Ferroscan and GPR Rebar Mapping Surveys
Ferroscan and Ground Penetrating Radar (GPR) both offer an effective means of reinforcement detection and imaging within concrete. Sandberg can undertake detailed reinforced concrete investigation and rebar mapping using either Ferroscan or GPR; but which method is better? What are the differences?
Both enable detected rebar to be viewed in a longitudinal section, or as "slices" at different depths. The Ferroscan can provide estimates of rebar diameter, while GPR can provide slab and screed thickness.
Both Ferroscan and GPR data can be downloaded onto a personal computer for further analysis, interpretation and printed output using specialist software provided by the respective manufacturers.
To help you decide which method is more suitable for your specific requirements, we have produced the following table which offers a comparison between the Hilti PS200 Ferroscan and a GSSI SIR3000 GPR system used with a 1.5GHz antenna (based on manufacturers specification and our experience). GPR also has the flexibility of being used with different frequency antennas so better resolution or extra depth can be achieved.
| |
Ferroscan |
GPR |
| Maximum detection depth |
~120mm (20mm diam)
~180mm (36mm diam) |
~450mm |
| Rebar diameter determination |
Yes * |
No |
| Rebar diameter range |
6 - 36mm |
5mm - steel beam |
| Number of rebar layers resolved |
typically 1** |
typically 2** |
| Metal detected |
Ferrous only |
Yes |
| Plastic detected |
No |
Yes |
| Voids detected |
No |
Yes |
| Determine slab thickness |
No |
Yes |
| Determine screed thickness |
No |
Yes |
| Real time rebar location |
Yes |
Yes |
| Single line scan |
Quickscan up to 30m |
Up to ~350m |
| Rebar imaging |
600x600mm area |
Any size |
* Max depth of rebar = 60mm. In our experience the calculated rebar diameter is indicative.
** Depends on rebar spacing and depth
|
