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4247 views
06:03 Mar-11-2008
Anand
Concrete -Radiography


Hi All
Please let me know if there is any possiblity of taking a radiograph on a concrete. If so please let me know about the techniques and the principle involved


 
09:03 Mar-11-2008
Simon Amallraja
Re: Concrete -Radiography ----------- Start Original Message -----------
:
: Hi All
: Please let me know if there is any possiblity of taking a radiograph on a concrete. If so please let me know about the techniques and the principle involved
------------ End Original Message ------------

You can try Digital Flat Panel System from Vidisco Ltd, Israel. Check the details @ www.vidisco.com

Simon


 
09:30 Mar-11-2008

Michel

NDT Inspector,
consultant,
Canada,
Joined Sep 2006
818
Re: Concrete -Radiography ----------- Start Original Message -----------
: :
: : Hi All
: : Please let me know if there is any possiblity of taking a radiograph on a concrete. If so please let me know about the techniques and the principle involved
: You can try Digital Flat Panel System from Vidisco Ltd, Israel. Check the details @ www.vidisco.com
: Simon
------------ End Original Message ------------


The approximate Radiographic Equivalence Fator for concrete to steel is 10: 1. Use Agfa D7 or D8 with 0.010" Pb screen and Co-60 for source.



 
03:29 Mar-12-2008
JF
Re: Concrete -Radiography ----------- Start Original Message -----------
:
: Hi All
: Please let me know if there is any possiblity of taking a radiograph on a concrete. If so please let me know about the techniques and the principle involved
------------ End Original Message ------------

IR-192 good for up to ~8-in. CO-60 good for up to ~12-in. Geometric factors must be considered & source-side markers essential. ASNT used to have a paper posted (~2002 Back-to-basics) titled "Radiography for Building Renovation", a concrete radiography treatise. Find that one and your questions are answered. Good hunting!



 
06:59 Mar-12-2008

bob sudharmin

Engineering, Reliability and Integrity Eng
Shell Malaysia Trading,
Malaysia,
Joined Jan 2008
54
Re: Concrete -Radiography Concrete is one of the materials used as a shield for radiation apart from lead. What would be expected of radiography on concrete, then?

----------- Start Original Message -----------
:
: Hi All
: Please let me know if there is any possiblity of taking a radiograph on a concrete. If so please let me know about the techniques and the principle involved
------------ End Original Message ------------




 
08:17 Mar-12-2008

Patrick Garland

Consultant,
P J Garland & Associates,
South Africa,
Joined Jun 2000
5
Re: Concrete -Radiography Hi,
I have radiographed 450mm thick concrete beams to determine the presence, location, size and quantity of steel reinforcing for the confirmation of the design strength of a bridge.
Please let me know what your application is and what you are hoping to find.
Regards,
Pat Garland

----------- Start Original Message -----------
: Concrete is one of the materials used as a shield for radiation apart from lead. What would be expected of radiography on concrete, then?
: :
: : Hi All
: : Please let me know if there is any possiblity of taking a radiograph on a concrete. If so please let me know about the techniques and the principle involved
------------ End Original Message ------------




 
00:14 Mar-12-2008
Anand
Re: Concrete -Radiography ----------- Start Original Message -----------
: Hi,
: I have radiographed 450mm thick concrete beams to determine the presence, location, size and quantity of steel reinforcing for the confirmation of the design strength of a bridge.
: Please let me know what your application is and what you are hoping to find.
: Regards,
: Pat Garland
: : Concrete is one of the materials used as a shield for radiation apart from lead. What would be expected of radiography on concrete, then?
: : :
: : : Hi All
: : : Please let me know if there is any possiblity of taking a radiograph on a concrete. If so please let me know about the techniques and the principle involved
------------ End Original Message ------------

hi
it is the same application . buit i want to kow the techniques involved and also it is like the normal radiography.
Anand


 
08:43 Mar-13-2008
Nazir Shaikh
Re: Concrete -Radiography recently I have seen a digital radiograph which clearly showed location of conduits and reba. i am also interested to know up to what depth can a radiograph detect the location of rebar and conduits.

