Comments From Past Concrete Scanning Posts

Comments From Past

Concrete Scanning Posts

30 Comments and Responses Retained from the site Concrete Scanner NDT Services with Ground Penetrating Radar.

Since these comments are chosen from the archives, images were added to assist with illustrating the question being addressed. The archives did not have any images. The topics include concrete scanning large sites with 100’s of locations, the availability of a GPR concrete scanner that cost less than $2000, can a HILTI PS1000 detect diameter, separation, thickness and depth for steel in reinforced concrete structures, I am curious to find out if there is a stash of goods under my basement floor, I need concrete scanning equipment in Saudi Arabia, searching for gold in a filled gully, I need to locate rebar in 27″ thick slab of concrete, I am looking for a way to locate post tension cables in a garage concrete slab, and looking to confirm the thickness of newly poured concrete.

  1. Comments about Concrete Scan 200 Locations August 9, 2013 at 6:39 am #

    Dear sir, we need to scan the MS conduit pipes already laid in the slab , the scaning is required becauce we need to do core cutting for plumbing works , the no of holes is around 200, and this may increase please give your location to find.
    • Concrete Scanner August 9, 2013 at 9:16 am #
      Would all of the concrete scanning be done all at one time? Or, would a few GPR surveys be done, wait a period of time, and then do some more? Where do you need a concrete scanner?
      • Comments about Manage concrete scanning 200 locations.

        Manage concrete scanning 200 locations.

        Concrete Scan 200 Locations August 9, 2013 at 10:48 am #
        we can do all at a time ,after confirming the conduit abscene area Trivandrum , india
      • Concrete Scanner August 9, 2013 at 11:51 am #
        Thank you for your inquiry. It sounds like a great concrete scanning project. However, I do not have a GPR system or a concrete scanner in the Trivandrum area at this time.
  2. Comments about Low Cost GPR July 15, 2013 at 5:26 pm #

    I need an inexpensive way to scan 8 floors in the same area for rebar or pipes before we drill. Need lowest cost possible and work asap. Job is in Hialeah.
    • Concrete Scanner July 16, 2013 at 2:38 pm #
      What do you mean by low cost?
      • Low Cost GPR July 16, 2013 at 2:52 pm #
        Couple of $1000
        • Concrete Scanner July 16, 2013 at 3:35 pm #
          Unless you need a concrete scanner to survey one or two locations per floor I think you need to rethink costs. If you find a concrete scanner to do that volume of concrete scanning for a “couple of $1000,” I suspect you may want to budget for repairs. You often get what you pay for.
  3. Comments about Buy A Concrete Scanner June 24, 2013 at 1:10 pm #

    I’ve just found your website coincidentially, looking for refferences to buy online a Concrete Scanner for my father. We just know about this HILTI PS 1000 (He’s actually looking for PS2000 which was not on the internet). It was really usefull to have found your web page but the thing is, we don`t know much about companies that produce this kind of device. We live in Colombia, south America. My father just finished a master’s degree in Material’s Pathology Analysis and it`ll be really helpfull for him and his team to include this in their work equipment. Basically what would be important to get for them it’ll be a scanner that can detect diameter, separation, thickness and depth for steel in reinforced concrete structures. Can you reccommend or suggest anything or maybe, tell us about a price range or something? Thank you and again very interesting website, Have a very nice day.
    • Concrete Scanner June 25, 2013 at 7:23 am #
      There are a couple of different concrete scanners manufactured. While the physics behind the technology is basically the same, the packaging and ability to create long term documentation of the GPR results is important to me. I used Sensors & Software Ground Penetrating Radar systems for a couple of decades. I am comfortable with their Conquest, Noggin, and pulseEKKO systems. I find that the Conquest works well for small areas, while the Noggin or pulseEKKO systems have few limitations and are able to image any size area. I often create plan view plots of entire rooms 10’s of feet in size. I also find that a concrete scanner needs to be able post process the results to get the greatest sensitivity.
  4. Comments about Beneath Basement Floor June 1, 2013 at 4:46 pm #

