How far the corrosion had gone

The client needed the extent of reinforcement corrosion in an RCC jetty in continuous contact with saline water, across submerged, tidal, splash and atmospheric zones.

This is the worst case for radar. Chloride in the pore solution drives conductivity up and absorbs the pulse. High free water content drives the dielectric constant up and displaces every depth reading. Both change with height above water on the same pile. A standard set up closes the detection window above the reinforcement exactly where deterioration is worst.

Expert mode from the outset, with parameters derived per exposure zone rather than per structure, filters set to keep the low end of the band that survives in conductive concrete, and phase preserved. Our MATLAB routines then classified each element face into three separate conditions: corroding bars, shown by localised loss and broadening along the bar line, delamination, shown by a flat air type reflector with repeats, and disintegrated concrete, shown by incoherent high scatter zones with no ordered bar pattern at all.

The three conditions mapped separately, so repair could be specified proportionately, whether patch repair, cover replacement or reconstruction, instead of applying the costliest remedy everywhere. Chloride profiling and half cell potential testing to ASTM C876 were recommended at a small number of agreed locations for quantitative confirmation.

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.