NON DESTRUCTIVE TEST (NDT) SAURABH GUPTA BLOG - http://notescivil.blogspot.in/ After this seminar you will able to answer the following Non- destructive testing Rebound hammer testing Ultrasonic pulse velocity test Cover test methods including principle, advantages and point of action NDT Technique to test new or old concrete structure with respect to its strength and durability ,without or partial damage to a small part of concrete. It doesn’t estimate ultimate or yield strength of concrete. It is easy mechanized method, and is very cost effective , many test can be performed at the same cost of single destructive test. No sample is required to collect for the laboratory testing as compare to some methods destructive testing TEST Rebound Hammer Test Windsore Probe Testing Ultrasonic Pulse Velocity Test Acoustic Emission Method Pulse Echo Method Initial Surface Absorption Test Radar Technique Infrared Thermography Quantab Test Carbonation test Profometer / Rebar locator REBOUND HAMMER TEST (IS 13311 II) Determination of strength and hardness of concrete. ULTRASONIC PULSE VELOCITY TEST (IS 13311 I) To determine the homogeneity, compatibility and cracks or void if present . PROFOMETER / REBAR LOCATOR Location of bar and diameter of bar CARBONATION TEST To estimate the amount of carbon and corrosion estimation. To assess the likely compressive strength of concrete with help of with suitable co-relations between rebound index and compressive strength. To assess the uniformity of concrete. To assess the quality of concrete in relation to standard requirements. To assess the quality of one element of concrete in relation to another This method can be used with greater confidence for differentiating between the questionable and acceptable part of a structure or for relative comparison between two different structure. When the plunger of rebound hammer is pressed against the surface of concrete, the spring control mass rebounds and the extent of such rebound depend upon the surface hardness of concrete, the rebound is thus related with compressive strength of concrete and the graduated scale is designated as rebound number It Consists of spring controlled mass that slides on a plunger within a tubular housing. The impact energy required for rebound hammer for different application is different (shown in table in next slide) Rebound hammer is used to check – 1 Compressive strength of concrete 2 Uniformity of concrete 3 Quality of element of concrete Ultrasonic pulse velocity test To assess the uniformity and homogeneity of concrete. To assess the quality of concrete in relation of standard requirement. Detection of presence of voids, cracks & imperfection of concrete. Measurement of changes occurring with time in the properties of concrete. To overcome all these problems, the methods have been developed for investigation and evaluation of concrete st

1. HEALTH CHECK OF STRUCTURE
“Engineering is not only study of 45 subjects but it
is moral studies of intellectual life.”
NON DESTRUCTIVE TEST
(NDT)

2. • After this seminar you will able to
answer the following
 Non- destructive testing
 Rebound hammer testing
 Ultrasonic pulse velocity test
 Cover test
methods including principle, advantages and point of
action

3. Concrete
Testing
Destructive
Non
Destructive

4. • NDT
1. Technique to test new or old concrete structure with
respect to its strength and durability ,without or partial
damage to a small part of concrete.
2. It doesn’t estimate ultimate or yield strength of concrete.
3. It is easy mechanized method, and is very cost effective ,
many test can be performed at the same cost of single
destructive test.
4. No sample is required to collect for the laboratory testing as
compare to some methods destructive testing

5. OUTPUT OF NDT
ELASTIC
MODULUS
REINFORCEMENT
LOCTAION
QUALITY OF
WORKMANSHIP
DENSITY STRENGTH
SURFACE
HARDNESS
CRACKS AND
VOIDS
SURFACE
ABSORPTION
LIFE PERIOD

6. Sno. TEST
1 Rebound Hammer Test
2 Windsore Probe Testing
3 Ultrasonic Pulse Velocity Test
4 Acoustic Emission Method
5 Pulse Echo Method
6 Initial Surface Absorption Test
7 Radar Technique
8 Infrared Thermography
9 Quantab Test
10 Carbonation test
11 Profometer / Rebar locator

7. • REBOUND HAMMER TEST (IS 13311 II)
Determination of strength and hardness of concrete.
• ULTRASONIC PULSE VELOCITY TEST (IS 13311 I)
To determine the homogeneity, compatibility and cracks or
void if present .
• PROFOMETER / REBAR LOCATOR
Location of bar and diameter of bar
• CARBONATION TEST
To estimate the amount of carbon and corrosion estimation.

