Table of Contents

1.0 Individual background...................................................................................................... 1

1.1 (Tan Wan Ying, 16WVD02869) ..................................................................................... 1
1.2 Tan Wan Xuan (16WVD03439) ..................................................................................... 3
1.3 Tan Wen Lu (16WVD07280) .......................................................................................... 5
1.4 Tee Kai Yuan (16WVD04775) ....................................................................................... 7
1.5 Tee Ser Mien (16WVD05122) ........................................................................................ 9
2.0 Title ................................................................................................................................... 10
3.0 Aim.................................................................................................................................... 10
4.0 Objectives ......................................................................................................................... 10
5.0 Equipment ........................................................................................................................ 10
6.0 Material ............................................................................................................................ 10
7.0 Procedure ......................................................................................................................... 10
Results and Calculation ........................................................................................................ 16
8.0 Discussion ......................................................................................................................... 19
9.0 Conclusion ........................................................................................................................ 20
10.0 References ...................................................................................................................... 21
1.0 Individual background
1.1 (Tan Wan Ying, 16WVD02869)

Non-destructive testing of concrete using ultrasound are frequently used to

estimate the quality of concrete. These methods are normally based on the measurement
of the propagation of velocity that closely related to mechanical properties and it is
more directly to the modulus of elasticity. The principle of the test is that the velocity
of sound in a solid material, V, is a function of the square root of the ratio of its modulus
of elasticity, E, to its density. The method started with determine the time required for
a pulse of vibrations at an ultrasonic frequency to travel through concrete. When the
velocity is determined, we can attain an idea about the quality, uniformity, condition,
and strength of the concrete tested. (Limbachiya and Kew, 2008)
The Ultra Pulse Velocity method, also known as the transit time method, uses a
detector to measure the time of flight taken by an ultrasonic pulse to pass through a
solid material. (Limbachiya and Kew, 2008) Ultra-sonic Pulse Velocity (UPV)
equipment consists of two transducers, a transmitter and a receiver. An electronic
trigger or timer device measures the transit time of an ultrasonic pulse through material
between the transducers. UPV is calculated from the transit time and measured it path
length. UPV is a function of the modulus and density of the material, it provides
comparative data for the assessment of concrete uniformity. The transit time may be
affected by the cracks, inclusions, honeycombing, and voids which cause the diverting
of pulse and reducing of velocity. It can also measure crack depth and direction in some
circumstances. (Chaker, 1992)

Figure 1 UPV equipment (Geotechnics, 2017)

There are three alternative arrangements commonly used for the transducers when
testing the concrete. The three transducer arrangement are direct, semi-direct and
indirect or surface. Whenever possible, the direct transmission arrangement should be
used as this ensures the maximum sensitivity and provide a well-defined path length.
The path length is the distance between the centres of each transducer. The semi-direct
arrangement is less sensitive than the direct, but more sensitive than the indirect
arrangement. However, sometimes required to examine the concrete by using diagonal
paths and semi-direct arrangements are suitable for these. The indirect arrangement is
the least satisfactory because it is relatively insensitive and the length of the path is less
well defined. The indirect arrangement gives pulse velocity measurements which are
1
usually influenced by the concrete layer near the surface and this layer may not
represent the concrete in deeper layers. However, the indirect method also particularly
useful for determining crack depth, surface quality or the case when only one surface
is accessible. In general, it will be found that the pulse velocity determined by the
indirect method of testing will be lower than that using direct method. (Choo and
Newman, 2003)

Figure 2 Three transducer arrangement (Pinterest, 2017)

References
1. Chaker, V. (1992). Corrosion forms and control for infrastructure. Philadelphia, Pa:
American Society for Testing Materials, p.366.

