BY.

Mohd Shad Ahmad(CIB11043)

Harsh Wardhan Singh(CIB11039)

Nitish Kansari(CIB11025)

Vakeel Khan(CIB11046)

PRESENTATION ON

The Research Design and Standards Organization (RDSO) is an ISO

9001 research and development organization under the Ministry of

Railways of India, which functions as a technical adviser and consultant

to the Railway Board, the Zonal Railways, the Railway Production

Units, RITES and IRCON International in respect of design and

standardization of railway equipment and problems related to railway

construction, operation and maintenance.

Objective of the Project

Objective of the Project

To understand

Strength Assessment Of ConcreteBy using

Non Destructive Test(NDT)

Contents

What is NDT tests

Purpose of non-destructive tests (NDT)

Types of Non Destructive Tests:

NDT for strength assessment of concrete

NDT for corrosion assessment

NDT for details of reinforcement steel

NDT for locating crack and its growth

Conclusion

References

What is NDT tests?

Non-destructive testing (NDT) is a wide group of analysis techniques used in science and industry to evaluate the properties of a material, component or system without causing damage.

These methods are aimed at estimation of strength and other properties; monitoring and assessing corrosion; measuring crack size and cover; assessing grout quality; detecting defects and identifying relatively more weak areas in concrete structures.

Cost Effectiveness

Destructive testing

Huge Cost initially has to put in for taking sample and then to

test it.

Non Destructive testing(NDT)

Its very easy and simple process and a lot many tests can be

performed on concrete less than single amount require for

sampling of concrete

PURPOSE OF NON-DESTRUCTIVE TESTS:

Estimating the in-situ compressive strength

Estimating the uniformity and homogeneity

Estimating the quality in relation to standard requirement

Identifying areas of lower integrity in comparison to other parts

Detection of presence of cracks, voids and other imperfections

Monitoring changes in the structure of the concrete identification

of reinforcement profile and measurement of cover, bar diameter, etc.

Types of Non Destructive Tests:

NDT FOR STRENGTH ASSESMENT OF CONCRETE

Rebound Hammer

Windsor Probe

Core Cutter

Ultrasonic pulse velocity test

Permeability Tester

Video Borescope

NDT FOR CORROSION ASSESSMENT

Corrosion Analyzer

Resistivity Meter

NDT FOR DETAILS OF REINFORCEMENT STEEL

Profometer

NDT FOR LOCATING CRACK AND ITS GROWTH

Crack Detection Microscope

Eddy Current Meter

Infrared Thermal Imager

NDT FOR STRENGTH ASSESMENT OF CONCRETE

It is used to assess the

compressive strength of

concrete in existing structures.

When plunger of rebound

hammer is pressed against the

surface of the concrete, the

spring controlled mass rebounds

& extent of such rebound

depends on the surface

hardness which is co- related to

compressive strength of

Concrete. The compressive

strength can be read directly

from the graph provided on the

body of the hammer

1.Rebound Hammer

PRINCIPLE - It is based on the principle that the rebound of

elastic mass depends on the hardness of the concrete surface

against which the mass strikes

2.Windsor Probe

Windsor Probe is used to find

out the compressive strength

of existing concrete

structure. This equipment

gives compressive strength

of concrete by driving a

steel probe into the surface

of concrete. The lower the

depth of probe penetration,

higher the compressive

strength of concrete.

PRINCIPLE- The principle of windsor probe is like that of rebound

hammer .The penetration of the probe reflects the precise

compressive strength in area of concern. There is a graph provided

between the penetration length and the compressive strength by

which compressive strength can be known.

3.Core Cutter Machine

It is used for estimation of

physical characteristics of

masonry / concrete by

extracting core samples

from the structure. The

maximum depth of the

core which can be cut is

430 mm. The diameter of

cutters are 52mm and

78mm.

PRINCIPLE- A core is usually cut by means of rotary cutting tool

with diamond bit . Water supply is also very necessary to

lubricate the cutter. The core which is extracted from existing

structure is used for various testing's like compressive strength,

crack depth, water absorption etc.

4.Permeability Tester

This instrument is used for

determination of the air

permeability of cover

concrete. This operates

under vacuum & used on

concrete structure. It

permits a rapid & non

destructive measurement

of quality of the cover

concrete with respect to its

durability.

