FAA and Nuclear Density Gauges
FAA and Nuclear Density Gauges
(OP)
Does anyone know where I may find information or articles about the use of nuclear gauges for density testing on airports (United States FAA only). It seems there may have been some discussions (debating?) at one point between the FAA and various parties on whether or not the gauges are appropriate for use with *subbase* during airport construction.
Thanks in advance.
Thanks in advance.





RE: FAA and Nuclear Density Gauges
RE: FAA and Nuclear Density Gauges
RE: FAA and Nuclear Density Gauges
Is this a result of 9/11/01 or is there some other reason? I have seen nuclear testing used on many private and state/local government jobs.
RE: FAA and Nuclear Density Gauges
Many states and other federal agencies allow their use.
As for control of these devices as a result of increased threats of "dirty bombs", I have not seen memos or other correspondence from the regulatory agencies. The controls on the devices are already reasonably stringent, though there have been lost ones and thefts over the years. Fortunately, their radioisotope sources are rather weak and probably wouldn't be much good for anything other than their present use!
RE: FAA and Nuclear Density Gauges
I was talking about crushed stone subbase, ITEM P-154: SUBBASE COURSE. The FAA does, as far as I know, allow the gauges to be used within the airport. I didn't know that the gauges would pose that much threat or inconvienence as you make them out to be. I'm sure the FAA is in its own world though.
Ron:
I may be missing something, but I think you are wrong in saying that the gauges have never been allowed on FAA projects. You did say that they have never been allowed under the "general specifications" (versus special provisions), which may be true--in that case you would be correct.
If you were saying that the gauges are NEVER allowed (only the ballon or sand cone), then I think you are mistaken. I'm not totally familar with the FAA specifications, so it got confusing for me really fast while reading through your referenced article. I couldn't find the original specifications that these modifications are supposed to be applied to. I also couldn't find any where they state that only the ballon/sand cone are acceptable methods. In fact, I found the opposite after reading some "notes to the engineer" which give additional stipulations if the guages are used. If you follow the link below, you will see some modifications regarding crushed subbase (P154). Scroll down to 3.8 in this link.
http://www.faa.gov/arp/ace/aipguide/ce1370_p154.htm
I may have misunderstood you, but it sounded like you were claiming the guages are not allowed, period. Correct me if I'm wrong.
Thanks.
RE: FAA and Nuclear Density Gauges
I have run into similar issues with US Army Corps of Engineers projects. When correlation studies are presented, sometimes you can get other methods approved for use.
In the most current version of P-154, only the rubber balloon and sand cone are specified.
RE: FAA and Nuclear Density Gauges
RE: FAA and Nuclear Density Gauges
You say it took over a week of compaction. What was the contractors method? It sounds like they continously rolled the material for a week? I would think that the subase would dry out (and drain) much of the moisture after a week, thus adding to their difficulty. Did they continue to apply water. Was the subase brought to the site at the correct moisture content, or was water only blended upon spreading and the start of the compaction?
Excessive rolling/vibrating can cause water to migrate upwards within subgrade. Was their any subgrade problems? *I would think* that excessive rolling/vibrating of dry material would also cause the material to start breaking up on the surface. Did this happen at all?