2. Choo, B. and Newman, J. (2003). Advanced Concrete Technology 4: Testing and

Quality. Oxford: Butterworth-Heinemann, pp.6/21-6/22.
3. Geotechnics. (2017). Pundit Lab Plus Ultrasonic Pulse Velocity Tester. [Online]
Available at: https://www.geotechnics.co.nz/buy/concrete-8/pundit-lab-plus-
ultrasonic-pulse-velocity-tester/ [Accessed 10 Nov. 2017].
4. Limbachiya, M. and Kew, H. (2008). Excellence in concrete construction through
innovation. Leiden: CRC Press/Balkema, p.49.
5. Pinterest. (2017). Ultrasonic Pulse Velocity Test. [online] Available at:
https://www.pinterest.com/pin/410038741053610215/ [Accessed 10 Nov. 2017].

2
1.2 Tan Wan Xuan (16WVD03439)

Ultrasonic testing is a versatile non-destructive testing method which is applicable

to most materials, metallic or non-metallic. By this method, surface and internal
discontinuities such as laps, seams, voids, cracks, blow holes, inclusions, lack of bond
and others can be accurately evaluated from one side. Ultrasonic testing utilizes high
frequency acoustic waves generated by piezoelectric transducers. Frequencies from 1
to 10 Mega Hertz (MHz) are typically used, although lower or higher ranges are
sometimes required for certain applications. The resultant acoustic wavelengths in the
test material (depend on the ultrasonic wave velocity) are of the order of one to ten
millimeters. A highly directional sound beam is transmitted to the test piece through a
suitable couplant, usually grease or oil like material. While various types of
instrumentation and display modes are feasible, the most widely employed is the pulse-
echo technique, with A-scan mode (Baldev Raj, 2002).

Figure 1.1 Ultrasonic Pulse Velocity (UPV) (Baldev Raj, 2002)

When an ultrasonic pulse traveling through concrete meets a concrete-air interface,

there is a negligible transmission of energy across this interface so that any air-filled
crack or void lying directly between the transducers will obstruct the direct beam of
ultrasound when the void has a projected area larger than the area of the transducer
faces. The first pulse to arrive at the receiving transducer will have been diffracted
around the periphery of the defect and the transit time will be longer than in similar
concrete with no defect. The arrangement for direct method is where it requires access
to two surfaces. The transmitting and receiving transducers are placed on opposite
surfaces of the concrete slab. This will give maximum sensitivity and provide a well-
defined path length (M.Meganathan, 2003).

Performing UPV testing requires access to two surfaces, unless indirect (surface
transmission) testing is to be done. Though indirect arrangement is least satisfactory
upon sensitivity and defined path length, but it is more commonly used since direct
method is not possible to use at most of the time (M.Meganathan, 2003).

3
 UPV method can be used for estimating the depth of surface cracks. To do so, each
transducers should be place on one side of the crack, for a given distance. Then, the
distance between transducers is changed in the same trajectory. The UPV measurement
will be repeated for different spacing of transducers (Damon S.W., 2015).

Reference
Baldev Raj, 2002, Practical Non-destructive Testing, Narosa Publishing House,
New Delhi.
M.Meganathan, 2003, A Comparison between Direct and Indirect Method of
Ultrasonic Pulse Velocity in Detecting Concrete Defects,
<http://www.ndt.net.com>, viewed at 10 November 2017.
Damon S.W., 2015, 3 Methods for Crack Depth Measurement in Concrete,
<http://www.fprimec.com/3-methods-crack-depth-measurement-in-concrete/>,
viewed at 10 November 2017.

4
1.3 Tan Wen Lu (16WVD07280)

In the construction industry, it is important to ensure that structures are built

properly using the highest-quality materials and construction methods. Hence, certain
tests must be conducted to ensure the quality of certain materials. The ultrasonic pulse
velocity test is one of the most essential tests designed to determine the quality of
natural rock and concrete. This testing method is preferred because it is non-destructive
and it is conducted on site, saving builders a lot of time and money. In an ultrasonic
pulse velocity test, the quality and strength of rock or concrete is determined by
measuring the velocity of the ultrasonic pulse, which passes through the natural rock
formation or concrete structure.

