423806464-ULTRASONIC-PULSE-VELOCITY-1-pptx.pdf

upv

1. ULTRASONIC PULSE VELOCITY
(NDT test on concrete)

2. INTRODUCTION
•Ultrasonic pulse velocity test is an in situ, non destructive test
to check the quality of concrete.
•UPV method involves measurement of the time of travel of
electronically generated mechanical pulse through the
concrete.
•Indian standard code for ultrasonic pulse velocity test is IS
13311 (Part 1) : 1992.

3. OBJECTIVES
•The objective of UPV method are :
–Homogeneity of the concrete;
–The presence of cracks, voids and other imperfection (internal
flaws);
–Strength and durability of concrete;
–Change in the structure of concrete;
–The values of elastic modulus of concrete.

4. APPRATUS
•The apparatus for ultrasonic pulse velocity measurement shall
consist of the following :
–Electrical pulse generator
–Transducer –one pair (frequency range between 20kHz to
150kHz)
–Amplifier , and
–Electronic timing devices

5. Image of UPV device
Source: Indiamart.com

7. PRINCIPLE OF UPV
•The ultrasonic pulse is generated by a electronic transducer.
•When pulse is induced into the concrete from a transducer , it
undergoes multiple reflections at the boundaries of different
material phases within the concrete.
•The receiving transducer receive the waves which is fastest
and electronic timing device gives the time of travel of waves.

8. Continue...
•Higher velocities are obtained when the concrete quality in
terms of density, homogeneity and uniformity is good.
•In case of poorer quality lower velocities are obtained.
•If there is crack, void and flaws inside the concrete , it makes
path length longer. Consequently lower velocities are
obtained.

9. INFLUENCE OF TEST CONDITION
•Moisture content of concrete and surface condition.
•Temperature.
•Path length , shape and size of concrete member.
•Stresses.
•Reinforcing bars.

10. PERFORMANCE OF APPARATUS
•The Equipment consist of two transducers, usually in the form
of metal cylindrical heads, one of which is used to transmit an
ultrasonic pulse and the other is a receiver.
•The Transducers are brought into contact with the concrete
surface using a gel or grease.
•They are connected by cable to a control box which contains a
pulse generator, timing circuit and digital display.

11. PERFORMANCE OF APPARATUS
•The digital display indicates the time for the ultrasonic pulse to
travel between the transmitting and receiving transducers.

12. PROCEDURE
•1. Locate the dry location in the concrete structure.
•2. Clean the surface of concrete to remove grits and scales.
•3. Mark grid of size 300mm*300mm on the surface of the
concrete structure.
•4. Measure the distance between the grid points where the
transmitter and the receiver are to be placed.

13. PROCEDURE
•5. Apply grease or petroleum jelly on the grid points so that
probes will get the better contact with the concrete surface.
•6. Press the transmitter and receiver on the predetermined
grid points.
•7. Switch on the ultrasonic pulse velocity meter and the
traverse time on the display is recorded.

14. Techniques of Measuring PV through
Concrete
There are three ways of measuring PV through Concrete:-
1.Direct transmission.
2.Indirect transmission.
3.Surface transmission.

15. Source (Concrete technology : M.S.Shetty)

16. Interpretation of Result
•To determine the quality & homogeneity of the concrete
structures.
•To determine the existence of the flaws, cracks & void in
concrete structures.
•Table: Velocity Criterion for concrete Quality Grading
(IS:13311 Part I).

17. Interpretation of Result