huangyhg

nde for reinforced concrete
i am working on a project where we need to rehabilitate an existing arch bridge. we would like to better delineate the extent of poor-condition concrete and resteel within the arch member prior to actually digging into it.
i would appreciate hearing about your experiences in using nde for evaluation/assessment of existing rc structures. leads to specific consultants that you would recommend would be appreciated as well.
jeff
there is something called a windsor probe test that can check the hardness of the concrete which can be used to estimate the compressive strength.
there are also methods that can be used to map out the rebar and i believe estimate the corrosion. i'm not real familar with them, but i think they use an electric current.
there's a book called concrete repair and maintenance illustrated by ph emmons (rsmeans cmd group) that discusses some of these techniques.
python is one company that specializes in concrete repair. there was also a company around here called structural preservations systems, but i don't know if they are still in business.
few months back, we had a similar discussion. check the link below-
i would stay away from windsor probe...hit a piece of aggregate and the number jacks way up. use on on a finished slab and the numbers jack way up. in my opinion, it's only good for get additional data since it primarily evaluates the surface conditions of the concrete.
i suggest looking in to ultrasonic methods. you can find a good explanation of it on the link by me at the link provided by shin25. i'm not sure you'll ever be able to tell if laps are okay without seeing it for yourself. there are systems out there that can help identify the location (and maybe size) of rebar.

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