The test is conducted using specialized equipment that generates a pulse of

ultrasonic wave and measuring the time it takes for that pulse to go through the concrete.
A high velocity indicates that the material is continuous and high-quality and a slower
velocity may indicate voids and cracks in the concrete. Ultrasonic pulse velocity testing
equipment is versatile and can be used to determine a materials homogeneity, quality
in relation to certain requirements, and the materials modulus or strength. Testing lets
you find internal defects and imperfections and determine the changes occurring in
concrete as a result of time, hydration, and damage from chemical attacks, frost, or fire.

In this paper, water content and temperature effect on the ultrasonic pulse
velocity (UPV) of concrete was investigated. A series of tests were performed to
examine the relationship between water content and UPV of concrete with different
aggregate mixture proportions. Cube test specimens were made of concrete with
water-cement ratio of 0.5. The concrete specimens were immersed in water for 90
days to saturate them. To measure the effect of different water contents on UPV, the
test specimens were dried gradually to change the amount of water between
measurements. This process was repeated until the concrete pieces were completely
dried and weight no longer changed.

The water content could be changed from about 6 to 0%. Following, another
test procedure was conducted to research the relationship between temperature and
UPV. To measure the influence of various temperatures on UPV, completely dried
concrete specimens were firstly cooled to 18C and gradually heated to +180C. In
these two different procedures, the UPV values corresponding water content and
temperature in the relevant ranges were periodically measured. The test results
indicate that the increase in both water content and temperature increases almost
linearly UPV of concrete. Based on correlation derived from the test data, irrespective
of concrete properties a further increase in both water content of 1% and temperature
of 10C increases UPV of average 160 and 34 m/s, respectively. As overall
assessment, this study demonstrates that the UPV is a function of both water content
and temperature, and the changing of these two parameters has an important influence
on ultrasonic pulse velocity of concrete.

5
References:
1. http://pcteau.blogspot.com/2017/03/importance-of-ultrasonic-pulse-
velocity.html
2. https://link.springer.com/article/10.1134%2FS1061830917020024

6
1.4 Tee Kai Yuan (16WVD04775)

An ultrasonic pulse velocity test is an in-situ, non-destructive test to check the

quality of concrete and natural rocks. In this test, the strength and quality of concrete
or rock is assessed by measuring the velocity of an ultrasonic pulse passing through a
concrete structure or natural rock formation. This test is conducted by passing a pulse
of ultrasonic wave through concrete to be tested and measuring the time taken by pulse
to get through the structure. Higher velocities indicate good quality and continuity of
the material, while slower velocities may indicate concrete with many cracks or voids.
(Sam, 2016)
Ultrasonic waves are very similar to light waves in that they can be reflected,
refracted, and focused. Reflection and refraction occurs when sound waves interact with
interfaces of differing acoustic properties. Ultrasonic reflections from the presence of
discontinuities or geometric features enables detection and location. (Sam, 2016)
Ultrasonic Pulse Velocity (UPV) testing of concrete is based on the pulse
velocity method to provide information on the uniformity of concrete, cavities, cracks
and defects. Presence of voids, honeycombing or other discontinuities. The pulse
velocity in a material depends on its density and its elastic properties which in turn are
related to the quality and the compressive strength of the concrete. This test method is
applicable to assess the uniformity and relative quality of concrete, to indicate the
presence of voids and cracks, and to evaluate the effectiveness of crack repairs. It is
also applicable to indicate changes in the properties of concrete, and in the survey of
structures, to estimate the severity of deterioration or cracking. (Quavo, 2015)

Figure 3 PUNDIT (Jack, 2015)

The UPV equipment such as PUNDIT includes a transducer, a receiver and an

indicator for showing the time of travel from the transducer to the receiver. Ultrasonic
pulse uses fast potential changes to create vibration that leads to its basic frequency.
The transducer is firmly attached to concrete surface to vibrate the concrete. The pulses
go through the concrete and reach the receiver. (Jack, 2015)
The pulse velocity can be determined from the following equation. (Jack, 2015)
V=L/T
Where V = pulse velocity (km/s), L = path length (cm), T = transit time (s).

7
References
Jack, 2015. Oneengineering. [Online]
Available at: http://www.olsonengineering.com/methods/structural-pavement-tunnel-
methods/ultrasonic-pulse-velocity.html
[Accessed 13 november 2017].

