Rebar detection and cover mapping

Steel returns the radar pulse instead of passing it, which is what makes reinforcement the easiest target for GPR to resolve reliably. Concrete itself is a low conductivity, low permittivity medium that the pulse travels through with comparatively little loss, so the contrast at a bar is sharp. What varies is not whether the bar shows up, but whether the depth reading is accurate, which depends on calibrating the dielectric constant on the element in front of us rather than assuming a default value for ordinary dry concrete.

Find the reinforcement before the cutter does. Bars and ducts located, clear windows identified, permissible diameter stated at each proposed core position. Grid acquisition in two orthogonal directions, so every bar is confirmed twice rather than assumed from a single pass.

Bar spacing, orientation and cover in plan view, layer by layer, referenced against the nominal cover of IS 456:2000 clause 26.4 rather than an assumed figure. Where the element is congested, echoes from closely spaced bars can merge into one band; the remedy is orthogonal grids and plan view depth slices, not more instrument power, and the report says so where it applies.

The HILTI PS 1000 X-Scan is a three antenna ground penetrating radar system that produces plan view images of concrete, not the single line trace of a covermeter or a rebar scanner. It records a 600 by 600 mm image scan grid in a single set up, extendable to 1200 mm by 1200 mm for larger elements, and detects to a stated maximum of 300 mm in concrete. Default settings assume dry, ordinary concrete, so we acquire in expert mode with the phase of the signal preserved and calibrate the dielectric constant on the element in front of us, processed in PROFIS Detection together with our own MATLAB routines.

Enquiry. Send the element type, thickness, exposure condition and what you need to locate on WhatsApp. Photographs, drawings and any previous scan output help us assess it fast.

Plan. We check access, moisture, exposure and reinforcement congestion against your target, confirm radar is the right test, and schedule the visit.

Scan and mark. Calibrated on the element, scanned in an orthogonal grid, and marked directly on the surface for your coring or cutting crew, same visit.

Report, if needed. Depth slices, plan extents and permissible core diameters, issued as a written report when your project requires formal documentation.