NON-DESTRUCTIVE TESTING NON-DESTRUCTIVE TESTING

OF CONCRETE IN STRUCTURESOF CONCRETE IN STRUCTURES

Prepared by :Prepared by : Guided by:Guided by: NAVEEN S KADAM Prof. CM PATILNAVEEN S KADAM Prof. CM PATIL VIII Semester Dept. of Civil Engineering VIII Semester Dept. of Civil Engineering Dept. of Civil EngineeringDept. of Civil Engineering

• The usual way of testing concrete is by means The usual way of testing concrete is by means of casting cubes and then crushing them.of casting cubes and then crushing them.

• The quality of product in the field is checked The quality of product in the field is checked by non-destructive methods.by non-destructive methods.

• The main advantage is determination of The main advantage is determination of concrete properties without damage.concrete properties without damage.

INTRODUCTION :INTRODUCTION :

NEED FOR TESTING :NEED FOR TESTING :

• Monitoring long-term changes in material Monitoring long-term changes in material properties and structural performance.properties and structural performance.

• To check for the workmanship.To check for the workmanship.

• For remedial schemes and repairs.For remedial schemes and repairs.

• To check for design specification.To check for design specification.

TESTINGTESTING

NON-NON-DESTRUCTIVEDESTRUCTIVE

SEMI / PARTIAL DESTRUCTIVE TESTSEMI / PARTIAL DESTRUCTIVE TEST

DESTRUCTIVEDESTRUCTIVE

TYPES OF TYPES OF TESTING :TESTING :

NON-DESTRUCTIVE TESTING :NON-DESTRUCTIVE TESTING :

Common Methods:Common Methods:

1.1. Ultrasonic Pulse Velocity Test Ultrasonic Pulse Velocity Test

2.2. Rebound Hammer Test Rebound Hammer Test

3.3. Cover Meter Test Cover Meter Test

1. Ultrasonic Pulse Velocity Test1. Ultrasonic Pulse Velocity Test : :

• used to assess the quality and strength of in-used to assess the quality and strength of in-

situ concrete in structural members. situ concrete in structural members.

• used to check the compaction of concrete, used to check the compaction of concrete,

uniformity of concrete, determination of uniformity of concrete, determination of

cracks, presence of honeycombs, level of cracks, presence of honeycombs, level of

deterioration and also strength estimation deterioration and also strength estimation

(qualitatively).(qualitatively).Contd/……

PUNDIT (Portable Ultrasonic Non-Destructive DigitalPUNDIT (Portable Ultrasonic Non-Destructive Digital

Indicating Tester) Indicating Tester)

• consists of a pair of transducers (probes) of consists of a pair of transducers (probes) of

different frequencies, electrical pulse generator, different frequencies, electrical pulse generator,

electrical timing device and cables.electrical timing device and cables.

• It is based on the through-transmission It is based on the through-transmission

technique.technique.

Portable Ultrasonic Nondestructive Digital Portable Ultrasonic Nondestructive Digital Indicative Technique Indicative Technique ((PUNDITPUNDIT) )

Size: 180 X 110 X 160mmSize: 180 X 110 X 160mm

Weight: 3kg Weight: 3kg

Digital display with Accuracy ±0.1 microsecondsDigital display with Accuracy ±0.1 microseconds

METHODS OF TESTING :METHODS OF TESTING :

1.1. Direct transmissionDirect transmission

2.2. Indirect transmission Indirect transmission

3.3. Semi-direct transmissionSemi-direct transmission

DIRECT TRANSMISSION :DIRECT TRANSMISSION :

• Pulse velocity will be measured in concrete by Pulse velocity will be measured in concrete by placing placing transducers acrosstransducers across the member exactly the member exactly opposite to each other.opposite to each other.

• This is the most appropriate & This is the most appropriate & reliable methodreliable method

of testing to ascertain the quality / strength of of testing to ascertain the quality / strength of

concrete.concrete.

