Nondestructive testing (NDT) is the process of inspecting, testing, or evaluating materials, components or assemblies for discontinuities, or differences in characteristics without destroying the serviceability of the part or system.

1. NON-DESTRUCTIVE TESTING (NDT)

2. NEED FOR TESTING :
material
• Monitoring long-term changes in
properties and structural performance.
• To check for the workmanship.
• For remedial schemes and repairs.
• To check for design specification.

3. TESTING
NON-
DESTRUCTIVE
SEMI / PARTIAL DESTRUCTIVE TEST
DESTRUCTIVE
TYPES OF TESTING

4. DESTRUCTIVE TESTING
• Destructive testing (DT) is a form of object analysis.
• Involves applying a test to break down a particular
material/sample.
• It determine its physical properties, such as the mechanical
properties of strength, toughness, flexibility, and hardness.
• Examples:- Compression Testing, Flexural Testing ,
Crushing Strength etc.

5. NON-DESTRUCTIVE TESTING
• NDT is cost effective & reliable technique to evaluate
properties of a material, component, structure or
system for characteristic defects and discontinuities
analysis without causing damage to the original part.
• The quality of product in the field is checked by non-
destructive methods.
• Examples:- Ultrasonic Pulse Velocity, Rebound
Hammer, Carbonation etc.

6. SEMI/PARTIAL DESTRUCTIVE TESTING
• The semi-destructive testing of concrete is that, under
the prerequisite that the bearing capacity of the
structure to be tested is subjected to no affection.
• partial destructive testing is directly made on the
structural concrete or, the characteristic strength as the
testing result can be transformed directly from the
measurements of the sample.
• Examples:- Core Sampling Method, Extracting Method,
Separating Method, Shooting Method etc.

7. IMPORTANCE OF NDT
• To accident prevention and to reduce cost
• For routine or periodic determination of quality of the
plants and structures during service.
• To determine acceptance to a given requirement
• To give information on repair criteria
• To ensure the safety of operation
• To control manufacturing processes and lower
manufacturing costs.

8. Advantages of NDT :
Reusable
Safe
Accurate
Cost effective
Quality control
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9. DELIVERABLES OF NDT

10. MARKET OF NDT
• NDT Market is estimated to grow at a CAGR of 3.5% to reach
the worth $1720.96 Million by 2020.
• Major Revenue Generating Regions –U.S. And Europe.
• Latin America and Asia-Pacific are emerging market.
• Brazil, India and China have immense growth potential for
NDT.

11. • Visual Testing
• Ultrasonic Testing
• Rebound Hammer Test
• Acoustic Emission Testing
• Corrosion Assessment Test
• Carbonation Test.
• Bar Locater and Cover Meter
• Liquid Penetrant Testing
• Electro-Magnetic Testing
• Thermography Testing
• Radiograph testing
NDT TESTING METHODS
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12. • Visual testing also known as visual inspection or Optical testing is one of the
most common techniques which involve the operator looking at the test piece.
• This can be aided by the use of optical instruments such as magnifying
glasses or computer assisted systems (known as “Remote viewing”)
• This method allows for the detection of corrosion,misalignment, damage,
cracks and more…
• Visual testing is inherentin most other types of NDT as they will generally
require an operator to look for defects.
VISUAL TESTING

13. PRINCIPLE :
• The basic procedure used in visual NDT involves illumination of test specimen
with light, usually in the visible region.
• The specimen is then examined with eye or by light sensitive device such as photo
cells. The surface of the specimen should be adequately cleaned before being
inspected.
Environment for Visual Inspection :
• Inspection must take place in a clean, comfortable environment with adequate
lighting. Lighting is very important and can greatly affect the results.
• It included natural daylight, Bright sunlight and Artificial light.
VISUAL TESTING

14. Types of Visual Inspection :
 Unaided Visual Inspection
 Aided Visual Inspection
(a) Unaided Visual Inspection : It is also known as direct visual inspection.It can be
accomplished with the help of naked eye. It can do without the help of optical aids.
Defects can be detected are : Absence of cracks, Corrosion layer, Surface porosity,
Misalignment of mated parts.
Aids of Unaided Visual Inspection : THE EYE – Human eye the most valuable NDT tool.
Sensitivity of the human eye varies according to the light source.
Human eye has an excellent visual perception. Yellow green light of wavelength 5560oA is the
most suitable light for human eye at normal condition.
VISUAL TESTING

15. • It is also known as indirect visual inspection. It can do with the help of optical
aids.
Ex: Videoscope, Advanced videoscope, Borescopes, Microscope, Magnifying
glass.
Types of aided viewing is :
(i) Direct viewing – Viewing of an object in the operators immediate presence.
This can be unaided or by using equipment.
(ii) Remote viewing – Viewing of an object not in the operators immediate
presence. This can only be done using special equipment.
(b)Aided VisualInspection

16. The commonly using visual aids are,
Magnifying glass,Fillet weld gauge,Microscope, Computer equipment (remote viewing), Illuminated
magnifier, Holography,Borescope,Magnifying mirrors, Periscope,Endoscope.