PRINCIPLE- Permeability tests measure the ease with which liquids, ions and gases can penetrate into the concrete. In situ tests are available for assessing the ease with which water, gas and deleterious matter such as chloride ions can penetrate into the concrete

Main UsesUsed to locate cracks, porosity, and other defects that break the surface of a material and have enough volume to trap and hold the penetrant material. Liquid penetrant testing is used to inspect large areas very efficiently and will work on most nonporous materials.

It is used for

assessment of quality

of concrete in existing

structure based on its

density. Quality of

concrete is

considered as good in

terms of its density,

homogeneity and

uniformity

5 Ultrasonic Pulse Velocity Meter

6.Video Boroscope

This instrument is used to

monitor the internal

condition of the concrete

structure.

PRINCIPLE- It’s simple

principle is to illuminate

the test specimen with

light examine the

specimen with the eye and

magnifying the defects

which can not be detected

by the unaided eye

NDT FOR CORROSION ASSESSMENT

1.Corrosion Analyzer

It is used to find

out the

likelihood of

corrosion in

Reinforcement

bars inside the

concrete

structure.

PRINCIPLE- Corrosion analyzer is based on electro chemical

process to detect corrosion in the reinforcement bar of the

structure. The instrument measures the potential and the

electrical resistance between the reinforcement and the surface

to evaluate the corrosion activity .

In field it is achieved by connecting a wire from one terminal of

a voltmeter to the reinforcement and another wire to the copper

sulphate reference electrode.

Half-cell potential (mV) relative

to copper-copper sulphate

electrode

% chance of corrosion activity

< -200 mV greater than 90% probability that

corrosion activity not taking place

200mV to – 350mV corrosion activity uncertain

> - 350mV greater than 90% probability that

Corrosion occurring

2.Resistivity Meter

This instrument is

used to measure the

electrical resistance

of concrete cover for

corrosion status of

reinforced bars.

Lower the electrical

resistance, the more

is the probability of

corrosion of metal.

PRINCIPLE- It is based on the principle that the corrosion of steel in

concrete is an electro-chemical process, which generates a flow of

current and can dissolve metals. The lower the electrical

resistance, the more readily the corrosion current flows through the

concrete and the greater is the probability of corrosion.

The limits of possible corrosion are related with Resistivity as

under:-

With p>12 kΩcm ………………………… corrosion is improbable

With p=8 kΩcm ……………………….. corrosion is possible

With p<8 kΩcm ……………………………corrosion is fairly certain

where p is resistivity

NDT FOR DETAILS OF REINFORCEMENT STEEL

1.Profometer

It is used to measure the concrete

cover and bar diameter in existing

RCC structures. It can also

identify the bar locations and

their spacing. The scanning area

permissible by the instrument is

0.5X0.5m / 1.0x1.0m / 2.0x2.0m.

PRINCIPLE : The principle is

based upon the measurement

of change of an

electromagnetic field caused

by steel embedded in the

concrete.

NDT FOR LOCATING CRACK AND ITS GROWTH

1.Crack Detection Microscopes

It is a portable type

of instrument which

detects the width of

the crack on the

surface of structure.

Used extensively to

record the extent of

crack widths on

existing piers and

abutments which are

distressed.

2.Eddy Current Meter

This instrument is

used for detecting

flaws / cracks in

steel structures. If

any crack exists

than it is displayed

on screen of the

instrument.

PRINCIPLE- It is based on the principle of electromagnetism

and particularly on inductive properties of alternating

current.

3.Infrared Thermal Imager

It is used to get

infrared and visual

images of defects

at different

locations on

concrete and steel

structure. It gives

the condition of

images captured.

PRINCIPLE : it is based on the principle that the materials with

subsurface anomalies, such as voids caused by corrosion of

reinforcing steel in a material, affect heat flow through that

material. These changes in heat flow cause localized differences

in surface temperatures. Thus, by measuring surface

temperatures under conditions of heat flow into or out of the

material, one can determine the presence and location of any

subsurface anomalies.

Black and White monitor is used:

a) black is defective concrete

b) white is sound material

Conclusion:

References

• http://en.wikipedia.org/wiki/Nondestructive_testing#Methods_and_techniques

http://www.hse.gov.uk/comah/sragtech/techmeasndt.htm#CaseStudies

• http://www.slideshare.net/mohdshadahmad/savedfiles?s_title=non-destructive-testing-ndt&user_login=mapqrs

• https://www.nde-ed.org/GeneralResources/MethodSummary/MethodSummary.htm

• http://www.engineersedge.com/inspection/inspection_pro_con.htm