DIRECT TRANSMISSION OF

PULSE ACROSS R.C BEAM

DIRECT TRANSMISSION OF

PULSE IN R.C COLUMN

INDIRECT TRANSMISSION :INDIRECT TRANSMISSION :

• Pulse velocity will be measured in concrete by Pulse velocity will be measured in concrete by placing transducers on the placing transducers on the same planesame plane of members. of members.

• This is the This is the least reliableleast reliable method of testing to method of testing to ascertain the quality / strength of concrete. This ascertain the quality / strength of concrete. This method will be method will be adoptedadopted only when there is no other only when there is no other option.option.

INDIRECT TRANSMISSION OF PULSE IN R.C.DECK

SEMI-DIRECT TRANSMISSION :SEMI-DIRECT TRANSMISSION :

• Pulse velocity will be measured in concrete by Pulse velocity will be measured in concrete by placing transducers in planes perpendicular to each placing transducers in planes perpendicular to each other.other.

• This is a This is a moderately reliablemoderately reliable method of testing to method of testing to ascertain the quality / strength of concrete.ascertain the quality / strength of concrete.

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

Method of calculation of pulse velocity :

Velocity = Velocity = (Distance travelled / Path length)(Distance travelled / Path length) Time takenTime taken

Pulse Velocity in concrete will be represented Pulse Velocity in concrete will be represented in in Km/secKm/sec..

Appropriate Appropriate correction factorscorrection factors to be applied to be applied depending on site condition & factors depending on site condition & factors influencing velocity of pulse.influencing velocity of pulse.

Pulse Velocity Pulse Velocity (kM/sec)(kM/sec)

Concrete Quality Concrete Quality Grading (as per IS:13311 Grading (as per IS:13311

(Part-1)-1992)(Part-1)-1992)

Below 3.0Below 3.0 DoubtfulDoubtful

3.1 to 3.53.1 to 3.5 MediumMedium

3.5 to 4.53.5 to 4.5 GoodGood

Above 4.5Above 4.5 ExcellentExcellent

QUALITY GRADING CHART :QUALITY GRADING CHART :

FACTORS INFLUENCING THE VELOCITY FACTORS INFLUENCING THE VELOCITY OF PULSE IN CONCRETE :OF PULSE IN CONCRETE :

• Type & content of cementType & content of cement

• Influence of reinforcementInfluence of reinforcement

• Use of admixturesUse of admixtures

• Type & size of aggregatesType & size of aggregates

• Homogeneity & density of concreteHomogeneity & density of concrete

• Age of concreteAge of concrete

• Presence of voids / cavities in concretePresence of voids / cavities in concrete

• Cracks in concreteCracks in concrete

• Curing of concrete, etc.,Curing of concrete, etc.,

• Measurement of concrete uniformityMeasurement of concrete uniformity• Detection of cracking and honeycombingDetection of cracking and honeycombing• Strength estimationStrength estimation• Assessment of concrete deteriorationAssessment of concrete deterioration• Measurement of layer thicknessMeasurement of layer thickness• Measurement of elastic modulusMeasurement of elastic modulus• Strength development monitoring.Strength development monitoring.

APPLICATIONS :APPLICATIONS :

2. REBOUND HAMMER TEST :2. REBOUND HAMMER TEST :

• It is a quick method for assessing the quality of It is a quick method for assessing the quality of concrete based on surface hardness indicated by concrete based on surface hardness indicated by the Rebound number. the Rebound number.

• An higher rebound value indicates the higher An higher rebound value indicates the higher strength / surface hardness of concrete.strength / surface hardness of concrete.

• This equipment works based on the spring This equipment works based on the spring controlled hammer slides on a plunger within a controlled hammer slides on a plunger within a tubular housing.tubular housing.

Figure: Rebound HammerFigure: Rebound Hammer.