8. • To assess the likely compressive strength of concrete
with help of with suitable co-relations between rebound
index and compressive strength.
• To assess the uniformity of concrete.
• To assess the quality of concrete in relation to standard
requirements.
• To assess the quality of one element of concrete in
relation to another
• This method can be used with greater confidence for
differentiating between the questionable and acceptable
part of a structure or for relative comparison between two
different structure.
SOURCE - IS13311 PART II
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9. Rebound hammer test contd..
Source - www.humboldtmfg.com
SOURCE – Concrete Technology by M H Sheety

10. Rebound hammer test contd..
When the plunger of rebound hammer is pressed against the surface of concrete,
the spring control mass rebounds and the extent of such rebound depend
upon the surface hardness of concrete, the rebound is thus related with
compressive strength of concrete and the graduated scale is designated as
rebound number
It Consists of spring controlled mass that slides on a plunger within a tubular
housing.
The impact energy required for rebound hammer for different application is
different (shown in table in next slide)
REF - IS13311 PART II

11. Rebound hammer test contd..
Sno Applications Impact energy (Nm)
1 Normal weight concrete 2.25
2 Light weight concrete or sensitive
part of concrete
0.75
3 Mass concrete ex- Road payment ,
hydraulic structure
30.00
SOURCE – youtube.com

12. Rebound hammer test contd..
SOURCE – Concrete Technology by M H Sheety

13. Rebound hammer test contd..
REF – Concrete Technology by M H Sheety
AVG
REBOUND NO.
QUALITY OF
CONCRETE
>40 Very good hard layer
30-40 Good layer
20-30 Fair
<20 Poor concrete
0 Delaminated
Rebound hammer is used to check –
1 Compressive strength of concrete
2 Uniformity of concrete
3 Quality of element of concrete
Limitation –
1 Accuracy ± 25%
2 Only suitable for closed textured conc.
3 Partially compacted concrete has no relation with
rebound index
4 Result affected by angle of test, surface
smoothness and mix proportion.

14. Rebound hammer test contd..
Relation between
rebound
number and
compressive
strength
REF – Concrete Technology by M H Sheety

15. Question ?
1. What are the factors affecting the
Rebound hammer test result ?

16. • To assess the uniformity and homogeneity of
concrete.
• To assess the quality of concrete in relation of
standard requirement.
• Detection of presence of voids, cracks &
imperfection of concrete.
• Measurement of changes occurring with time in
the properties of concrete.
• To compare quality of two different concrete
element.
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REF- IS 13311 Part I

17. IMAGE SOURCE www.spectro.in
UPV test contd..
IMAGE SOURCE - theconstructor.org/

18. UPV test contd..
Pulse velocity tests measure the transit time of an ultrasonic pulse between two
transducers, a transmitter and a receiver. The velocity of the pulse can be
determined from the transit time and the distance between the transmitter and
the receiver. The equation for the calculation of pulse velocity is:
The pulse velocity measurement set consists of a pulse generator, a transmitter, a
receiver, an amplifier, a circuit that measures the elapsed time, a time display
unit, and connecting cables. Note that the pulse generator, receiver, amplifier,
timing circuit, and time display unit are all incorporated in the velocity meter
shown in the schematic diagram of the pulse velocity measurement set
REF - IS13311 PART I

19. UPV test contd..

20. There are three ways in which the transducers may be arranged, as shown in
Figure :
(a) direct transmission through opposite faces
(b) semi-direct transmission through adjacent faces
(c) indirect transmission at the same face.
INTERPRETATION OF TEST RESULT :
UPV test contd..

21. UPV test contd..
• Smoothness of contact surface under
test
• Influence of path line of pulse velocity
• Temperature of concrete
• Moisture content of concrete
• Presence of reinforcement steel
• Stress level in concrete

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• To determine
1. Diameter of reinforcement
2. Location of R/F
3. Cover

23. Rebar locator test contd..
The instrument is based upon measurement of change of an electromagnetic field
caused by steel embedded in the concrete.
Adequate cover to reinforcement is required in any reinforced concrete
structure to prevent corrosion and to improve durability of structure. To
calculate actual strength of concrete structures, the number of reinforcing bars,
their condition of corrosion, cover to reinforcement, and grade of concrete is
required. In the case of old structures, when the detailed drawings are not
available, it becomes very difficult to compute the strength of the structure
which is required for the strengthening scheme of the structure. Sometimes,
the strength of concrete structures are to be checked to permit higher load and
in absence of reinforcement details it becomes very difficult to take a decision.

24. Rebar locator test contd..
To overcome all these problems, the methods have been developed
for investigation and evaluation of concrete structures. Profometer
is a small versatile instrument for detecting location, size of
reinforcement and concrete cover. This instrument is also known
as rebar locator. This is a portable and handy instrument which is
normally used to locate the reinforcement on LCD display. This
instrument is available with sufficient memory to store measured
data. Integrated software is loaded in the equipment for carrying
out and printing statistical values.
The equipment is quite handy and weighing less than two kgs. It works
on normal batteries and thus does not require any electrical
connection.

25. Advantages
Rebar locator test contd..
This is a purely non-destructive test for evaluation of concrete structures
particularly old structures. The methods is very fast and gives quite
accurate results if the reinforcement is not heavily congested. The
equipment is very light and even one person can perform the test without
any assistance.
Factor affecting test methods
• Cover measurement may be affected by neighboring bars parallel to the
bras being measured.
• Magnetic effects from the aggregate and matrix of the concrete.
• Variation in the properties of steel.
• Cross sectional shape of bars.
• Roughness of surface .

26. THANK YOU