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For most concrete scanning applications, ground penetrating radar (GPR) is the better choice. It is faster, safer, requires access to only one side of the slab, and produces instant on-site results. Concrete X-ray is more accurate in a narrow set of situations, but its radiation hazard, access requirements, and off-site development time make it impractical for most construction and renovation projects. Using the wrong method, or an untrained operator with either method, risks missing post-tension cables, rebar, or conduit before coring or cutting, with consequences that can shut down a job and expose the project to serious liability.
The construction world is often slow to adopt new technologies, even ones that save time, money, and lives.
The ongoing debate between X-ray and ground penetrating radar (GPR) for concrete scanning exemplifies this issue.
Today, GPR provides a safer, faster, and cheaper alternative to X-ray for precision concrete scanning.
- Both GPR and X-ray are non-destructive ways to see inside a concrete slab
- Both can find rebar, conduit, post-tension cables, and other buried hazards
- Both have their advantages and disadvantages
- One has proven itself the superior choice for construction professionals
Let’s dig a little deeper into both technologies, simplify them, and settle the debate once and for all.
Benefits of Concrete Scanning Using Ground Penetrating Radar
Ground penetrating radar scanning is a uniquely effective method of investigating concrete structures. It’s non-destructive, emits no harmful radiation, and requires no prior set-up. This means it can cover large areas quickly and is more cost effective than X-ray.
GPR requires access to only one side of a slab or structure. X-ray requires access to both sides – one side for placing the radioactive material, and the other for placing a receiver.
GPR can penetrate depths of 18-24” depending on the age of the concrete. One important note: fresh concrete contains moisture that GPR may struggle to penetrate, while fully cured concrete is dry and easier to penetrate.
GPR units have advanced in leaps and bounds over the past few decades. Today's scanners are handheld and wireless, fitting anywhere they're needed on a job site and able to transmit their findings directly onto an iPad or other digital device for easier scanning and measuring.
Benefits of Concrete Imaging Using X-Ray
X-ray is effective at providing clear imaging, leaving less room for interpretation than with GPR scanning. The gap between the two technologies continues to narrow as GPR equipment becomes more user friendly. Further, when GPR results are interpreted by a well-trained professional, like a SIM-certified GPRS Project Manager, it closes any significant image-quality gap.
Why Choose GPR over X-Ray for Concrete Imaging?
Ground penetrating radar’s safety, speed, efficiency, accuracy, and cost effectiveness make it the clear choice for precision concrete scanning.
X-ray imaging requires access to both sides of a concrete structure, making it less versatile than GPR scanning. Also, it often requires conducting tests when a facility is shut down to mitigate the risk of irradiating personnel or the public. This is not always feasible for spaces like health centers or manufacturing facilities.
X-ray imaging isn’t only slower to conduct on-site than GPR – it’s also slower to yield results. Modern GPR scanners provide instant data for a skilled technician to interpret. Data collected from an X-ray scan needs to be developed off-site before it can be interpreted.
GPR has fewer limitations than X-ray imaging, and the quality of the results is more than sufficient for most applications. Complementary technologies such as electromagnetic (EM) locating and 3D laser scanning add value to GPR by compensating for some of its limitations.
While GPR is the go-to technology for concrete scanning, the data it collects requires accurate interpretation by a qualified technician.
The GPRS Difference: SIM Training, 99.8% Accuracy, and the Green Box Guarantee
GPRS (Ground Penetrating Radar Systems), the nation’s largest private utility locating company, maintains a 99.8% accuracy rate across more than 300,000 projects. Our elite Project Managers prevent subsurface damage by utilizing advanced technology such as GPR in concert with industry-leading training based on the Subsurface Investigation Methodology (SIM). That’s why GPRS Project Managers can tell you exactly what’s underground, and exactly where those objects are located. This gives you a comprehensive picture of what’s beneath your feet before you ever put a drill or saw to concrete.
It's our confidence in our SIM-qualified Project Managers that led us to introduce the Green Box Guarantee. When we place a Green Box within a layout prior to anchoring or coring concrete, we guarantee that the area will be free of obstructions. If we’re wrong, we pay the cost of the damage.
All concrete scanning findings are stored in SiteMap®, GPRS’s secure infrastructure management platform, giving your team a permanent, accessible record of what’s embedded in your slabs. Contact GPRS to schedule a concrete scan or request a quote.
