Core Technology
GPR Concrete Scanning
Ground penetrating radar is the industry-standard, non-destructive method for locating embedded services, reinforcement, and structural elements within concrete. KCT Scan delivers professional GPR scanning services across South East Queensland and Northern New South Wales.
The Technology
What is GPR Scanning?
GPR stands for Ground Penetrating Radar. It is a geophysical technique that uses short pulses of electromagnetic energy to image the internal structure of concrete, soil, rock, and other materials. In the context of concrete scanning, GPR allows us to see what is embedded inside a slab, wall, or structural element without cutting into it or causing any damage.
The GPR antenna is moved across the concrete surface, sending radio-frequency pulses into the material. When these pulses encounter a boundary between materials of different density or electrical properties, such as the boundary between concrete and a steel reinforcement bar, part of the energy reflects back to the antenna. The time it takes for the reflection to return tells us the depth of the object, and the strength and shape of the reflection helps us identify what the object is.
This entire process happens in real time. As the technician moves the GPR unit across the surface, a cross-sectional image of the concrete builds on screen, revealing rebar, cables, conduits, pipes, voids, and other features hidden beneath the surface. The results are immediate, there is no waiting for laboratory processing or film development.
Electromagnetic Pulses
GPR uses safe, low-power radio waves. No ionising radiation, no health risk, no evacuation zones required.
Completely Non-Destructive
The antenna sits on the concrete surface and scans without making any mark, hole, or alteration to the structure.
Real-Time Results
Data is displayed and interpreted on-site as scanning progresses. No laboratory processing or waiting period.
Capabilities
What Can GPR Detect?
Ground penetrating radar detects a wide range of embedded objects and structural conditions within concrete. Here is what our GPR concrete scanning services can identify for your project.
Reinforcement Steel (Rebar)
GPR concrete scanning accurately locates reinforcement steel bars within concrete slabs, walls, and structural elements. Our ground penetrating radar equipment maps rebar position, depth, and spacing so you know exactly what lies beneath the surface before any cutting or coring works begin.
Post-Tension Cables
Post-tension cables carry enormous force within concrete structures. Striking one during drilling or cutting can cause catastrophic structural failure and serious injury. GPR scanning detects these cables and maps their paths, allowing you to plan penetration points safely.
Electrical Conduits
Embedded electrical conduits running through concrete slabs and walls are invisible to the naked eye. Our concrete GPR equipment identifies conduit runs and their approximate depth, helping you avoid live electrical services and the costly damage that comes with hitting them.
Water & Gas Pipes
Plumbing and gas services embedded in or beneath concrete can be difficult to locate without specialised equipment. Ground penetrating radar detects metallic and non-metallic pipes within concrete, reducing the risk of flooding, gas leaks, and expensive remediation work.
Voids & Delamination
GPR scanning identifies internal voids, honeycombing, and areas of delamination within concrete structures. These defects can compromise structural integrity and are impossible to detect visually. Early identification through GPR allows for targeted repair before problems escalate.
Slab Thickness
Ground penetrating radar measures concrete slab thickness without the need for destructive testing. This is essential for structural assessments, renovation planning, and verifying that construction meets engineering specifications and Australian standards.
The Process
How GPR Scanning Works
Understanding how ground penetrating radar works helps you appreciate why it is the preferred method for concrete scanning on construction sites across Australia.
Surface Preparation
The scanning area is cleared and prepared. Our technician positions the GPR antenna on the concrete surface. No special access requirements, barricades, or evacuation zones are needed, unlike X-ray scanning methods.
Signal Transmission
The GPR unit sends short pulses of electromagnetic energy into the concrete. These radio-frequency pulses travel through the slab at a known velocity, penetrating to depths of up to 400mm or more depending on concrete composition and reinforcement density.
Signal Reflection & Capture
When the electromagnetic pulses encounter a change in material density, such as rebar, a conduit, a post-tension cable, or a void, part of the signal reflects back to the antenna. The GPR unit records the time and amplitude of each reflection, building a detailed cross-sectional profile of the concrete.
Interpretation & Marking
Our experienced technician interprets the GPR data in real time, identifying embedded objects by their characteristic signal patterns. Results are marked directly on the concrete surface, giving you an immediate, practical output you can use to plan your works safely.
The entire GPR scanning process is completed on-site with immediate results. Unlike laboratory-based testing methods, there is no waiting period for results. Our technician marks findings directly onto the concrete surface as they scan, giving your team a clear, practical visual guide to work from. For projects requiring formal documentation, we provide detailed written reports with annotated images and depth measurements.
Comparison
GPR vs X-Ray Scanning
While both GPR and X-ray can image the interior of concrete, GPR scanning offers significant practical advantages for most concrete scanning applications. Here is how the two methods compare.
Feature
GPR Scanning
X-Ray Scanning
Radiation Exposure
No radiation whatsoever. GPR uses safe, low-power radio waves similar to Wi-Fi signals.
Requires ionising radiation. Area must be evacuated and barricaded during each exposure.
Site Access
Single-side access only. Scan from one surface of the slab or wall without needing access to the other side.
Requires access to both sides of the element. One side for the source, the other for the film.
Speed
Real-time results. Large areas can be scanned quickly and continuously without waiting for film development.
Each shot covers a small area. Film must be developed, making the process significantly slower.
Outdoor Use
Works effectively outdoors in all weather and lighting conditions.
Difficult to use outdoors due to radiation safety exclusion zones and film handling requirements.
Cost
Generally more cost-effective, especially for large scanning areas and multiple penetration points.
Higher cost due to radiation safety requirements, exclusion zones, and slower setup times.
Safety Requirements
No special safety requirements. Other trades can continue working in the immediate area.
