Ground Penetrating Radar (GPR) concrete inspection enables you to see into the sub-surface to determine construction detail, identify defects in concrete and locate dangers and hazards.

Concrete is a versatile construction material that can be poured to make complex shapes and forms. This means that unknown or unexpected objects may be concealed within a smooth concrete mass.

The main advantages of GPR as a non-intrusive investigation technique to investigate concrete are threefold:

  1. GPR can locate unknown and hidden hazards such as services, conduits and tanks, thereby identifying suitable and safe areas of concrete to cut and drill.
  2. GPR can determine construction detail, including thickness, map reinforcement detail and locate post-tensioned tendons.
  3. GPR can locate defects, such as delaminations, saturated areas, and voids below concrete slabs.

In this article, we shall look at the first item.

Concrete inspection – locating hidden hazards

Locating hazards in concrete before drilling and cutting operations is essential as it prevents strikes, making the work safe and reducing delays and costs. The following are just a few examples of objects that GPR can detect in concrete:

Services in concrete slabs

Construction professionals working on reinforced concrete slabs on shop or office fit-outs must locate and map services and conduits before drilling, coring or sawing. GPR can trace conduits, and we can map out results in CAD drawings if required.

A GPR Radargram showing a reinforced concrete slab and detected services in the screed layer.
Radargram showing reinforced concrete slab with detected services in screed layer (indicated by blue arrows)

Further reading: Locating services and conduits in concrete slabs.

Tendons in Post-Tensioned Concrete

Post-tensioned tendons are highly stressed elements and mustn’t be damaged. It is of paramount importance that tendons are accurately located before any cutting, coring or drilling works are undertaken in the immediate vicinity.

Further reading: Locating Tendons in Post-Tensioned Concrete.

Hollow Core

It’s not just hazards that need to be located. Sometimes, a contractor needs to identify a sound, solid area of concrete suitable for fixings. A GPR in situ markup survey will easily identify hollow cores, pre-tensioned strands and reinforcement within hollow core precast units.

Two hollow core pre-cast units.
GPR can locate the hollow cores in precast units

Further reading: On-site markup surveys.

Need more information?

Contact us

Contact our GPR experts to learn more about concrete scanning and how our surveys could help you. Our experts will be happy to advise you on the most suitable survey methods for your specific requirements.

Telephone: 0207 565 7056
Email: gpr@sandberg.co.uk