Maybe an engineer can tell me…I have been noticing these circular holes in random spots on the roads I ride. They are about 4" in diameter and usually of a depth of about 2-4". Sometimes they have grass growing in them. It looks like someone came along with a hole cutter and drilled a perfect core sample of the pavement. Just wondering if anyone else has any idea of what I am talking about and what they are for.
Signpost holes or they will put GPS markers in.
No, no these are scattered all over the road, almost always in the travel lanes. You got to watch for them and avoid them while riding. I have hit quite a few, no flats yet though.
They have grass growing in them? Sounds like some hippies don’t really understand what a pothole is.
Maybe a picture is in order…
we have water access holes in alot of our roads, but they all have little metal covers that used to be level with the street before they repaved and didn’t move the access. I hate hitting those things.
Could be a roadbed core sample that they didn’t bother to fill in or maybe something to allow for expansion w/0 cracking in the summer?
Test samples for road surfaces. We have them all over the place. Usually there will be a sign on the side of the road with a “Test Pavement” this or that statement on it.
R10C is right. Core samples of the roadway. They take these to check that the contractor is putting down the right thickness of asphalt. By coring the road the owner (local/state/feds) can be sure that the right amount of material is being applied to the roadway. Looking at a fresh cut sample it is fairly clear how thick the new material was placed. I forgot if the other lab tests were done with that sample or with a sample taken from the trucks.
Concrete is tested when it comes off of the truck. Those are the 6" x 12" gray plastic cylinders that you see sometimes. These are taken back to a lab and tested for strength after a specified number of days. Other tests are performed on site when the concrete truck arrives prior to the concrete being poured. There are more tests performed on concrete than asphalt if my memory is still good (I worked in a testing facility a few years back - 19 years ago).
Thanks! I figured there was a reason. It would have been nice for the crews to fill in the holes afterwards. Now I can say I have learned something new today.
Yea, but the crew that drills the holes is from the testing company and not the paving company. Also all they could do is pour a mix into the hole, and they wouldn’t be able to compact it vary well. So shortly, we would end up with a little hole anyway.
The holes are a bother to bikes, but not so much for cars.
Good point…I knew I would get answers on ST 
.
I actually made those little holes in the road one summer. However, we (I worked for the paving company by the way) then had to fill the holes. It was pretty funny, we’d basically take a bucket of pavement off the back of the truck, shovel it in and hit it a specified number of times with a weight that had to be lifted a specific distance (same as the testing done on the pavement…long story there).
You could always see where the cores were cut, and they always settled…or chipped…or something. Even by following the book 100% (which I can admit, summer students hardly ever do) the core zones always morphed into little holes by the end of the year.
I used to do that kind of work as well. The concrete samples were fun. We had to pressure test them by putting them in a hydraulic press and watch the needle until it gave way. Sometimes the concrete wouldn’t give but the press would keep going. We’d run like hell out of the trailer because when it finally did go, it was like a bomb going off. The concrete cylinder would actually explode into chunks.
Sounds like those sections of road are due for an overlay.
I am guessing that working for the paving company…none of your samples failed the thickness requirement. Seems like a conflict of interest to me…but I guess that is no worse than when they tell you exactly where they will be taking the samples, before you lay the asphalt down.
I remembered the first time we messed with those fiberglass strengthened mixes. The testing machine would bounce when it finally broke. Of course back then we capped our cylinders with a very pleasant moltent sulphur mix.
I am guessing that working for the paving company…none of your samples failed the thickness requirement. Seems like a conflict of interest to me…but I guess that is no worse than when they tell you exactly where they will be taking the samples, before you lay the asphalt down.
Core samples are often taken by the contractor to monitor the job or to estimate a resurface job. Most asphalt roads are recycled and the contractor needs to know what is there to take up before the resurfacing. An independent engineer does the testing for the “owner”.