------ Start Original Message -----------
: : Hi,
: : I have radiographed 450mm thick concrete beams to determine the presence, location, size and quantity of steel reinforcing for the confirmation of the design strength of a bridge.
: : Please let me know what your application is and what you are hoping to find.
: : Regards,
: : Pat Garland
: : : Concrete is one of the materials used as a shield for radiation apart from lead. What would be expected of radiography on concrete, then?
: : : :
: : : : Hi All
: : : : Please let me know if there is any possiblity of taking a radiograph on a concrete. If so please let me know about the techniques and the principle involved
: hi
: it is the same application . buit i want to kow the techniques involved and also it is like the normal radiography.
: Anand
------------ End Original Message ------------




 
09:41 Mar-15-2008

Michel

NDT Inspector,
consultant,
Canada,
Joined Sep 2006
818
Re: Concrete -Radiography ----------- Start Original Message -----------
: recently I have seen a digital radiograph which clearly showed location of conduits and reba. i am also interested to know up to what depth can a radiograph detect the location of rebar and conduits.
: ------ Start Original Message -----------
: : : Hi,
: : : I have radiographed 450mm thick concrete beams to determine the presence, location, size and quantity of steel reinforcing for the confirmation of the design strength of a bridge.
: : : Please let me know what your application is and what you are hoping to find.
: : : Regards,
: : : Pat Garland
: : : : Concrete is one of the materials used as a shield for radiation apart from lead. What would be expected of radiography on concrete, then?
: : : : :
: : : : : Hi All
: : : : : Please let me know if there is any possiblity of taking a radiograph on a concrete. If so please let me know about the techniques and the principle involved
: : hi
: : it is the same application . buit i want to kow the techniques involved and also it is like the normal radiography.
: : Anand
------------ End Original Message ------------

Nazir,

In reference to your question of how deep can a radiograph see? Well it's not the radiograph, but rather the source of radiation and its strength that will allow you to do the job. From what I know of digital radiography, you are able to cut down your exposure time or by keeping the same exposure in theory you could go much deeper. As I have stated before, you are looking at a radiographic equivalent of 10:1 (ciment-steel).


 
06:17 Mar-20-2008

Adam Stasuk

NDT Inspector, - -
Stasuk Testing & Inspection Ltd.,
Canada,
Joined Mar 2008
29
Re: Concrete -Radiography ----------- Start Original Message -----------
: : recently I have seen a digital radiograph which clearly showed location of conduits and reba. i am also interested to know up to what depth can a radiograph detect the location of rebar and conduits.
: : ------ Start Original Message -----------
: : : : Hi,
: : : : I have radiographed 450mm thick concrete beams to determine the presence, location, size and quantity of steel reinforcing for the confirmation of the design strength of a bridge.
: : : : Please let me know what your application is and what you are hoping to find.
: : : : Regards,
: : : : Pat Garland
: : : : : Concrete is one of the materials used as a shield for radiation apart from lead. What would be expected of radiography on concrete, then?
: : : : : :
: : : : : : Hi All
: : : : : : Please let me know if there is any possiblity of taking a radiograph on a concrete. If so please let me know about the techniques and the principle involved
: : : hi
: : : it is the same application . buit i want to kow the techniques involved and also it is like the normal radiography.
: : : Anand
: Nazir,
: In reference to your question of how deep can a radiograph see? Well it's not the radiograph, but rather the source of radiation and its strength that will allow you to do the job. From what I know of digital radiography, you are able to cut down your exposure time or by keeping the same exposure in theory you could go much deeper. As I have stated before, you are looking at a radiographic equivalent of 10:1 (ciment-steel).
------------ End Original Message ------------

There is actually a non-linear ratio when attempting to radiograph concrete. We have found that it is approximately 4:1 steel for the lower thickness capabilities of Ir192 or Co60 and increases to 3:1 or greater as you reach the limits of the penetration of Ir192 or Co60.

The capability of any x-ray or gamma source of penetrating concrete and producing images with sufficient quality is more dependent on the energy level used for the given thickness.

We have found that Co60 becomes useless over approximately 800mm of standard structural concrete. Where as a 4-6 MeV Accelerator will penetrate up to 1100mm effectively. I have also heard of more powerful accelerators penetrating as high as 1600mm.

Above these maximum thickness factors the primary beam exposure to the film becomes unresponsive to using longer exposures and you only typically get film darkening due to secondary scatter.

