Slab thickness testing

[CFNick]

Does anyone know of a way to have slab thickness verified without coring through the slab? If so, are there any companies in particular who might specialize in this operation?

Thanks,
Nick

 

[Bagman2524]

I've seen a ultrasonic testing called "pulse echo technique" used to determine crack depths in a deep slab. A place called Design House in North Carolina performed the test. I'm not sure if they are still in business.

 

[Lutfi]

Try Ground penetrating Radar (GPR). It may be of help as well. You may call one for the GPR service providers and check with them.



Regards,
Lutfi

 

[CFNick]

Thanks for the info. I have contacted a company about the GPR, but it is not precise enough for the exact dimensions I need. They use the GPR more for soil densities than concrete thickness. I'll have to see if there are any ultrasonic testing companies here in Florida.

 

[pba]

If you find what you are looking for please update this post with the information.

Many years ago a company I worked for tried to establish floor thickness using both GPR and ultrasonic tests with no particular success. I would expect that the technique has advanced since then.

Even if you do get a good result it may be necessary to drill the slab to calibrate the results.

Out of interest why can't you core the floor?

 

[PEinc]

Rather than coring holes, can't you just drill several small diameter drill holes through the slab? These small holes would not be very noticeable and could be easily patched.

 

[LittleWheels]

Impact Echo sounds like it might do the job.

How accurate do you need to be? The more accurate your requirement, the more likely you are to result to coring or drilling.

http://www.iti.northwestern.edu/pubs/landis.html

is one website explaining some possible techniques

 

[Ron]

Contact Olsen Engineering in Colorado. The sell this type of equipment and their latest versions are reported to be pretty good. Pulse echo and GPR won't do it accurately. Impact echo has a chance.

 

[Lutfi]

It has been my experience that the core thickens only represents that particular zone it is taken from unless several random cores are taken and an average is computed.

Thickness will depend on how level was the slab base was prepared. It is my opinion that variations in slab thickness that range from 1/4 to 1/2 inch are normal for slabs on grade.


Regards,
Lutfi