Ground Penetrating Radar (GPR) is a safe, extremely fast, and accurate tool we use to locate materials within a concrete structure.
GPR emits electromagnetic energies through a concrete slab, and this energy travels until it hits an object within the concrete. A majority of the energy is reflected off the object and is then returned to an antenna receiver. The amount of signal return is dependent on the object’s dielectric make-up; the higher the dielectric constant, the higher return of signal. Older concrete and plastics generally have a low dielectric constant and a low signal return, while steel, water, and mineral-rich mediums have a high dielectric constant and a higher return of signal.
Radar can help reduce the time and money spent on a project because they only require access to one side of the concrete, and we can cover more ground quickly in a project with a radar.
However, with radar, what you’re seeing in the images isn’t always evident, and steel rebar and post-tension cables can both easily be seen. It’s often hard to distinguish between the two.
In many of our jobs, we use X-ray and GPR together in order to form the most complete picture, and our top priority is safety and doing the job fully and correctly. We won’t do a job with radar just because it’s faster or cheaper if an X-ray is truly needed to fully assess the situation inside the concrete.