Once a radiation source use is decided on then sensitivity and ability to differentiate internal objects becomes a factor. You must consider geometry when deciding your source to film distance and your object to film distance. Obviously the contact to the film and the maximum feasible SFD is the most desirable but may be time prohibitive. Simple trigonometry and a drawing layout of the source cross section and the source to film distance will show how much coverage you get and will also show the amount of effective "blowout" you can expect from a rebar/conduit/PT cable found closest to the source by the time it is imaged on the film.

One note of caution when trying to radiograph thick sections: Although rebar/conduit/PT cable that may appear to be near the outside of edge your shot it can actually be located near the center of your shot but due to it's proximity to the source is projected to the outer edge of the film. A rule of thumb is the sharper the image of the object the closer it likely is to the film side. You can typically differentiate between all metal based materials but our technicians have found that plastic conduits often appear as slightly darker voids and are usually defined when a linear darker pattern can be observed on the film.


 
06:42 Mar-20-2008
chris s
Re: Concrete -Radiography ----------- Start Original Message -----------
: : : recently I have seen a digital radiograph which clearly showed location of conduits and reba. i am also interested to know up to what depth can a radiograph detect the location of rebar and conduits.
: : : ------ Start Original Message -----------
: : : : : Hi,
: : : : : I have radiographed 450mm thick concrete beams to determine the presence, location, size and quantity of steel reinforcing for the confirmation of the design strength of a bridge.
: : : : : Please let me know what your application is and what you are hoping to find.
: : : : : Regards,
: : : : : Pat Garland
: : : : : : Concrete is one of the materials used as a shield for radiation apart from lead. What would be expected of radiography on concrete, then?
: : : : : : :
: : : : : : : Hi All
: : : : : : : Please let me know if there is any possiblity of taking a radiograph on a concrete. If so please let me know about the techniques and the principle involved
: : : : hi
: : : : it is the same application . buit i want to kow the techniques involved and also it is like the normal radiography.
: : : : Anand
: : Nazir,
: : In reference to your question of how deep can a radiograph see? Well it's not the radiograph, but rather the source of radiation and its strength that will allow you to do the job. From what I know of digital radiography, you are able to cut down your exposure time or by keeping the same exposure in theory you could go much deeper. As I have stated before, you are looking at a radiographic equivalent of 10:1 (ciment-steel).
: There is actually a non-linear ratio when attempting to radiograph concrete. We have found that it is approximately 4:1 steel for the lower thickness capabilities of Ir192 or Co60 and increases to 3:1 or greater as you reach the limits of the penetration of Ir192 or Co60.
: The capability of any x-ray or gamma source of penetrating concrete and producing images with sufficient quality is more dependent on the energy level used for the given thickness.
: We have found that Co60 becomes useless over approximately 800mm of standard structural concrete. Where as a 4-6 MeV Accelerator will penetrate up to 1100mm effectively. I have also heard of more powerful accelerators penetrating as high as 1600mm.
: Above these maximum thickness factors the primary beam exposure to the film becomes unresponsive to using longer exposures and you only typically get film darkening due to secondary scatter.
: Once a radiation source use is decided on then sensitivity and ability to differentiate internal objects becomes a factor. You must consider geometry when deciding your source to film distance and your object to film distance. Obviously the contact to the film and the maximum feasible SFD is the most desirable but may be time prohibitive. Simple trigonometry and a drawing layout of the source cross section and the source to film distance will show how much coverage you get and will also show the amount of effective "blowout" you can expect from a rebar/conduit/PT cable found closest to the source by the time it is imaged on the film.
: One note of caution when trying to radiograph thick sections: Although rebar/conduit/PT cable that may appear to be near the outside of edge your shot it can actually be located near the center of your shot but due to it's proximity to the source is projected to the outer edge of the film. A rule of thumb is the sharper the image of the object the closer it likely is to the film side. You can typically differentiate between all metal based materials but our technicians have found that plastic conduits often appear as slightly darker voids and are usually defined when a linear darker pattern can be observed on the film.
------------ End Original Message ------------

On a side note, set up of these shots can be difficult. the two best methods that I've found are 1) drill a small dia. pilot hole. 2) use a small high powered magnet on one side and agauss meter on the other.