Quavo, 2015. Pcte. [Online]

Available at: http://www.pcte.com.au/pundit-lab-ultrasonic-tester
[Accessed 13 November 2017].

Sam, 2016. Control group. [Online]

Available at: http://www.controls-group.com/eng/concrete-testing-equipment/ultrasonic-
pulse-velocity-tester.php
[Accessed 13 November 2017].

8
1.5 Tee Ser Mien (16WVD05122)

Cracks can be described as tiny as hairline, or cracks with a few millimetres

opening on the RC surfaces depending on the opening of the cracks. But this
procedure does not provide enough information about the depth of these cracks.
Evaluation of existing surface cracks is normally done during the visual inspection of
structures. Crack opening on the surface of concrete is normally measured using a
crack gauge.

There are three different methods for measurement of the depth of crack.
Firstly are Visual Examination of Concrete Cores, Impact Echo, and Ultrasonic Pulse
Velocity. In this experiment, we are using the method of Ultrasonic Pulse Velocity.

Ultrasonic Pulse Velocity (UPV) is an effective non-destructive testing (NDT)

method for quality control of concrete materials, and detecting damages in structural
components. The UPV methods have traditionally been used for the quality control of
materials, mostly homogeneous materials such as metals and welded connections.
With the recent advancement in transducer technology, the test has been widely
accepted in testing concrete materials. Ultrasonic testing of concrete is an effective
way for quality assessment and uniformity, and crack depth estimation
(SOLUTIONS, 2017).

UPV method can be used for estimating the depth of surface cracks. To do so,
each transducer should be place on one side of the crack, for a given distance. Then,
the distance between transducers is changed in the same trajectory. The UPV
measurement will be repeated for different spacing of transducers (SOLUTIONS,
2017).
Pulse velocity is related with crushing strength of concrete. The pulse velocity
in concrete may be influenced by the path length, lateral dimension of the specimen
tested, presence of reinforcement steel and moisture content of the concrete
(GOPAL,2017)

References

1. The Constructor. (2017). what is Ultrasonic Testing of Concrete for

Compressive Strength? [online] Available at:
https://theconstructor.org/concrete/ultrasonic-test-on-concrete/2847/
[Accessed 13 Nov. 2017].
2. FPrimeC Solutions. (2017). 3 Methods for Crack Depth Measurement in
Concrete | FPrimeC Solutions. [online] Available at:
http://www.fprimec.com/3-methods-crack-depth-measurement-in-concrete/
[Accessed 13 Nov. 2017].

9
2.0 Title: Measurement of Pulse Velocity, Surface Velocity and Crack Depth.

3.0 Aim
Using the Pundit Lab ultrasonic instrument to measure Pulse Velocity, Surface
Velocity and perpendicular crack depth.

4.0 Objectives:
A) To determine the Pulse Velocity of an ultrasonic instrument in a RC structure.
B) To measure the surface velocity of an ultrasonic instrument through a RC
structure
C) To measure the perpendicular crack depth in a RC structure.

5.0 Equipment:
A) Ultra-Pulse Velocity (UPV) Equipment
B) RC structure/ RC surface

6.0 Material:
A) Meter ruler
B) Chalk
C) Tissue
D) Gel

7.0 Procedure

1. Basic Measurement - To measure the pulse velocity through a column with direct
arrangement of transducers.
a) Measured the path length of the column identified for the test.

Figure 4 Measure the path length

10
 b) Followed the steps given below :

Figure 5 the procedure to operate the Pundit Lab

Figure 6 Measure the pulse velocity through a column

c) Recorded the readings taken in the table below:

Readings Taken
1 2 3
Path Length (m)
Pulse velocity
(m/s)
Table 1

11
2. Basic Measurement - To measure the surface velocity through a concrete surface with
indirect arrangement of transducers.
a) Measured the distances b and 2b on the concrete surface identified for the test.