17. MATERIAL FACTORS THATAFFECT VISUAL TESTING
 Surface
condition
Cleanliness
Colour
Texture
 Physical conditions
Specimen
condition
Shape and size
Temperature
VISUAL TESTING
 Environmental factors
Atmosphere
Humidity and
temperature Safety
 Physiological factors
Physical comfort
Health, mental attitude,
fatigue and test item position

18. Advantages :
 Simple method to perform
 Examination can be performed
quickly
 Low cost method
 Minimal training
 Minimal equipment
 Speed, Field mobility
 Applicability to irregular shapes
VISUAL TESTING
Disadvantages :
 Inspector training necessary
 Good eyesight required (or) eyesight corrected to
20/40
 Can miss internal defects
 Report must be recorded by inspector
 Open to human error
 Visual testing is sometimes limited to component
geometry: Size, contour, surface roughness,
complexity, and discontinuity orientation
Applications :
• Examining the surface condition of a
component
• Examining alignment of mating surfaces
• Checking presence of leaks

19. ULTRASONIC PULSE VELOCITY TEST
• used to assess the quality and strength of in-
situ concrete in structural members.
• used to check the compaction of concrete,
uniformity of concrete, determination of
cracks, presence ofhoneycombs, level of
deterioration and also strength estimation
(qualitatively).

20. PUNDIT (Portable Ultrasonic Non-Destructive Digital
Indicating Tester)
• Consists of a pair of transducers (probes) of
different frequencies, electrical pulse generator,
electrical timing device and cables.
• It is based on the through-transmission technique.

21. Portable Ultrasonic Nondestructive Digital
Indicative Technique (PUNDIT)
Size: 180 X 110 X 160mm
Weight: 3kg
Digital display with Accuracy ±0.1 microseconds

22. METHODS OF TESTING :
1. Direct transmission
2. Indirect transmission
3. Semi-direct transmission

23. DIRECT TRANSMISSION :
• Pulse velocity will be measured in concrete by
placing transducers across the member exactly
opposite to each other.
• This is the most appropriate & reliable method of
testing to ascertain the quality / strength of
concrete.

24. DIRECT TRANSMISSION OF PULSEACROSS R.C BEAM

25. DIRECT TRANSMISSION OF PULSE INR.C COLUMN

26. INDIRECT TRANSMISSION :
• Pulse velocity will be measured in concrete by placing
transducers on the same plane of members.
• This is the least reliable method of testing to ascertain
the quality / strength of concrete. This method will be
adopted only when there is no other option.

27. INDIRECT TRANSMISSION OF PULSE IN R.C.DECK

28. SEMI-DIRECT TRANSMISSION :
• Pulse velocity will be measured in concrete by placing
transducers in planes perpendicular to each other.
• This is a moderately reliable method of testing to
ascertain the quality / strength of concrete.

29. SEMI-DIRECT TRANSMISSION OF PULSE IN R.C.DECK

30. Method of calculation of pulse velocity :
Velocity = (Distance travelled / Path length)
Time taken
Pulse Velocity in concrete will be represented
in Km/sec.
Appropriate correction factors to be applied
depending on site condition & factors
influencing velocity of pulse.

31. Pulse Velocity
(kM/sec)
Below 3.0
3.1 to 3.5
3.5 to 4.5
Above 4.5
Concrete Quality
Grading (as per IS:13311
(Part-1)-1992)
Doubtful
Medium
Good
Excellent
QUALITY GRADING CHART :

32. 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
Age of concrete
Presence of voids / cavities in concrete
Cracks in concrete
Curing of concrete, etc.,

33. •
•
•
•
•
Measurement of concrete uniformity Detection
of cracking and honeycombing Strength
estimation
Assessment of concrete deterioration
Measurement of layer thickness
Measurement of elastic modulus
Strength development monitoring.
APPLICATIONS :

34. REBOUND HAMMER TEST :
• It is a quick method for assessing the quality of
concrete based on surface hardness indicated by the
Rebound number.
• An higher rebound value indicates the higher
strength / surface hardness of concrete.
• This equipment works based on the spring
controlled hammer slides on a plunger within a
tubular housing.

35. Figure: Rebound Hammer.
Weight < 2Kg
Impact Energy = 2.2Nm
Suitability 20 – 60 MPa

36. Figure: Testing by Rebound Hammer

37. METHODS OF TESTING :
Depending on the position of the rebound hammer
1. Horizontal
2. Vertically upwards
3. Vertically downwards
4. Inclined vertical upwards
5. Inclined vertical downwards

38. POSITION OF REBOUND HAMMER -VERTICAL UPWARDS

39. POSITION OFREBOUND HAMMER - VERTICAL
DOWNWARDS

40. METHOD OF CALCULATION :
•Average rebound number will be calculated
after exclusion of freak values and applying
necessary correction factor for position of
Rebound Hammer.
•To evaluate the strength of concrete based on the
rebound numbers, an appropriate calibration chart
shall be established based on the laboratory tests.

42. INTERPRETATION OF RESULTS
The rebound reading on the indicator scale has been
calibrated by the manufacturer of the rebound hammer for
horizontal impact.

43. FACTORS AFFECTING THE REBOUND
HAMMER TEST RESULTS :
Mix characteristics
(a) Cement type
(b) Cement content
(c) Coarse aggregate type.
Member characteristics
(a) Mass
(b) Compaction
(c) Surface type
(d) Rate of hardening and curing type