 
07:08 Mar-20-2008
Keith Moxey
Re: Concrete -Radiography Hi
J M E sell and hire portable Betatrons with energy outputs of 6MeV and 7.5MeV which are regularly used for inspecting concrete. Penetration depths vary due to density variations of the concrete, but a rough guide is 1 metre thickness for film and up to 1.5 metres for flat panel detectors. the small focal spot size and broad energy spectrum of the Betatron compared with Gamma sources results in higher quality radiographs.
Regards
Keith Moxey
---------- Start Original Message -----------
: : : : recently I have seen a digital radiograph which clearly showed location of conduits and reba. i am also interested to know up to what depth can a radiograph detect the location of rebar and conduits.
: : : : ------ Start Original Message -----------
: : : : : : Hi,
: : : : : : I have radiographed 450mm thick concrete beams to determine the presence, location, size and quantity of steel reinforcing for the confirmation of the design strength of a bridge.
: : : : : : Please let me know what your application is and what you are hoping to find.
: : : : : : Regards,
: : : : : : Pat Garland
: : : : : : : Concrete is one of the materials used as a shield for radiation apart from lead. What would be expected of radiography on concrete, then?
: : : : : : : :
: : : : : : : : Hi All
: : : : : : : : Please let me know if there is any possiblity of taking a radiograph on a concrete. If so please let me know about the techniques and the principle involved
: : : : : hi
: : : : : it is the same application . buit i want to kow the techniques involved and also it is like the normal radiography.
: : : : : Anand
: : : Nazir,
: : : In reference to your question of how deep can a radiograph see? Well it's not the radiograph, but rather the source of radiation and its strength that will allow you to do the job. From what I know of digital radiography, you are able to cut down your exposure time or by keeping the same exposure in theory you could go much deeper. As I have stated before, you are looking at a radiographic equivalent of 10:1 (ciment-steel).
: : There is actually a non-linear ratio when attempting to radiograph concrete. We have found that it is approximately 4:1 steel for the lower thickness capabilities of Ir192 or Co60 and increases to 3:1 or greater as you reach the limits of the penetration of Ir192 or Co60.
: : The capability of any x-ray or gamma source of penetrating concrete and producing images with sufficient quality is more dependent on the energy level used for the given thickness.
: : We have found that Co60 becomes useless over approximately 800mm of standard structural concrete. Where as a 4-6 MeV Accelerator will penetrate up to 1100mm effectively. I have also heard of more powerful accelerators penetrating as high as 1600mm.
: : Above these maximum thickness factors the primary beam exposure to the film becomes unresponsive to using longer exposures and you only typically get film darkening due to secondary scatter.
: : Once a radiation source use is decided on then sensitivity and ability to differentiate internal objects becomes a factor. You must consider geometry when deciding your source to film distance and your object to film distance. Obviously the contact to the film and the maximum feasible SFD is the most desirable but may be time prohibitive. Simple trigonometry and a drawing layout of the source cross section and the source to film distance will show how much coverage you get and will also show the amount of effective "blowout" you can expect from a rebar/conduit/PT cable found closest to the source by the time it is imaged on the film.
: : One note of caution when trying to radiograph thick sections: Although rebar/conduit/PT cable that may appear to be near the outside of edge your shot it can actually be located near the center of your shot but due to it's proximity to the source is projected to the outer edge of the film. A rule of thumb is the sharper the image of the object the closer it likely is to the film side. You can typically differentiate between all metal based materials but our technicians have found that plastic conduits often appear as slightly darker voids and are usually defined when a linear darker pattern can be observed on the film.
: On a side note, set up of these shots can be difficult. the two best methods that I've found are 1) drill a small dia. pilot hole. 2) use a small high powered magnet on one side and a gauss meter on the other.
------------ End Original Message ------------




