

It also looks like there are some vertical cracks that align with the fence posts. Maybe water working in there combined with some oxide jacking by the steel posts?

 

[GC_Hopi]

I will hazard a guess on the horizontal crack... cold joint which saw freeze thaw and has deteriorated.

 

[SteelPE]

In the first picture, you can see that the lower section of wall is a bit beat up, but is in good shape. I don't think these two sections were constructed at the same time.

In regards to rebar, I don' think there is any rebar in the upper section of the wall. I think there is some rebar in the lower section.

I have the worst eyes to spot grade differences, so I don't know exactly what is happening with regards to the grade on the upper section of the wall. This wall is 700' +/- long. There is impervious bituminous asphalt on the upper section of the wall for parking over 1/2 of the length of the wall. Over the remaining length of wall, the bituminous turns to a gravel/dirt area that really isn't maintained that much (maybe they knock down the weeds once or twice a year).

Sulfides is a possibility (this area of the northeast is beginning to have issues with sulfides). I asked the client if he was interested in getting a test and he had no idea what I was talking about and didn't seem interested in getting a test done at all.

 

[bridgebuster]

I agree it's not a well-graded mix. There appears to be a combination of broken stone and smooth gravel. Could one of the factors be ASR? If there's a lot of quartz in the mix, it could be ASR.

 

[emmgjld]

By the whitish coloring, my first question would be;
Could this be sulfates, possibly migrating through the wall from the soil side?
2nd question would be;
What is the real soil moisture/free ground water (possibly perched) conditions?
I would have no other questions until these 2 are answered.

 

[dik]

It doesn't look like ASR (unless massive aggregate problem) or sulphate (again, unless massive, I've seen concrete turn to aggregate, and basically disappear). Do you have any tests on the soil type or constituents? From the colour, it appears to be a very low strength concrete; do you have an idea of the strength? Could be massive sulphate attack on very weak concrete. Is there a possibility for water saturation and frost damage (not likely possible in Florida or other places). Any information about the construction and/or mix design (half a bag of cement to a yard of aggregate)? My initial reaction is to replace it with something that works... or leave it and let nature take its course.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Do you feel any better?

-Dik

 

[SteelPE]

I have no idea how old the wall is. We proposed a full remove and replace of the entire wall. This proposal has since been rejected by the bean counters. I suggested the owner send his chief bean counter out here so see for him/herself how bad the concrete is. When you can pull aggregate our of the wall with no tools you know you have an issue. I'm sure the bean counter will not care as they like to keep all the beans for themselves.

Personally I am not being asked to repair the wall. I am being asked to design the replacement wall where the owner deems wall needs to be removed and replaced. I am just interested in why the wall looks like it does to further my education.

I have asked to get the wall cored and analyzed, but haven't heard back yet from the client on this proposal.

 

[epoxybot]

Judging by the tweak in the fence it looks like this section of concrete has shifted. How thick is the wall and is there any chance the ground behind the fence is backed by rising ground?