Ground penetrating radar scanning is a technique that helps to locate subsurface (underground, concrete) utilities. The GPR scanning device transmits electromagnetic waves to the concrete slab and receives back the reflected pulses as if facing discontinuities.

Talking about discontinuity, it can be a metal or a plastic object or a debond or delamination. The advantage of using GPR over other devices is its noninvasive way of pinpointing buried or hidden utilities. Isn’t it amazing to spot the wires and pipes buried inside the concrete without disturbing or cutting the concrete? Indeed, it is!

If you are a concrete contractor, builder, or property owner, knowing about GPR services can help you complete your construction project with fewer repairs, onsite safety, and more money savings. But how? Let us keep reading to know the answer.

How does GPR work?

GPR scanning works by sending electromagnetic signals to the slab and measuring the changes in these signals when they reflect back and are received by the antenna. As the pulses enter the concrete or soil, the reflections return based on the buried object's conduction and dielectric properties and surrounding material. Still didn’t get it? Let’s try again:

  • GPR device has two main parts: A transmitter and a receiving antenna. A transmitter sends pulses into the material.
  • The electromagnetic pulse passes through the concrete and reflects back when it hits rebar or plastic.
  • The reflected pulse is received back by the antenna, and the system translator shows the signal distortions on the screen.
  • The time, frequency, and images are all combined and used by the professional to locate the object and its material type.
gpr scanning

Why do we need GPR scanning in Construction?

GPR scanning is used to find objects that are buried inside the concrete and ground. It has a wide range of services in archaeology, investigation, mining, construction, and so on. Here are the reasons why we need GPR in construction:

Ground scanning helps to ensure the safety of a construction spot prior to construction. It helps to locate tunnels, gas pipelines, and hidden abnormalities beneath the surface.

During the construction, scanning helps to mark the right coring spots for electrical and plumbing work. Detecting the location of rebar and post-tension cables helps in safe coring.

In the case of renovating an older building, GPR scanning helps locate buried rebar, pipes, and electric wires. This helps with slab extension and reduction and also prevents coring accidents at the renovation site.

What does GPR locate?

GPR can locate the following things:

  • Metal/ rebar
  • Plastic
  • Pipelines buried inside concrete
  • Electric cables embedded inside walls
  • Voids inside the concrete.
  • Delamination and corrosion
  • Bedrock
  • And much more.
  • Is GPR better than traditional methods?

    The traditional method of concrete scanning is X-ray. A differentiation between both is given in the table. GPR is a clear winner of this differentiation as it is faster, safer, and more reliable.

    Feature X-ray GPR
    Access Requirements Requires access to both sides of concrete Only needs access to one side of slab
    Health Risks Harmful rays pose risks for testing professional Safe, doesn’t transmit harmful rays.
    Speed of Results Results take time to process Real-time results
    Accuracy Needs improvement More accurate
    Imaging Capacity Provides 2D imaging Can provide 3D scanning capabilities (conditions apply)

    What are the necessary conditions for GPR to work?

    (GPR scanning )works amazingly well, but not every time. It also has some limitations. Understanding the workings of concrete scanning and choosing a trained and experienced testing professional can help you overcome various challenges. Here are a few cases when GPR doesn’t behave well:

    GPR cannot see through metal. When signals from a metal surface reflect, it will not show what exists beneath that metal utility, as radar cannot pass through the metal.

    GPR cannot work in clayey soil. All the signals are absorbed by the soil, and no signals are reflected back. Therefore, GPR is unable to see through the wet soil. Moreover, the choice of antenna, signal frequency, and knowledge of scanning professionals are the other factors that contribute to better results.

    How does GPR ensure safety on a construction site?

    During a coring project: If a coring project is conducted without a GPR scan, there can be many destructive outcomes.

    • The coring device can cut rebar and damage the whole slab.
    • Cutting off electrical cables can cause power outrage.
    • Plumbing pipes can burst and open leakage repair.
    • Snapping of post-tension cables can result in damage to surrounding slabs.
    • However, concrete scanning helps to locate the rebar and other utilities and prevent damage.
    • Void detection: Secondly, scanning helps to detect voids in concrete slabs. Concrete voids make a structure weak and prone to damage. When a coring drill touches a void, it can cause a blast. Using GPR scanning to detect voids and other concrete anomalies ensures the safety of onsite workers and the site itself.

      How do you hire a concrete scanning company?

      Most countries regulate the scanning devices that emit radiation. The device and scanning services must comply with regulations and rules made by authorities. Therefore, you need to hire a contractor who is licensed, insured, and experienced. Focusing on these three qualities keeps you away from any kind of legal issue, onsite damage, or repair.

      Moreover, you need to make sure the company is good with communication and has a good reputation. Make sure to ask your doubts and queries about timing and budget before signing a quote. Hiring the right services is not as easy as searching GPR scanning near me; you will need to be attentive to find a company that meets the above given criteria.

      How is GPR advantageous for your construction project?

      The advantages of GPR scanning include the following things:

      GPR scanning is noninvasive and easy to perform.

      • It offers on-the-spot data interpretation.
      • It is a low-cost method, including device and labor costs.
      • The GPR services are easily available.
      • It provides the highest resolution as compared to other methods.

      Why Concrete Insight?

      Concrete Insight is a trusted GPR scanning service provider in MD. We have served our customers for more than 25 years. We also give concrete core drilling and testing services. Accuracy and precision are our best offerings to our customers. To get a quote from us, Reach out to us now!


      FAQs (Frequently Asked Questions) - GPR Scanning in Construction

      Q1. What is GPR scanning in construction?

      Ans1. GPR scanning, or Ground Penetrating Radar scanning, is a technique used to locate subsurface utilities, including those buried under concrete. It involves transmitting electromagnetic waves into the material and analyzing the reflected pulses to identify discontinuities such as metal or plastic objects, debonding, or delamination.

      Q2. How does GPR work?

      Ans2. GPR scanning operates by emitting electromagnetic signals into the material via a transmitter and receiving the reflected signals with a receiving antenna. The system analyzes the distortions in the received signals to determine the presence and type of buried objects.

      Q3. Why do we need GPR scanning in construction?

      Ans3. GPR scanning is essential in construction for various reasons:

      • Ensuring site safety by detecting buried utilities and abnormalities before construction.
      • Marking precise coring spots for electrical and plumbing work.
      • Locating buried infrastructure in older buildings for renovation purposes, preventing accidents during slab modifications.

      Q4. What does GPR locate?

      Ans4. GPR can locate a range of objects and features including metal/rebar, plastic, pipelines, electric cables, voids inside concrete, delamination, corrosion, and bedrock.

      Q5. Is GPR better than traditional methods like X-ray?

      Ans5. Yes, GPR offers several advantages over traditional methods like X-ray, including faster results, safer operation without harmful rays, real-time data, higher accuracy, and in some cases, 3D scanning capabilities.