This standard specifies the method for determining the velocity of propagation of an ultrasonic pulse in hardened concrete. The results can be used to assess the homogeneity of the concrete, check for the presence of cracks or voids, and evaluate concrete quality, though it does not directly measure strength without correlation.
Specifies the method for determining the ultrasonic pulse velocity in concrete.
Quick Reference Values
Excellent quality concrete velocity> 4.5 km/s
Good quality concrete velocity3.5 to 4.5 km/s
Medium quality concrete velocity3.0 to 3.5 km/s
Doubtful quality concrete velocity< 3.0 km/s
Typical transducer frequency range20 kHz to 150 kHz
Typical pulse repetition frequency20 Hz to 80 Hz
Key Formulas
V = L / T — Pulse Velocity (V) is Path Length (L) divided by Time of Travel (T)
Practical Notes
Surface preparation is critical; ensure a smooth testing surface and use an appropriate couplant (like grease) for good contact between the transducers and the concrete.
The presence of reinforcing steel along the direct pulse path will increase the measured velocity, potentially leading to an overestimation of concrete quality. Always try to test on paths that avoid rebar.
For reliable strength estimation, it is essential to establish a correlation curve between pulse velocity and compressive strength by testing concrete cubes or cores from the same mix (as per Clause 9.3).