Rebar location for coring in a difficult mix

Cores were needed through structural elements. Standard scanning had already been tried and produced nothing the client engineers were prepared to cut on. A wrong call meant a severed main bar and a structural repair.

The concrete used a fine aggregate of non standard mineralogy. That changes the electromagnetic behaviour of the mix, not its strength: higher attenuation, slower pulse, and far more scatter off the matrix itself. Aggregate returns competed with bar returns, so the image had no usable contrast.

Recalibrated the dielectric constant on this mix using a bar of known cover, then reacquired in grid mode so every bar was confirmed in two directions. Processing used our own parameter set for noisy matrices: narrowed filter band, background removal, and gain fitted to the measured attenuation rather than a default ramp. Reinforcement then resolved layer by layer in plan view.

Bars marked with depths, core positions set out in the clear windows between them, permissible core diameter stated at each. No reinforcement cut.

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.