 
00:26 Mar-21-2008

Michel

NDT Inspector,
consultant,
Canada,
Joined Sep 2006
818
Re: Concrete -Radiography ----------- Start Original Message -----------
: : : : recently I have seen a digital radiograph which clearly showed location of conduits and reba. i am also interested to know up to what depth can a radiograph detect the location of rebar and conduits.
: : : : ------ Start Original Message -----------
: : : : : : Hi,
: : : : : : I have radiographed 450mm thick concrete beams to determine the presence, location, size and quantity of steel reinforcing for the confirmation of the design strength of a bridge.
: : : : : : Please let me know what your application is and what you are hoping to find.
: : : : : : Regards,
: : : : : : Pat Garland
: : : : : : : Concrete is one of the materials used as a shield for radiation apart from lead. What would be expected of radiography on concrete, then?
: : : : : : : :
: : : : : : : : Hi All
: : : : : : : : Please let me know if there is any possiblity of taking a radiograph on a concrete. If so please let me know about the techniques and the principle involved
: : : : : hi
: : : : : it is the same application . buit i want to kow the techniques involved and also it is like the normal radiography.
: : : : : Anand
: : : Nazir,
: : : In reference to your question of how deep can a radiograph see? Well it's not the radiograph, but rather the source of radiation and its strength that will allow you to do the job. From what I know of digital radiography, you are able to cut down your exposure time or by keeping the same exposure in theory you could go much deeper. As I have stated before, you are looking at a radiographic equivalent of 10:1 (ciment-steel).
: : There is actually a non-linear ratio when attempting to radiograph concrete. We have found that it is approximately 4:1 steel for the lower thickness capabilities of Ir192 or Co60 and increases to 3:1 or greater as you reach the limits of the penetration of Ir192 or Co60.
: : The capability of any x-ray or gamma source of penetrating concrete and producing images with sufficient quality is more dependent on the energy level used for the given thickness.
: : We have found that Co60 becomes useless over approximately 800mm of standard structural concrete. Where as a 4-6 MeV Accelerator will penetrate up to 1100mm effectively. I have also heard of more powerful accelerators penetrating as high as 1600mm.
: : Above these maximum thickness factors the primary beam exposure to the film becomes unresponsive to using longer exposures and you only typically get film darkening due to secondary scatter.
: : Once a radiation source use is decided on then sensitivity and ability to differentiate internal objects becomes a factor. You must consider geometry when deciding your source to film distance and your object to film distance. Obviously the contact to the film and the maximum feasible SFD is the most desirable but may be time prohibitive. Simple trigonometry and a drawing layout of the source cross section and the source to film distance will show how much coverage you get and will also show the amount of effective "blowout" you can expect from a rebar/conduit/PT cable found closest to the source by the time it is imaged on the film.
: : One note of caution when trying to radiograph thick sections: Although rebar/conduit/PT cable that may appear to be near the outside of edge your shot it can actually be located near the center of your shot but due to it's proximity to the source is projected to the outer edge of the film. A rule of thumb is the sharper the image of the object the closer it likely is to the film side. You can typically differentiate between all metal based materials but our technicians have found that plastic conduits often appear as slightly darker voids and are usually defined when a linear darker pattern can be observed on the film.
: On a side note, set up of these shots can be difficult. the two best methods that I've found are 1) drill a small dia. pilot hole. 2) use a small high powered magnet on one side and a gauss meter on the other.
------------ End Original Message ------------

Hi Chris,

I believe you wrote a note on this topic. Quote:"On a side note, set up of these shots can be difficult. the two best methods that I've found are 1) drill a small dia. pilot hole. 2) use a small high powered magnet on one side and a gauss meter on the other." Unquote.

Can you please tell me what you are refering to, because I can figure out why you would do this. Thanks in advance for your enlightening.

