Observed, and homeowner commented on, this pockmarked concrete present on the sidewalk and driveway.
The voids shown in the picture were numerous over the surface of the concrete. If you look at the pictures you can see the progression of the problem. They start as the crack, then progress into a hole. (progression pictures are from right to left) The sizes varied.
Apparently the homeowner’s neighbor has already had an inspection and the builder has agreed to replace the driveway and sidewalk ( a rarity around here in my experience.)
My question is, What is the problem called? What causes it? How would you write it up?
These look more like what masons call popouts. generally a cone-like fragment that breaks out of the concrete surface. Usually the result of porous aggregate or a chemical reaction between the cement and certain aggregates. Repairable but will probably be very noticeable.
There are many variable and answers to this potential problem and causes.
This is concrete and has not been fully Master as to it’s affects and related problems in 2000 years.
Patching the problem as one said in the above post will show, but there are products out there that could be brushed on, such as Ardex CD that would and can bring the surface to an almost identical finish that would be acceptable to the surrounding area of concrete color.
Its called too much water in the mix. The super was probably gone when they poured the driveway and sidewalk, and the grunts didnt want to labor to spread the concrete. So they went and turned on the garden hose and watered down the mix so it was easy to spread. They were able to finish quickly and finish off the day with a couple of beers.
This seems to be a good explaination. These were very specific spots. They were well defined and relatively deep. The dark material in the hole was what I would identify as the bad aggreigate in question, no asphault was present.
Depending on the “age” and progression of different “holes” this dark aggregate was in various stages of deterioration. In some it was pretty solid and flakey, others (presumably older ones) it was more powdery.
This was something I haven’t seen to this extent before. I doubt patching is going to be acceptable to the homeowner. I dont blame them, most patch jobs I see look worse than the origianal problem. Besides, the problem seems to exist throughout the pour. So patching what shows now would only be a stopgap measure.
What super? Around here the “supers” have 30 houses a piece and make no effort to actually visit them on a regular basis. The crews are always on their own, and know it. Hence the level of quality shown…
Me too. The homeowner as well. It is a new house, the problem will just get worse with patching and time. They should not have to put up with it. It is actually one of the better CS builders, so I think they will get a new pour.
I was interested in specifics for my own education and to try and find the best way to write it up in my report, without trying to act like a concrete expert - which I am not.
If that dark stuff is the sub-grade, then the concrete was poured to thin in a few spots and that’s part of it. The rest has something to do with expansion of the aggragate for some reason. I think Shawn’s on the right track.
Out here the Supers visit Torrey Pines Golf Course and the Zoo during the day, and visit the titty bars at night. Being so tired from their work day, it is possible that they will miss a few things. :margarit: