This document discusses non-destructive testing (NDT) methods for assessing existing structures. It describes several NDT techniques including visual inspection, liquid penetrant testing, magnetic particle inspection, ultrasonic testing, radiography, and rebound hammer testing. Each method is able to detect different types of defects without damaging the material. NDT provides benefits like enabling further usage of the tested object and maintaining statistical data for future reference. Common applications of NDT include flaw detection, leak detection, and evaluating dimensions or internal structure.

1. G.V.Manoj Kumar
U.Maadaswamy
RMK ENGG. COLLEGE

2. OBJECTIVE
 Assessment of existing structure for rehabilitation
planning
 Detection of cracks, voids and other imperfections in the
material
 Monitoring changes in the concrete with the passage of
time

3. Non-destructive testing
 Is a form of testing to be carried out on various
construction members and materials without causing any
permanent damage to them.
 Does not permanently alter the article being tested

4. Difference between:
Destructive testing Non-destructive testing
 Carried out until specimen’s
failure
 will render the part unusable
for its intended purpose
 Does not destroys the test
specimen
 after testing, allow the part to
be used for its intended purpose

5. NDT-methods
 Visual inspection(VI)
 Liquid (dye) penetrant test
 Magnetic particle inspection(MI)
 Ultrasonic testing
 Radiography(X-ray)
 Schmidt rebound hammer

6. Visual inspection
 Oldest non-destructive testing method
 can successfully detect the unacceptable surface
discontinuities
 cheap and reliable testing method

7. Liquid (Dye) penetrant test
 To detect surface-breaking discontinuities in all non-
porous materials (metals, plastics, or ceramics).
 It is based upon the principles of capillary action
where liquid penetrates into a cavity.
 Fast, economical and widely used method

9. Magnetic particle inspection
 Used to detect defects on the surface or near to the
surface.
 Generate magnetic flux in article to be examined.
 The particles are often colored and usually coated with
fluorescent dyes that are made visible with a hand-held
ultraviolet (UV) light

11. Magnetic flux concentration

12. Ultrasonic testing
 Detect both internal and
surface defect in sounding
conducting material.
 Any change in acoustic
impedance produces ultrasonic
reflection or echo

13. Ultrasonic testing is done for the concrete

15. Radiography (X-ray)
 Radiography uses X-rays and gamma-rays to produce a
radiograph of a specimen
 shows any changes in thickness, defects (internal and
external)
 to obtain permanent image of surface and sub-surface
discontinuities

16. Radiography test on a concrete beam

17. Rebound hammer
 Measures the rebound of a spring-loaded mass
 hammer will hit the concrete and rebound is dependent
on the hardness of the concrete
 The Schmidt hammer is an arbitrary scale ranging from 10
to 100.

18. Procedure of the test

19. Suitability of testing
 Ultrasonic testing-sub surface, interstitial
 Magnetic particle inspection-surface, sub surface
discontinues
 Dye penetrant test-surface-breaking defects in all non-
porous materials
 Radiographic testing-surface, sub-surface defects

20. NDT- Benefits
 Sample -available afterwards for repeat or additional
tests.
 Enables further use of work piece.
 Provides cost benefits.
 Enables comparison to standard and established results.
 Enables maintenance of statistical data for future
interpretation.

21. Uses of NDT
 Flaw Detection and Evaluation
 Leak Detection
 Location Determination
 Dimensional Measurements
 Structure and Microstructure Characterization
 Estimation of Mechanical and Physical Properties

22. Conclusion
 Non-destructive testing is not only economical but
gives very unique results
 Involves very less time when compared to universal
testing machine