x-raying to detect necked down rebar due to corrosion
x-raying to detect necked down rebar due to corrosion
(OP)
Can x-raying be used to detect corrosion severed #6 rebar that has necked down to threadlike proportions and severed (as found in sme locations in chipped out inspection pits?
Has anyone done that successfully?
GPR has been tried and does not work because of the separation planes.
It is 2" mastic asphalt, then 1" concrete topping (mostly debonded), 1/8 asphaltic membrane, 7½" thick 2-way reinforced slab, then 2½" thick drop panel. Total thickness = 13.125" approx. 2-way slab. Top bars specified cover ¾".
Has anyone done that successfully?
GPR has been tried and does not work because of the separation planes.
It is 2" mastic asphalt, then 1" concrete topping (mostly debonded), 1/8 asphaltic membrane, 7½" thick 2-way reinforced slab, then 2½" thick drop panel. Total thickness = 13.125" approx. 2-way slab. Top bars specified cover ¾".






RE: x-raying to detect necked down rebar due to corrosion
If you are looking at the bottom bars in the slab you have a much better chance of a good image as the object to film distance is lower, resulting in a more distinct image. For top bars, they will look "fuzzier" as an image.
A few difficulties.....
First, the thickness of the slab will dictate a very long time shot (upwards of 60 minutes or more) using Iridium 192. If you can find a lab that has a Cobalt 60 radioisotope, the shooting time would be less, but there's probably only a handful of labs that have Cobalt 60 in North America.
Secondly, because of the long shot time, there will have to be a large safe perimeter established in every direction as these are live radioactive isotopes (an x-ray machine is not powerful enough to shoot through concrete, effectively) using gamma rays and they are dangerous and highly regulated.
Third, the image size is going to be limited to what you can get onto a 4"x17" film or multiples of the 4" width, keeping in mind that the wider the film shot, there is a higher likelihood that the source to film distance will need to be increased, thus increasing the shot time even more.
......and, it's expensive!!
But to go back to your original question, yes....you can show what you described.
RE: x-raying to detect necked down rebar due to corrosion
RE: x-raying to detect necked down rebar due to corrosion
RE: x-raying to detect necked down rebar due to corrosion
RE: x-raying to detect necked down rebar due to corrosion
As Ron mentions, Iridium is easier to deal with but may not have the pop you need, and I second the cost comment.
IC
RE: x-raying to detect necked down rebar due to corrosion
RE: x-raying to detect necked down rebar due to corrosion
RE: x-raying to detect necked down rebar due to corrosion