Procedure:

i. Ultrasonic pulse velocity method consists of measuring the time travel of an ultrasonic pulse passing through the concrete to be tested.

ii. The pulse generated circuit consists of electronic circuit for generating pulses and a transducer for transforming these electronic pulses into mechanical energy having vibration frequency in the range of 15 to 50 kHz.

iii. The time travel between the initial path and the reception of the pulse is measured electronically.

iv. The path length between transducer divided by the time of travel gives the average velocity of the wave propagation. PUNDIT (Portable Ultrasonic Non Destructive Digital Indicating Tester) is a battery operated fully digitized instrument which is generally used for measuring ultrasonic pulse velocity.

Techniques of measuring Pulse velocity through concrete :

a) Direct transmission: The transmitting and receiving transducers are placed on opposite surfaces of the concrete slab. This will give maximum sensitivity and provide a well-defined path length

b) Indirect transmission: The transmitting and receiving transducers are placed on adjacent surfaces of the concrete slab.

c) Surface transmission: The transmitting and receiving transducers are placed on same surfaces of the concrete slab