Ultrasonic Pulse Velocity Test

Ultrasonic Pulse Velocity Test is used to assess the quality and strength of in- used to assess the quality and strength of in-situ concrete in structural members.

• It used to check the compaction of concrete, used to check the compaction of concrete, uniformity of concrete, determination of uniformity of concrete, determination of cracks, presence of honeycombs, level of cracks, presence of honeycombs, level of deterioration and also strength estimation deterioration and also strength estimation (qualitatively).

PUNDIT (Portable Ultrasonic Non-Destructive Digital Indicating Tester)

• consists of a pair of transducers (probes) of consists of a pair of transducers (probes) of different frequencies, electrical pulse generator, different frequencies, electrical pulse generator, electrical timing device and cables.

• It is based on the through-transmission It is based on the through-transmission technique.

Portable Ultrasonic Non destructive Digital Indicative Technique Indicative Technique (PUNDIT)

Size: 180 X 110 X 160mm Size: 180 X 110 X 160mm

Weight: 3kg Weight: 3kg

Digital display with Accuracy ±0.1 microseconds Digital display with Accuracy ±0.1 microseconds

METHODS OF TESTING :

1. Direct transmission

2. Indirect transmission

3. Semi-direct transmission

DIRECT TRANSMISSION :

• Pulse velocity will be measured in concrete by Pulse velocity will be measured in concrete by placing placing transducers across transducers across the member exactly the member exactly opposite to each other.

• This is the most appropriate & This is the most appropriate & reliable method reliable method of testing to ascertain the quality / strength of of testing to ascertain the quality / strength of concrete.

INDIRECT TRANSMISSION:

• Pulse velocity will be measured in concrete by Pulse velocity will be measured in concrete by placing transducers on the placing transducers on the same plane same plane of members. of members.

• This is the This is the least reliable least reliable method of testing to method of testing to ascertain the quality / strength of concrete. This ascertain the quality / strength of concrete. This method will be method will be adopted adopted only when there is no other only when there is no other option.

SEMI-DIRECT TRANSMISSION :

• Pulse velocity will be measured in concrete by Pulse velocity will be measured in concrete by placing transducers in planes perpendicular to each placing transducers in planes perpendicular to each other.

• This is a This is a moderately reliable moderately reliable method of testing to method of testing to ascertain the quality / strength of concrete.

Method of calculation of pulse velocity :

Pulse Velocity in concrete will be represented Pulse Velocity in concrete will be represented in Km/sec

Appropriate Appropriate correction factors correction factors to be applied to be applied depending on site condition & factors depending on site condition & factors influencing velocity of pulse. influencing velocity of pulse.

FACTORS INFLUENCING THE VELOCITY OF PULSE IN CONCRETE :

• Type & content of cement

• Influence of reinforcement

• Use of admixtures

• Type & size of aggregates

• Homogeneity & density of concrete Homogeneity & density of concrete

• Age of concrete

• Presence of voids / cavities in concrete Presence of voids / cavities in concrete

• Cracks in concrete

• Curing of concrete, etc.,

Ultrasonic Pulse Velocity Test APPLICATIONS :

• Measurement of concrete uniformity

• Detection of cracking and honeycombing Detection of cracking and honeycombing

• Strength estimation

• Assessment of concrete deterioration

• Measurement of layer thickness

• Measurement of elastic modulus

• Strength development monitoring.

Read More Field Testing