    How much would it cost to find out what (if anything) is beneath 3 basement rooms in a house in Minneapolis?
    • Concrete Scanner June 2, 2013 at 7:50 am #
      To use a GPR concrete scanner, I need to know a little more about the site. I am assuming the floor is concrete. Do you know what type of reinforcing material is has? What are the dimensions of the three rooms? How are they shaped? Are the rooms open and clear of any features that can obstruct the concrete scanner survey? Also, what do you mean by “anything?” I need to know the size and what you are looking for? Metal, voids, plastic, and other all respond differently to GPR. Also, how deep are you interested in investigating? Is the basement large enough to stand up in? What is the application (e.g., business, personal, or government)?
      • Beneath Basement Floor June 2, 2013 at 10:34 am #
        The ceilings are about 7′-6″ high in two of the rooms, and about 9′ high in the other room. (guestimates) The floors are made of concrete, and I have no idea what the reinforcing material is, although the original blue prints indicate that a 3/8″ diameter reinforcing rod was used in the concrete floors, as it was built in 1921. The rooms are approximately 14′ X 10′, 14′ X 10′, 10′ X 23′. The rooms are clear and open.
        By “anything”, I am just curious as to if there is anything under the floors for 2 reasons:
        1.) The floors in 2 of these rooms sound hollow when one jumps on them. Which is odd to me.
        2.) We already know that there was some bootlegging activity done on the premises back in the day (not too surprising, as it was built during prohibition),so I was curious if there was a connection there. It might just be nothing….possibly just a void under the floor. It is just my curiosity about the house that makes me want to find out everything I can about it. The application is personal and am an architect. I am super excited to just find out everything I can about it. I was asking an archaeologist friend of mine about ground penetrating radar and your site is one of the two she recommended I contact.
        • Comments about Concrete Scanning a Basement Floor

          Concrete Scanning a Basement Floor

          Concrete Scanner June 2, 2013 at 11:59 am #
          Depending on the level of confidence you are looking to achieve, it would take a concrete scanner one or two days to geophysically characterize the subsurface using GPR. If you want great detail, the concrete scanning would need to be done on a grid with perpendicular lines spaced about 3 inches apart. Based on your response (not looking for utilities in the concrete, interested in large voids imediately below the slab, you expect rebar so wire mesh does not seem to be an issue, and this is a personal application), the three rooms could be concrete scanned with a 1000 MHz GPR system in one day, assuming lines are spaced fairly far apart in two perpendicular directions. However, if this was a commercial application that involved penetrations, I would expect you would want a higher level of confidence. A higher level of confidence is associated with more closely spaced lines and would take a second day on site.
          • Beneath Basement Floor June 2, 2013 at 2:21 pm #
            Would I see what is in the voids?
          • Concrete Scanner June 2, 2013 at 6:14 pm #
            The high frequency GPR will likely respond well to the top of a void but after that it is difficult to know what the signal will do. To determine the thickness of a void is often difficult unless it is fairly deep or large. The signal has a tendency of bouncing around inside the void.
  5. Comments about Re-bar Scanner Saudi Arabia May 9, 2013 at 9:39 am #

    We have concrete members. We want to check the reinforcement by Rebar Scanner. Is your Rebar scanning service available in dammam (Saudi Arabia).
    • Concrete Scanner May 9, 2013 at 10:42 am #
      I do not have a GPR concrete scanner in Dammam at this time. I am forwarding your request to Sensors & Software, the manufacture of the equipment I use most of the time. They may be able to provide you with a contact that is near you.
  6. Comments about Gold In A Gully April 19, 2013 at 3:37 pm #