Requires a licensed radiation operator, exclusion zones, and cessation of other works in the vicinity.
When is X-Ray Still Preferred?
X-ray scanning produces a highly detailed image similar to a medical X-ray and can be preferable when you need to clearly distinguish between closely spaced objects or when the very highest level of detail is required for a critical penetration. However, for the vast majority of concrete scanning applications including drill clearance, rebar location, and general slab surveys, GPR scanning is the faster, safer, and more cost-effective choice. Our team will advise you if X-ray would be more appropriate for your specific situation.
Applications
Where GPR Concrete Scanning is Used
From small residential renovations to large-scale infrastructure projects, GPR scanning is an essential step before any penetration works in concrete.
Residential Projects
- Bathroom and kitchen renovations requiring core holes through slabs
- New plumbing and electrical penetrations in existing homes
- Extensions and additions connecting to existing structures
- Pool installations adjacent to existing foundations
- Structural assessment before removing internal walls
Commercial & Industrial
- Office fitout and refurbishment works
- Mechanical and electrical service installations
- Structural assessment of existing buildings
- Warehouse and factory floor modifications
- Retail tenancy alterations and new service connections
Infrastructure & Civil
- Bridge deck assessment and condition surveys
- Road and pavement thickness verification
- Tunnel lining inspection and assessment
- Water and wastewater treatment facility upgrades
- Retaining wall and structural element surveys
Coverage
GPR Scanning Service Areas
KCT Scan provides professional GPR concrete scanning services across South East Queensland and Northern New South Wales. We cover all major regions and are happy to discuss projects outside our standard service area.
Gold Coast
Southport, Surfers Paradise, Burleigh, Robina, Coolangatta, and surrounds
Brisbane
CBD, Inner suburbs, South Brisbane, Fortitude Valley, and surrounds
North Brisbane
Chermside, Aspley, Strathpine, Redcliffe, Caboolture, and surrounds
Sunshine Coast
Maroochydore, Caloundra, Noosa, Nambour, and surrounds
Ipswich
Ipswich CBD, Springfield, Goodna, Redbank, and surrounds
Logan
Logan Central, Springwood, Beenleigh, Browns Plains, and surrounds
Not listed above? We regularly travel to sites across Northern NSW including Tweed Heads, Byron Bay, Lismore, and surrounding areas. Contact us to discuss your project location.
FAQ
Frequently Asked Questions About GPR Scanning
What is GPR concrete scanning?
GPR concrete scanning is a non-destructive testing method that uses ground penetrating radar technology to see inside concrete without cutting or drilling. A GPR unit sends electromagnetic pulses into the concrete surface. When these pulses hit an embedded object such as rebar, a post-tension cable, or a conduit, part of the signal reflects back to the antenna. The reflected signals are displayed on screen in real time, allowing our technician to identify and mark what is hidden within the concrete. It is the industry standard method for scanning concrete before any cutting, coring, or drilling works.
How deep can GPR scan into concrete?
In typical concrete conditions, our GPR equipment can scan to depths of approximately 300 to 400 millimetres. The actual depth of penetration depends on several factors, including the density of the concrete, the amount and spacing of reinforcement, moisture content, and the frequency of the GPR antenna being used. For most residential and commercial slabs, this depth is more than sufficient to identify all embedded services and reinforcement. If deeper penetration is required for specific applications, we can discuss alternative approaches.
Is GPR scanning safe? Does it use radiation?
GPR scanning is completely safe and does not use any ionising radiation. Ground penetrating radar works by emitting low-power electromagnetic pulses, similar in principle to the radio waves used by Wi-Fi routers and mobile phones. There is no health risk to the operator, site workers, or building occupants. Unlike concrete X-ray scanning, GPR requires no evacuation zones, radiation permits, or special safety procedures. Other trades can continue working in the immediate area while scanning is underway.
How accurate is GPR concrete scanning?
GPR concrete scanning is highly accurate for locating embedded objects. In favourable conditions, our equipment can determine the horizontal position of reinforcement and services to within approximately 10 to 20 millimetres. Depth measurements are typically accurate to within 10 percent of the actual depth. However, accuracy can be influenced by factors such as concrete composition, reinforcement density, and signal interference. Our experienced technicians understand these variables and will advise you on the confidence level of results for your specific situation.
How long does GPR scanning take?
The time required depends on the scope of the project. A single core hole clearance typically takes 15 to 30 minutes. Scanning a typical residential slab area for a renovation project might take one to two hours. Larger commercial projects with extensive scanning requirements may take half a day or a full day. One of the key advantages of GPR over X-ray scanning is speed. GPR provides real-time results without waiting for film development, and large areas can be scanned continuously rather than one small exposure at a time.
What is the difference between GPR scanning and cover meter scanning?
GPR scanning and cover meter (electromagnetic) scanning are complementary technologies, and we often use both on a single project. Cover meters use electromagnetic induction to detect ferrous (iron-based) metals such as reinforcement steel. They are very accurate for measuring concrete cover depth and rebar spacing but cannot detect non-metallic objects such as plastic conduits or PVC pipes. GPR, on the other hand, detects changes in material density and can identify both metallic and non-metallic objects, including post-tension cables, plastic pipes, voids, and changes in slab thickness. For comprehensive scanning, using both technologies together provides the most reliable results.
Part of the KCT Group
Need Concrete Testing Services?
KCT Scan is part of the KCT Group. In addition to GPR concrete scanning, our sister company KCT provides comprehensive concrete testing services including compressive strength testing, slump testing, and compliance verification across South East Queensland and Northern New South Wales.
Visit kct.net.auNeed GPR Concrete Scanning?
Get in touch with KCT Scan today for a quote. Our experienced team is ready to help with your next project across SE QLD and Northern NSW.