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- since 1996 -
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Technical Discussions
David Hirsch
David Hirsch
00:06 Oct-29-2000
Concrete thickness testing, needs solution

The requirement is to measure the thickness of precast reinforced
concrete products, particularly concrete pipes and culverts before they
are installed i.e. in the factory yard or on the delivery site.

The product thickness can range from around 50 mm to 120 mm with easy
access to the external product surfaces but limited and difficult access to
the internal surface - as for example, in the case of a small diameter
pipe 2.5 m long.

Steel reinforcement content and pattern will vary with each product

Measurement accuracy desirably should be of the order of 2% but if
necessary up to 5% would be considered.

Portable battery operated equipment would be preferred, but is not
essential.

Products may have a thin plastic sheet lining over part of the internal
surface

Ideally the instrument should enable a thickness profile to be obtained
by traversing along the length of the product. If some form of
calibration is needed it would be possible to physically measure the
thickness at the beginning and end of such a traverse

Moisture content, cement content and degree of compaction of the concrete
may vary between products but should be consistent in each individual
product.

Obviously the radius of curvature of the external surface of a pipe is
dependent on the pipe diameter - a minimum external diameter of 750 mm is
envisaged.

If the above information is insufficient please advise what other information
is required.



    
 
 Reply 
 
Joseph Pascente
Engineering
Lixi, Inc., USA, Joined Nov 1998, 39

Joseph Pascente

Engineering
Lixi, Inc.,
USA,
Joined Nov 1998
39
05:46 Oct-29-2000
Re: Concrete thickness testing, needs solution
Dear David,

The Lixi Profiler will measure both walls at the
same time with 2% repeatable accuracy. Your Email
address David Hirsch
came back as non deliverable.


    
 
 Reply 
 
William Friedman
R & D,
Lockheed Martin, USA, Joined Nov 1998, 6

William Friedman

R & D,
Lockheed Martin,
USA,
Joined Nov 1998
6
05:20 Nov-13-2000
Re: Concrete thickness testing, needs solution
: The requirement is to measure the thickness of precast reinforced
: concrete products, particularly concrete pipes and culverts before they
: are installed i.e. in the factory yard or on the delivery site.

I suggest you look at the Impact Echo technique which has been shown to
be effective at measuring the thickness of reinforced
concrete. Check the response in this forum by William
Streett on 12 May 1999 for more information and references.


    
 
 Reply 
 
Giuseppe Nardoni
Director
I&T Nardoni Institute, Italy, Joined Dec 1999, 4

Giuseppe Nardoni

Director
I&T Nardoni Institute,
Italy,
Joined Dec 1999
4
05:38 Nov-13-2000
Re: Concrete thickness testing, needs solution
In Roma in the exhibition of the 15 World Conference on NDT I have measured
with a potrable instrument from one side the thickness of a 450 mm wall of
the congress hall . The equpmenr works on radar waves principle .The
transducer is a box of 70 x 150 mm with 16 transducers .
For any othe information call me at 0039-348- 2280470 .

best regards
G:.NARDONI
Company : I&T Nardoni Institute

: The requirement is to measure the thickness of precast reinforced
: concrete products, particularly concrete pipes and culverts before they
: are installed i.e. in the factory yard or on the delivery site.

: The product thickness can range from around 50 mm to 120 mm with easy
: access to the external product surfaces but limited and difficult access to
: the internal surface - as for example, in the case of a small diameter
: pipe 2.5 m long.

: Steel reinforcement content and pattern will vary with each product

: Measurement accuracy desirably should be of the order of 2% but if
: necessary up to 5% would be considered.

: Portable battery operated equipment would be preferred, but is not
: essential.

: Products may have a thin plastic sheet lining over part of the internal
: surface

: Ideally the instrument should enable a thickness profile to be obtained
: by traversing along the length of the product. If some form of
: calibration is needed it would be possible to physically measure the
: thickness at the beginning and end of such a traverse

: Moisture content, cement content and degree of compaction of the concrete
: may vary between products but should be consistent in each individual
: product.

