Vibration test ~ a number of electronic tests have been devised,
which include measurement of ultrasonic pulse velocity through
concrete. This applies the principle of recording a pulse at
predetermined frequencies over a given distance. The apparatus
includes transducers in contact with the concrete, pulse generator,
amplifier, and time measurement to digital display circuit. For
converting the data to concrete compressive strength, see BS EN
12504-4: Testing concrete. Determination of ultrasonic pulse
velocity.A variation, using resonant frequency, measures vibrations
produced at one end of a concrete sample against a receiver or
pick up at the other. The driving unit or exciter is activated by a
variable frequency oscillator to generate vibrations varying in
resonance, depending on the concrete quality. The calculation of
compressive strength by conversion of amplified vibration data is
by formulae found in BS 1881-209: Testing concrete.
Recommendations for the measurement of dynamic modulus of
elasticity.Other relevant standards:†BS 1881-122: Testing concrete. Method for determination of water
absorption.
BS 1881-124: Testing concrete. Methods for analysis of hardened
concrete.
BS EN 12390-7: Testing hardened concrete. Density of hardened
concrete.Materials Testing---Concrete