Cheerios,

Michel




 
02:05 Mar-21-2008
chris s
Re: Concrete -Radiography ----------- Start Original Message -----------
: : : : : recently I have seen a digital radiograph which clearly showed location of conduits and reba. i am also interested to know up to what depth can a radiograph detect the location of rebar and conduits.
: : : : : ------ Start Original Message -----------
: : : : : : : Hi,
: : : : : : : I have radiographed 450mm thick concrete beams to determine the presence, location, size and quantity of steel reinforcing for the confirmation of the design strength of a bridge.
: : : : : : : Please let me know what your application is and what you are hoping to find.
: : : : : : : Regards,
: : : : : : : Pat Garland
: : : : : : : : Concrete is one of the materials used as a shield for radiation apart from lead. What would be expected of radiography on concrete, then?
: : : : : : : : :
: : : : : : : : : Hi All
: : : : : : : : : Please let me know if there is any possiblity of taking a radiograph on a concrete. If so please let me know about the techniques and the principle involved
: : : : : : hi
: : : : : : it is the same application . buit i want to kow the techniques involved and also it is like the normal radiography.
: : : : : : Anand
: : : : Nazir,
: : : : In reference to your question of how deep can a radiograph see? Well it's not the radiograph, but rather the source of radiation and its strength that will allow you to do the job. From what I know of digital radiography, you are able to cut down your exposure time or by keeping the same exposure in theory you could go much deeper. As I have stated before, you are looking at a radiographic equivalent of 10:1 (ciment-steel).
: : : There is actually a non-linear ratio when attempting to radiograph concrete. We have found that it is approximately 4:1 steel for the lower thickness capabilities of Ir192 or Co60 and increases to 3:1 or greater as you reach the limits of the penetration of Ir192 or Co60.
: : : The capability of any x-ray or gamma source of penetrating concrete and producing images with sufficient quality is more dependent on the energy level used for the given thickness.
: : : We have found that Co60 becomes useless over approximately 800mm of standard structural concrete. Where as a 4-6 MeV Accelerator will penetrate up to 1100mm effectively. I have also heard of more powerful accelerators penetrating as high as 1600mm.
: : : Above these maximum thickness factors the primary beam exposure to the film becomes unresponsive to using longer exposures and you only typically get film darkening due to secondary scatter.
: : : Once a radiation source use is decided on then sensitivity and ability to differentiate internal objects becomes a factor. You must consider geometry when deciding your source to film distance and your object to film distance. Obviously the contact to the film and the maximum feasible SFD is the most desirable but may be time prohibitive. Simple trigonometry and a drawing layout of the source cross section and the source to film distance will show how much coverage you get and will also show the amount of effective "blowout" you can expect from a rebar/conduit/PT cable found closest to the source by the time it is imaged on the film.
: : : One note of caution when trying to radiograph thick sections: Although rebar/conduit/PT cable that may appear to be near the outside of edge your shot it can actually be located near the center of your shot but due to it's proximity to the source is projected to the outer edge of the film. A rule of thumb is the sharper the image of the object the closer it likely is to the film side. You can typically differentiate between all metal based materials but our technicians have found that plastic conduits often appear as slightly darker voids and are usually defined when a linear darker pattern can be observed on the film.
: : On a side note, set up of these shots can be difficult. the two best methods that I've found are 1) drill a small dia. pilot hole. 2) use a small high powered magnet on one side and a gauss meter on the other.
: Hi Chris,
: I believe you wrote a note on this topic. Quote:"On a side note, set up of these shots can be difficult. the two best methods that I've found are 1) drill a small dia. pilot hole. 2) use a small high powered magnet on one side and a gauss meter on the other." Unquote.
: Can you please tell me what you are refering to, because I can figure out why you would do this. Thanks in advance for your enlightening.
: Cheerios,
: Michel
------------ End Original Message ------------

Michel, what i was trying to convey was that it can be difficult to set up the shot. The film and source have to be lined up on opposite sides of the concrete. This can be difficult without something to reference your location.