Figure 7 Clean the surface and measure the distance

b) Followed the steps given below :

Figure 8 The procedure to operate the Pundit Lab

Figure 9 The procedure to operate the Pundit Lab

12
 Figure 10 Measure the surface velocity

c) Recorded the readings taken in the table below :

Readings Taken
1 2 3
Surface velocity
Table 2

13
3. Compound Measurement - To measure the perpendicular crack depth of a concrete structure.
a) Drew a line perpendicular to the crack identified for the test.

Figure 11 Draw a line perpendicular to the crack

b) Followed the steps given below :

Figure 12 The procedure to operate the Pundit Lab

Figure 13 The procedure to operate the Pundit Lab

14
 Figure 14 Measure the perpendicular crack depth

c) Recorded the readings taken into he table below :

Readings Taken
1 2 3
Perpendicular Crack
depth
Table 3

15
Results and Calculation

1) Report the results that have been taken on the measurements of pulse velocity, surface
velocity and perpendicular crack depth.

1. Basic Measurement
Readings Taken 1 2 3
Path Length (m) 0.252 0.252 0.252
Pulse Velocity(m/s) 3539 3595 3700
T1 (s) 71.2 70.1 68.1

2. Basic measurement
Readings Taken 1 2 3
Surface 1037 2500 6494
Velocity(m/s)
T1 (s) 2.9 24.9 24.9
T2 (s) 51.1 44.9 32.6

3. Compound Measurement
Readings Taken 1 2 3
Perpendicular 0.035 0.029 -
Crack Depth (m)
T1 (s) 28.9 22.9 22.9
T2 (s) 43.6 36.4 55.9
Velocity (m/s) - - 1471

16
2) An estimate of crack depths may be obtained by use of indirect surface readings as
shown in Figure 2. In this case, where the transducers are equidistant from a known crack, if
the pulse velocity through a sound concrete is V km/s, then:

Path length without crack = 2x

= 2(0.060)
= 0.120m

(0.035 0.029)
Path length around crack = 2 x 2 h 2 h
2

= 2 0.030 2 0.032 2 = 0.032m

= 0.088m

2x
Surface travel time without crack = = TS
V
2(0.060)
= = TS
1.471
= 0.082s = TS

2 x 2 h2 (1037 2500 6494)

Travel time around crack = = Tc V
V 3

2 0.0302 0.0322
= = Tc = 3343.667m/s
3.344
= 0.026s = Tc = 3.344km/s

and it can be shown that

Tc 2
crack depth, h = x 2 1
Ts

0.0262
= 0.030 2
1
0.082

= 0.028m

17
An accuracy of 15% can normally be expected,
(0.035 0.029) (0.035 0.029)
Average h = 85 % OR average h = 115 %
2 2
= 0.027m = 0.037m

So, crack depth, h = 0.028m is in the range between 0.027m to 0.037m, it is acceptable.

18
8.0 Discussion
1) Elaborate on any THREE (3) application of UPV test result.
The application of UPV test is qualitative assessment of strength of concrete. Its
gradation in different locations of structural members and plotting the same. Then, UPV test
can be use as any discontinuity in cross section such as cracks and cover concrete delamination.
Lastly, UPV test can detect the depth of surface cracks so that we can give different solution
to solve the problem. (James, 2016)

2) Briefly explain on THREE (3) advantages of UPV tests.

Ultrasonic pulse velocity testing is a revolutionized non-destructive testing which can
be applied on various structures. Concrete testing equipment that uses ultrasonic pulses
provides faster and more accurate result. Moreover, the test can be conducted without causing
any destruction or damages to the concrete element. Using an ultrasonic pulse velocity test may
help save money and time at the same time because it eliminates the need to test, break, and
throw away hundreds of cylinders and cubes. (Jenifer, 2015)
Ultrasonic pulses also provide a reliable measure of the changes in concrete. Chemical
attacks, frost, fire, and cement hydration are some of the reasons why concrete may change or
become defective. An ultrasonic pulse velocity test may help determine the modulus or strength
of the material, and make sure that the concrete is still able to conform to specified regulations
and standard requirements. (Jenifer, 2015)
In an ultrasonic pulse velocity test, the material's pulse velocity is determined by the
material's density and elastic properties, both of which are related to the material's strength and
quality. High-quality ultrasonic pulse equipment enables a reliable and more accurate way to
determine the internal properties of materials. Hence, it is useful for determining a material's
homogeneity and for detecting the presence of cracks, defects, voids, and other imperfections
within the structure. (James, 2016)

3) Briefly explain on any THREE (3) of the limitations of UPV tests.