: Obviously the radius of curvature of the external surface of a pipe is
: dependent on the pipe diameter - a minimum external diameter of 750 mm is
: envisaged.

: If the above information is insufficient please advise what other information
: is required.




    
 
 Reply 
 
Otto Kroggel
Otto Kroggel
08:45 Dec-01-2000
Re: Concrete thickness testing, needs solution
: The requirement is to measure the thickness of precast reinforced
: concrete products, particularly concrete pipes and culverts before they
: are installed i.e. in the factory yard or on the delivery site.

: The product thickness can range from around 50 mm to 120 mm with easy
: access to the external product surfaces but limited and difficult access to
: the internal surface - as for example, in the case of a small diameter
: pipe 2.5 m long.

: Steel reinforcement content and pattern will vary with each product

: Measurement accuracy desirably should be of the order of 2% but if
: necessary up to 5% would be considered.

: Portable battery operated equipment would be preferred, but is not
: essential.

: Products may have a thin plastic sheet lining over part of the internal
: surface

: Ideally the instrument should enable a thickness profile to be obtained
: by traversing along the length of the product. If some form of
:calibration is needed it would be possible to physically measure the
: thickness at the beginning and end of such a traverse

: Moisture content, cement content and degree of compaction of the concrete
: may vary between products but should be consistent in each individual
: product.

: Obviously the radius of curvature of the external surface of a pipe is
: dependent on the pipe diameter - a minimum external diameter of 750 mm is
: envisaged.

: If the above information is insufficient please advise what other information
: is required.

Dear David,

I can offer an ultrasound equipment, which will solve your problem.
It uses a "dry" coupling and is therefore doesn´t have high requirements with respect to the evenness of the concrete surface.
A little bit of roughness is even better for the coupling
It takes about 1-2 seconds to take a measurement at a single point. the device is battery-operated and stores 960 single measurements in its local memory.
Thedata can easily be transferred from the local memory to a lap-top etc.
The data are represented on a small screen on the device itself in a way making it easy to interpret the results during the measurements and also to judge the concrete with respect to honeycombs etc.

I would not recommend to use Radar techniques, because of the unknown moisture situation in the concrete
Impact -echo application is limited to a certain minimum thickness because of the limitation of the maximum frequency generated by the " hammering mechanism".

Best regards Otto Kroggel


    
 
 Reply 
 
Dan E. Johnson
Dan E. Johnson
01:56 Dec-04-2000
Re: Concrete thickness testing, needs solution
: : The requirement is to measure the thickness of precast reinforced
: : concrete products, particularly concrete pipes and culverts before they
: : are installed i.e. in the factory yard or on the delivery site.
:
: I suggest you look at the Impact Echo technique which has been shown to
: be effective at measuring the thickness of reinforced
: concrete. Check the response in this forum by William
: Streett on 12 May 1999 for more information and references.

David,

I concur with the thoughts presented above regarding Impact Echo testing, as it is an effective measuring tool for reinforced concrete of depths within the thivkness range you require. More information on this technique can be found at www.impactecho.com, including information about the book "Impact Echo - Nondestructive Evaluation of Concrete and Masonry" written by William Streett and Mary Sansalone.


    
 
 Reply 
 
arun sankhat
arun sankhat
05:33 Jul-30-2002
Re: Concrete thickness testing, needs solution
sir,
i would like to know more about the method and how to analyse the stress waves that are reflected back from any discontinuity.
arun

: : : The requirement is to measure the thickness of precast reinforced
: : : concrete products, particularly concrete pipes and culverts before they
: : : are installed i.e. in the factory yard or on the delivery site.
: :
: : I suggest you look at the Impact Echo technique which has been shown to
: : be effective at measuring the thickness of reinforced
: : concrete. Check the response in this forum by William
: : Streett on 12 May 1999 for more information and references.

: David,

: I concur with the thoughts presented above regarding Impact Echo testing, as it is an effective measuring tool for reinforced concrete of depths within the thivkness range you require. More information on this technique can be found at www.impactecho.com, including information about the book "Impact Echo - Nondestructive Evaluation of Concrete and Masonry" written by William Streett and Mary Sansalone.




    
 
 Reply 
 

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