 
05:01 Mar-22-2008

Michel

NDT Inspector,
consultant,
Canada,
Joined Sep 2006
818
Re: Concrete -Radiography ----------- Start Original Message -----------
: : : : : : recently I have seen a digital radiograph which clearly showed location of conduits and reba. i am also interested to know up to what depth can a radiograph detect the location of rebar and conduits.
: : : : : : ------ Start Original Message -----------
: : : : : : : : Hi,
: : : : : : : : I have radiographed 450mm thick concrete beams to determine the presence, location, size and quantity of steel reinforcing for the confirmation of the design strength of a bridge.
: : : : : : : : Please let me know what your application is and what you are hoping to find.
: : : : : : : : Regards,
: : : : : : : : Pat Garland
: : : : : : : : : Concrete is one of the materials used as a shield for radiation apart from lead. What would be expected of radiography on concrete, then?
: : : : : : : : : :
: : : : : : : : : : Hi All
: : : : : : : : : : Please let me know if there is any possiblity of taking a radiograph on a concrete. If so please let me know about the techniques and the principle involved
: : : : : : : hi
: : : : : : : it is the same application . buit i want to kow the techniques involved and also it is like the normal radiography.
: : : : : : : Anand
: : : : : Nazir,
: : : : : In reference to your question of how deep can a radiograph see? Well it's not the radiograph, but rather the source of radiation and its strength that will allow you to do the job. From what I know of digital radiography, you are able to cut down your exposure time or by keeping the same exposure in theory you could go much deeper. As I have stated before, you are looking at a radiographic equivalent of 10:1 (ciment-steel).
: : : : There is actually a non-linear ratio when attempting to radiograph concrete. We have found that it is approximately 4:1 steel for the lower thickness capabilities of Ir192 or Co60 and increases to 3:1 or greater as you reach the limits of the penetration of Ir192 or Co60.
: : : : The capability of any x-ray or gamma source of penetrating concrete and producing images with sufficient quality is more dependent on the energy level used for the given thickness.
: : : : We have found that Co60 becomes useless over approximately 800mm of standard structural concrete. Where as a 4-6 MeV Accelerator will penetrate up to 1100mm effectively. I have also heard of more powerful accelerators penetrating as high as 1600mm.
: : : : Above these maximum thickness factors the primary beam exposure to the film becomes unresponsive to using longer exposures and you only typically get film darkening due to secondary scatter.
: : : : Once a radiation source use is decided on then sensitivity and ability to differentiate internal objects becomes a factor. You must consider geometry when deciding your source to film distance and your object to film distance. Obviously the contact to the film and the maximum feasible SFD is the most desirable but may be time prohibitive. Simple trigonometry anda drawing layout of the source cross section and the source to film distance will show how much coverage you get and will also show the amount of effective "blowout" you can expect from a rebar/conduit/PT cable found closest to the source by the time it is imaged on the film.
: : : : One note of caution when trying to radiograph thick sections: Although rebar/conduit/PT cable that may appear to be near the outside of edge your shot it can actually be located near the center of your shot but due to it's proximity to the source is projected to the outer edge of the film. A rule of thumb is the sharper the image of the object the closer it likely is to the film side. You can typically differentiate between all metal based materials but our technicians have found that plastic conduits often appear as slightly darker voids and are usually defined when a linear darker pattern can be observed on the film.
: : : On a side note, set up of these shots can be difficult. the two best methods that I've found are 1) drill a small dia. pilot hole. 2) use a small high powered magnet on one side and a gauss meter on the other.
: : Hi Chris,
: : I believe you wrote a note on this topic. Quote:"On a side note, set up of these shots can be difficult. the two best methods that I've found are 1) drill a small dia. pilot hole. 2) use a small high powered magnet on one side and a gauss meter on the other." Unquote.
: : Can you please tell me what you are refering to, because I can figure out why you would do this. Thanks in advance for your enlightening.
: : Cheerios,
: : Michel
: Michel, what i was trying to convey was that it can be difficult to set up the shot. The film and source have to be lined up on opposite sides of the concrete. This can be difficult without something to reference your location.
------------ End Original Message ------------

Now I understand! Thanks for clearing that up.

Cheerios,

Michel




 
02:30 Mar-26-2008

Floyd Atkinson

NDT Inspector
American Inspection Society, Inc.,
USA,
Joined Jun 2004
10
Re: Concrete -Radiography vs. James R meter
I know this is off the wall. Has anyone examined concrete for metallic rebar size and location? It could be done with metallic conduit also. I have done this type of inspection on post tensioned house / buildings slabs, walls and bridge pylons supports. I then laid out the grids of the reinforcements locations with large sized chalk. I took digital camera photos for back up documentation. I washed down my artwork after the projects task was over.

It is done with the magnetism principle. and to have a known standard for calibration.

See the enclosed Website URL address for more details.

Have a great day!

