Old School Ultrasonic Pulse Velocity

Ultrasonic pulse velocity has been around for many years, as a means of assessing many materials, including concrete for flaws such as voids and cracks.? Simplistically, ultrasonic pulses will travel through solid materials with varying velocities, dependent upon the density of the material.? However, pulses will not jump across cracks or voids, where possible deviating around them.? Once calibrated on a specific concrete we can therefore use the transit times through a known path to assess for the presence of such flaws and estimate their approximate size and extent.?

In this case, CRL Surveys were commissioned to assess the concrete forming an overflow chamber in the Scottish Borders.? In 1890 a 35mile long tunnel was driven to connect a reservoir to a large city waterworks, the water siphoning up and down across the valleys at a rate of 27million gallons per day.? Within one valley an overflow chamber had been constructed from in-situ mass concrete, with walls 900mm thick.

Over the years, the concrete had cracked, worsening to the point when remediation was needed.? CRL Surveys were commissioned to evaluate the extents of deterioration, which in this case included ultrasonic pulse velocity to assess the extents of cracking through the thickness of the walls.

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