    search for gold in a filled gully
    • Concrete Scanner April 20, 2013 at 9:42 am #
      Unless you are looking for a vein in a rock formation or buckets of gold, it is very difficult to locate gold using any type of GPR. I am not going to say it has not been done but it almost takes a crystal ball. However, if you have specific geologic conditions (e.g. a bedrock depression or a type of overburden you are looking to locate), more general geophysical methods may assist you. A 1000 MHz concrete scanner would likely penetrate less than a foot or two, if solid rock or dry sand.
      • Gold In A Gully April 20, 2013 at 1:48 pm #
        There’s a gully maybe 40 yards wide that has been filled in over time. The center of the gully under all that fill is roughly 20-30 ft deep. There is gold there (drilled and confirmed). My thought was to walk the gully with a GPR and seek out drops (like baby waterfalls) in the gully floor (under all that sand) where gold concentrations would be at their maximum. I’m sure the unit can provide this 3d image of the floor and any drops (can it?). I am hoping it may also be able to discern any metallic items (alluvial gold concentrations) in those drops to confirm the presence so digging is not in vain. We don’t want to excavate the entire gully running through a wash plant of we can cherry pick the deposits.
        • Concrete Scanner April 20, 2013 at 2:11 pm #
          Unlike many people who ask for assistance, you are trying to better define the geology. The big question is what type of access do you have. Is it very brushy or a lot of boulders or other obstacles. The best results are obtained from areas with sand and gravel and little water at depth. A lower frequency ground penetrating radar unit could possibly reach these depths of interest. The best results are obtained by constructing a grid and collecting data in two perpendicular directions. As for detecting gold, the deposits are typically too sparse. It isn’t so much the thickness but the lateral extent. You would likely need a nearly continuous layer of gold that is a couple of meters in diameter. I am sure you would be happy to find such a deposit but how often does that occur.
  7. Comments about Thick Concrete March 21, 2013 at 12:33 pm #

    I am in the Jackson Ms area, and I work for Storm Ready Shelters. We have sold an above ground shelter to a home owner in the area that has post tension cables. I am trying to determine how to drill without damage.
    Thanks,
    • Concrete Scanner March 22, 2013 at 3:04 pm #
      How thick is the concrete?
      • Thick Concrete March 26, 2013 at 11:32 am #
        Need to locate rebar in 27″ thick mat
        • Concrete Scanner March 29, 2013 at 1:07 pm #
          Submitted on 2013/03/30 at 1:07 pm | In reply to Thick Concrete.
          Often a Sensors & Software 1000 MHz GPR unit is used to scan concrete for rebar, cables, pipe, and post tension cables. The higher frequency antenna provides greater detail. However, you indicated that you want to reach depths of penetration up to 27 inches. If there are not many shallow targets in the 27 inch slab you may get better penetration with a lower frequency 500 MHz antenna. However, you will loose resolution with the 500 MHz antenna, which can effect the ability to delineate smaller diameter targets at depth. In either case, this may be a difficult task.
  8. Comments about Garage Slab March 2, 2013 at 10:41 am #

    I am looking for a way to locate post tension cables in a garage conccrete slab.
    • Concrete Scanner March 2, 2013 at 11:22 am #
      High frequency ground penetrating radar is often used to locate post tension cables. Often a 1000 MHz antenna is used; however, if you require greater depths of penetration you may want to consider a 500 MHz GPR antenna. Please realize there are other factors that may contribute to desirable results.
  9. Comments about New Green Concrete February 13, 2013 at 9:59 am #

    Have newly poured concrete slab 22′ x 36′. Location Northeastern MI. Need to determine thickness, between 3″ to 6″.
    • Concrete Scanning Newly Poured Concrete

      Concrete scanning newly poured concrete

      Concrete Scanner February 13, 2013 at 11:05 am #
      Ground penetrating radar does not perform well over newly poured concrete. While the concrete may be hard enough to walk on there remains, for some time, electrically conductive moisture within the pores. I also believe there is a significant amount of chlorides in the concrete that can increase the conductivity of the concrete. How old is the slab? How soon do you need to determine the concrete thickness?

 

The contents of this post has various merits. As one can see, the comments are from 2013, when the format of ConcreteScanner.com offered this open forum. Shortly after this format was implemented, it was decided to go strictly to an email based system for responding to people questions. At times it was impractical to assist people in the open form. In addition to spam, there were issues of confidentiality and quality of content. As any web site owner knows, a large volume of comments are submitted by spammers looking for free advertising or a way to insert links to there sites. The spam content is often overwhelming because it is easily generated by other computers. For these reasons and others, we decided try to provide content throughout the website that would answer a majority of the peoples questions. As always, feel free to contact either through the contact page or through one of the pages that offer comments.

 

 

 

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