Floyd, The "can do" QC Guy


----------- Start Original Message -----------
: : : : : : : recently I have seen a digital radiograph which clearly showed location of conduits and reba. i am also interested to know up to what depth can a radiograph detect the location of rebar and conduits.
: : : : : : : ------ Start Original Message -----------
: : : : : : : : : Hi,
: : :: : : : : : I have radiographed 450mm thick concrete beams to determine the presence, location, size and quantity of steel reinforcing for the confirmation of the design strength of a bridge.
: : : : : : : : : Please let me know what your application is and what you are hoping to find.
: : : : : : : : : Regards,
: : : : : : : : : Pat Garland
: : : : : : : : : : Concrete is one of the materials used as a shield for radiation apart from lead. What would be expected of radiography on concrete, then?
: : : : : : : : : : :
: : : : : : : : : : : Hi All
: : : : : : : : : : : Please let me know if there is any possiblity of taking a radiograph on a concrete. If so please let me know about the techniques and the principle involved
: : : : : : : : hi
: : : : : : : : it is the same application . buit i want to kow the techniques involved and also it is like the normal radiography.
: : : : : : : : Anand
: : : : : : Nazir,
: : : : : : In reference to your question of howdeep can a radiograph see? Well it's not the radiograph, but rather the source of radiation and its strength that will allow you to do the job. From what I know of digital radiography, you are able to cut down your exposure time or by keeping the same exposure in theory you could go much deeper. As I have stated before, you are looking at a radiographic equivalent of 10:1 (ciment-steel).
: : : : : There is actually a non-linear ratio when attempting to radiograph concrete. We have found that it is approximately 4:1 steel for the lower thickness capabilities of Ir192 or Co60 and increases to 3:1 or greater as you reach the limits of the penetration of Ir192 or Co60.
: : : : : The capability of any x-ray or gamma source of penetrating concrete and producing images with sufficient quality is more dependent on the energy level used for the given thickness.
: : : : : We have found that Co60 becomes useless over approximately 800mm of standard structural concrete. Where as a 4-6 MeV Accelerator will penetrate up to 1100mm effectively. I have also heard of more powerful accelerators penetrating as high as 1600mm.
: : : : : Above these maximum thickness factors the primary beam exposure to the film becomes unresponsive to using longer exposures and you only typically get film darkening due to secondary scatter.
: : : : : Once a radiation source use is decided on then sensitivity and ability to differentiate internal objects becomes a factor. You must consider geometry when deciding your source to film distance and your object to film distance. Obviously the contact to the film and the maximum feasible SFD is the most desirable but may be time prohibitive. Simple trigonometry and a drawing layout of the source cross section and the source to film distance will show how much coverage you get and will also show the amount of effective "blowout" you can expect from a rebar/conduit/PT cable found closest to the source by the time it is imaged on the film.
: : : : : One note of caution when trying to radiograph thick sections: Although rebar/conduit/PT cable that may appear to be near the outside of edge your shot it can actually be located near the center of your shot but due to it's proximity to the source is projected to the outer edge of the film. A rule of thumb is the sharper the image of the object the closer it likely is to the film side. You can typically differentiate between all metal based materials but our technicians have found that plastic conduits often appear as slightly darker voids and are usually defined when a linear darker pattern can be observed on the film.
: : : : On a side note, set up of these shots can be difficult. the two best methods that I've found are 1) drill a small dia. pilot hole. 2) use a small high powered magnet on one side and a gauss meter on the other.
: : : Hi Chris,
: : : I believe you wrote a note on this topic. Quote:"On a side note, set up of these shots can be difficult. the two best methods that I've found are 1) drill a small dia.pilot hole. 2) use a small high powered magnet on one side and a gauss meter on the other." Unquote.
: : : Can you please tell me what you are refering to, because I can figure out why you would do this. Thanks in advance for your enlightening.
: : : Cheerios,
: : : Michel
: : Michel, what i was trying to convey was that it can be difficult to set up the shot. The film and source have to be lined up on opposite sides of the concrete. This can be difficult without something to reference your location.
: Now I understand! Thanks for clearing that up.
: Cheerios,
: Michel
------------ End Original Message ------------




 
12:00 Jan-26-2016
Ali Adam
Re: Concrete -Radiography In Reply to Anand at 06:03 Mar-11-2008 (Opening).

Dear Sir,
Happy new year
Many thanks for your response and support, i want to collect information to radiography concrete to locate reinforcement bars by gamma ray (Ir 192) so i need concrete factor.
Best Regards
ALI ADAM
26/01/2016

 


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