Ultrasonic pulse velocity method will some limitations such as manual operation of
the instrument requires careful attention by experienced technicians. If not, it may get error
data or cannot get the data. Next, Ultrasonic pulse velocity method need to have smooth surface.
If the surface is irregular it is difficult to estimate accurately the pulse velocity. Lastly, the test
objects must be water resistant. If not, it will hard to get data or the data will have error. (David,
2016)

19
9.0 Conclusion

A pulse velocity test is an in-situ, non-destructive test to check the quality

of concrete and natural rocks. In this test, the strength and quality of concrete or rock is
assessed by measuring the velocity of a pulse passing through a concrete structure or natural
rock formation. This test is conducted by passing a pulse of ultrasonic wave through concrete
to be tested and measuring the time taken by pulse to get through the structure. Higher
velocities indicate good quality and continuity of the material, while slower velocities may
indicate concrete with many cracks or voids. (Kate, 2016)
Ultrasonic testing equipment includes a pulse generation circuit, consisting of
electronic circuit for generating pulses and a transducer for transforming electronic pulse into
mechanical pulse having an oscillation frequency in range of 40 kHz to 50 kHz, and a pulse
reception circuit that receives the signal. The transducer, clock, oscillation circuit, and power
source are assembled for use. After calibration to a standard sample of material with known
properties, the transducers are placed on opposite sides of the material. Pulse velocity can be
measured by a simple formula: pulse velocity is equal to width of structure divide by time taken
for pulse to go through. (Kate, 2016)
The ability to reliably measure the depth of small surface-breaking cracks is very
desirable in a range of high value industries including aerospace, petrochemical, power
generation and nuclear. Knowledge of the presence of a crack whose depth is unknown
normally results in automatic rejection of parts, both at manufacture and in service. This is an
expensive practice and can cause significant disruption. If the depth of a crack is known, this
information can be used in fracture mechanics calculations to allow a better estimate of the risk
which the crack poses to the system. It is particularly useful to be able to size small cracks
accurately since these are the ones that will pose the least risk and are therefore most likely to
be allowed. (samueal, 2016)

20
10.0 References
David, 2016. Theconstructor. [Online]
Available at: https://theconstructor.org/concrete/ultrasonic-test-on-concrete/2847/
[Accessed 13 November 2017].

Jack, 2015. Oneengineering. [Online]

Available at: http://www.olsonengineering.com/methods/structural-pavement-tunnel-
methods/ultrasonic-pulse-velocity.html
[Accessed 13 november 2017].

James, 2016. engineeringcivil. [Online]

Available at: http://www.engineeringcivil.com/ultrasonic-pulse-velocity-method.html
[Accessed 13 November 2017].

Jenifer, 2015. NDT. [Online]

Available at: http://www.ndt.net/article/ndtnet/2015/Lorenzi1.pdf
[Accessed 13 November 2017].

Kate, 2016. slideshare. [Online]

Available at: https://www.slideshare.net/rahimeagle/ultrasonic-pulse-velocity-test-for-concrete
[Accessed 13 november 2017].

Quavo, 2015. Pcte. [Online]

Available at: http://www.pcte.com.au/pundit-lab-ultrasonic-tester
[Accessed 13 November 2017].

Sam, 2016. Control group. [Online]

Available at: http://www.controls-group.com/eng/concrete-testing-equipment/ultrasonic-pulse-
velocity-tester.php
[Accessed 13 November 2017].

samueal, 2016. sciencedirect. [Online]

Available at: http://www.sciencedirect.com/science/article/pii/S0963869514001066
[Accessed 13 November 2017].

21