NON DESTRUCTIVE TESTING OF CONCRETE STRUCTURES PPT
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Various techniques required for testing of materialsFull description
Pengetahuan tentang NDTFull description
the reports describes various methods non destructive techniques for detecting hidden corrosionFull description
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Non Destructive Testing
This work presents a study on the comparison between Destructive Compressive test and Non destructive testing techniques Schmidt Rebound Hammer . Tests moisture content, Sieve analysis, particle density for aggregate and cement paste, bulk density, s
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Design of Concrete Structures nilsonDescripción completa
Non - Destructive Test for steelwork UT- Ultrasonic Test RT- Radiographic Test MPI- Magnetic Particle TestFull description
Gives brief summaries of a wide range of tests for determining the quality of concrete in situ.
Gives brief summaries of a wide range of tests for determining the quality of concrete in situ.
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Durability Design of Concrete Structures
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Descripción: Durability Design of Concrete Structures
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Brazing Methods for non-destructive & destructive testing
NON DESTRUCTIVE TESTING OF CONCRETE STRUCTURES
PRESENTED BY CHANDAN ASHISH (1 (118/08) 18/08) FARAH NAWAZ (138/08)
INTRODUCTION Nondestructive testing (NDT) is a wide group of analysis techniques used to evaluate the properties of a material, component or system without causing damage.
TYPES OF TESTING OF CONCRETE STRUCTURES
DESTRUCTIVE TESTING
NONDESTRUCTIVE TESTING
DESTRUCTIVE TESTING
Stress Testing
Crash Testing
Hardness Testing
Destructive testing of a 6-storey concrete building using a shake table
TYPICAL DEFECTS IN CONCRETE STRUCTURES
Cracks due to concrete settling
Sketch of exposed aggregate
Cracks due to differential settlement
Rusting of reinforcing bars
Effect of atmospheric conditions
Cracks due to bending and shear stresses
SCHMIDT REBOUND HAMMER TEST Principle : It works on the principle that the rebound of an elastic mass depends on the hardness of the surface against which the mass impinges.
Schmidt Rebound Hammer
A cutaway schematic view of the Schmidt rebound hammer
Relationship between Compressive strength of concrete and Rebound Number
CARBONATION DEPTH MEASUREMENT TEST Carbonation of concrete occurs when the carbon dioxide, in the atmosphere in the presence of moisture, reacts with hydrated cement minerals to produce carbonates, e.g. calcium carbonate
t = (d/k)2 Where,
t = carbonation time d = concrete cover k = permeability Concrete Grade 15 20 25 30 35 40
Permeability 17 10 6 5 4 3.5
Estimation of depth of Carbonation 7.2 2 y= C R2(4.6x – 1.76)2
Where, y = Age of building in years x = Water-Cement Ratio C = Carbonation depth R = Constant (R= αβ)
ULTRASONIC TESTING – Pulse Velocity Test A pulse of longitudinal vibrations is produced by a transducer, which is held in contact with one surface of the concrete under test. Electronic timing circuits enable the transit time T of the pulse to be measured.
Longitudinal pulse velocity (in km/s or m/s) is given by:
v = L/T where , v = Longitudinal pulse velocity L = Path Length T = Time taken by the pulse to traverse that length.
Transducer Arrangement
Direct transmission
Semi-direct transmission
Key : Transmitter (T) Receiver (R)
Indirect or surface transmission
Pulse velocity determination by indirect (surface) transmission.
(a) Results for concrete with the top 50 mm of inferior quality (b) Results for homogeneous concrete.
RADIOGRAPHIC TESTING
The intensity of a beam of X rays or gamma rays suffers a loss of intensity while passing through a material. The amount of radiation lost depends on the quality of radiation, the density of the material and the thickness traversed The relationship between the intensity of photons incident and transmitted is:
Schmidt Hammer , GPR Test being conducted on a bridge A
well-established and accepted application of GPR is the accurate condition assessment of bridge decks as well as other reinforced concrete structures. Infrared imaging technologies to find defects in the concrete parts of bridges. Ultrasonic testing allows also the visualization of perpendicularly arranged reinforcement bars.
CONCLUSION
A large range of NDT techniques are deployed for a wide variety of application in Civil Engineering. NDT techniques can be used for evaluation and inspection of both new and existing structures. Apart from methods discussed here, they are still a constant field of research and development due to their significance.
REFERENCES
INTERNATIONAL ATOMIC ENERGY AGENCY ,VIENNA,2002 Guidebook on Non Destructive testing of Concrete Structures .