Weight < 2KgWeight < 2Kg

Impact Energy = 2.2NmImpact Energy = 2.2Nm

Suitability 20 – 60 MPaSuitability 20 – 60 MPa

Figure: Testing by Rebound Hammer

METHODS OF TESTING :METHODS OF TESTING :

Depending on the position of the rebound hammerDepending on the position of the rebound hammer

1.1. HorizontalHorizontal

2.2. Vertically upwardsVertically upwards

3.3. Vertically downwardsVertically downwards

4.4. Inclined vertical upwardsInclined vertical upwards

5.5. Inclined vertical downwardsInclined vertical downwards

POSITION OF REBOUND HAMMER - VERTICAL UPWARDS

POSITION OF REBOUND HAMMER - POSITION OF REBOUND HAMMER - VERTICAL DOWNWARDSVERTICAL DOWNWARDS

METHOD OF CALCULATION : METHOD OF CALCULATION :

•Average rebound number will be calculated Average rebound number will be calculated after exclusion of freak values and applying after exclusion of freak values and applying necessary necessary correction factorcorrection factor for position of for position of Rebound Hammer.Rebound Hammer.

•To evaluate the strength of concrete based on To evaluate the strength of concrete based on the rebound numbers, an appropriate the rebound numbers, an appropriate calibration calibration chartchart shall be established based on the laboratory shall be established based on the laboratory tests.tests.

FACTORS AFFECTING THE REBOUND FACTORS AFFECTING THE REBOUND HAMMER TEST HAMMER TEST RESULTS :RESULTS :

Mix characteristicsMix characteristics

(a) Cement type(a) Cement type

(b) Cement content(b) Cement content

(c) Coarse aggregate type.(c) Coarse aggregate type.

Member characteristicsMember characteristics

(a) Mass(a) Mass

(b) Compaction(b) Compaction

(c) Surface type(c) Surface type

(d) Rate of hardening and curing type(d) Rate of hardening and curing type

3. COVER METER TEST :3. COVER METER TEST :

• Used for locating, mapping and thickness Used for locating, mapping and thickness gauging of cover provided for embedded rebars gauging of cover provided for embedded rebars in concrete.in concrete.

• Equipment used Equipment used Profometer Profometer works on works on

electromagnetic principles. The equipment electromagnetic principles. The equipment

consists of display unit coupled with probes of consists of display unit coupled with probes of

different types. different types.

ESTIMATION OF COVER AND MAPPING OF REBARS IN ABUTMENT

ESTIMATION OF COVER AND MAPPING OF REBARS IN BEAM

LIMITATIONS OF THE EQUIPMENT :LIMITATIONS OF THE EQUIPMENT :

• Only peripheral rebars can be detectedOnly peripheral rebars can be detected

• Second layer (if any) of rebar's cannot be detectedSecond layer (if any) of rebar's cannot be detected

• The accuracy of the diameter of rebar will vary The accuracy of the diameter of rebar will vary generally in the range of 10 to 20%generally in the range of 10 to 20%

• The actual numbers and position of rebars cannot The actual numbers and position of rebars cannot be located if the rebars are closely spaced in one be located if the rebars are closely spaced in one location location

CONCLUSIONS :CONCLUSIONS :

1.1. There are number of tests such as Non-There are number of tests such as Non-Destructive, Semi/Partial Destructive and Destructive, Semi/Partial Destructive and Destructive tests that in practice to evaluate Destructive tests that in practice to evaluate structural members. structural members.

2.2. Depending on data required, site conditions, Depending on data required, site conditions, structural member conditions, etc., any one of structural member conditions, etc., any one of them or combination of the above can be used them or combination of the above can be used to ascertain the status of memberto ascertain the status of member

contd..contd..

33. . All these test procedures will give very good All these test procedures will give very good information about the condition of the structural information about the condition of the structural members. members.

4. It is very important to achieve most accurate and 4. It is very important to achieve most accurate and reliable results, for which the person who reliable results, for which the person who operates the equipments should be technically operates the equipments should be technically sound and shall have good experience.sound and shall have good experience.

THANK YOUTHANK YOU