PERFORMANCE OF CONCRETE WITH UNCRUSHED PALM OIL SHELL
AS COARSE AGGREGATE
TAI KAH MON
A project report submitted in partial fulfillment of the
requirements for the award of the degree of
Master of Engineering (Civil – Structure)
Faculty of Civil Engineering
Universiti Teknologi Malaysia
JAN 2012
iii
To My Beloved Family and Friends
iv
ACKNOWLEDGMENT
In the process of preparing and completing this project, I was in contact
either directly or indirectly with many people, researchers, academicians, and
practitioners. They have contributed towards my understanding and thoughts.
In particular, I wish to express my sincere appreciation to my project
supervisor, Associate Professor Dr. Abdul Rahman Bin Mohd Sam, for his guidance,
advices and motivation. Without his continued support and interest, this thesis
would not have been the same as presented here. Besides, I also thanks to the Kilang
Alaf, supplier who provide the palm oil shells for completing this project.
Also, I have my parents to thank for its great success. Their unwavering
support has kept my faith to finish this. Such a positive response from them proves
that I’m worth to work hard of this. My sincere appreciation also extends to my
siblings and my beloved family and friends who have always giving me their point
of views. Without their continued support and interest, this thesis would not succeed
in time.
Finally, I hope that my findings in this research will expand the knowledge
in this field and contribute to all of us in future.
v
ABSTRACT
Malaysia is one of the largest producers of palm oil, contributing about 21
million tons of oil palm products in the export sector. During the process in
extracting oil palm, million tons of palm oil shells (POS) as solid wastes were
generated. The natural resources of coarse aggregate may be depleted in some day,
and the POS as wastes can cause the pollution. In this study, uncrushed POS as
aggregate replacement in concrete was studied to determine its performances. A
total of 54 concrete cubes and prisms were cast and tested. The workability,
apparent dry-density, compressive strength, flexural strength of POS concrete was
determined. The findings show that the compressive strength and density of POS
concrete was lower than the normal weight concrete. Only the full replacement of
the POS concrete was considered as lightweight concrete as the density was lower
than 2000 kg/m3. Besides, a total of 4 under-reinforced concrete beams were cast
with the dimensions of 125 x 150 x 1600 mm, and tested to failure under four-point
loading. The behaviour of the beams were studied through their load-deflection
characteristic upon loading, cracking history, and mode of failure. From the result,
the flexural behaviour of POS concrete beam was almost same with the normal
weight concrete. The cracking pattern of the POS concrete beam was comparable
with the control beam. However, the flexural strength of the POS concrete beam
was lower compared with the control beam due to the weak bonding of the POS
aggregates and cement paste. Overall results indicate that the POS concrete have a
sufficient compressive strength that required by the ASTM C330 for lightweight
structural concrete and can be used for lightweight partition in order to reduce the
member selfweight.
vi
ABSTRAK
Malaysia merupakan salah satu pengeluar minyak kelapa sawit yang terbesar,
iaitu menyumbang kira-kira 21 juta tan minyak kelapa sawit dalam sektor eksport.
Semasa pemprosesan minyak kelapa sawit, berjuta-juta tan tempurung kelapa sawit
akan dihasilkan sebagai sisa pepejal. Sumber-sumber asli bagi agregat boleh habis
pada suatu hari nanti dan tempurung kelapa sawit (POS) sebagai bahan buangan
boleh menyebabkan pencemaran. Dalam kajian ini, “uncrushed POS” sebagai
pengganti agregat dalam konkrit dikaji untuk menentukan prestasinya. Sebanyak 54
kiub dan prisma konkrit telah dibuat dan diuji. Kebolehkerjaan, ketumpatan kering,
kekuatan mampatan, kekuatan lenturan konkrit POS telah ditentukan. Hasil kajian
menunjukkan bahawa kekuatan mampatan dan ketumpatan konkrit POS adalah
lebih rendah daripada konkrit biasa. Hanya penggantian penuh konkrit POS boleh
dianggapkan sebagai konkrit ringan kerana ketumpatannya adalah lebih rendah
daripada 2000 kg/m3. Di samping itu, sebanyak 4 rasuk konkrit bertetulang telah
dibuat dengan dimensi 125 x 150 x 1600 mm, dan diuji di bawah ujian beban empat
titik sehingga gagal. Kelakunan rasuk dikaji melalui ciri-ciri seperti beban-pesongan
apabila dibebankan, corak keretakkan, dan bentuk kegagalan. Dari hasil kajian,
kelakunan lenturan rasuk konkrit POS adalah hampir sama dengan konkrit kawalan.
Corak keretakan rasuk konkrit POS adalah setanding dengan rasuk kawalan.
Walaubagaimanapun, beban muktamad lenturan rasuk konkrit POS adalah lebih
rendah berbanding dengan rasuk kawalan disebabkan ikatan yang lemah antara POS
agregat dan simen. Hasil kajian keseluruhannya menunjukkan bahawa konkrit POS
mempunyai kekuatan mampatan yang cukup seperti yang dikehendaki oleh ASTM
C330 untuk konkrit ringan dan boleh digunakan sebagai “partition” untuk
mengurangkan berat badan struktur.
vii
CONTENT
CHAPTER
CHAPTER I
TITLE
PAGE
TITLE
i
DECLARATION
ii
DEDICATION
iii
ACKNOWLEDGEMENT
iv
ABSTRACT
v
ABSTRAK
vi
CONTENT
vii
LIST OF TABLES
xii
LIST OF FIGURES
xiv
INTRODUCTION
1.1
Background of Palm Oil Shell Concrete
1
1.2
Problem Statement
3
1.3
Objectives of Study
5
1.4
Scope of Study
5
viii
CHAPTER II
LITERATURE REVIEW
2.1
Historical Background of Lightweight
Aggregate Concrete
6
2.2
Lightweight Concrete
7
2.3
Lightweight Aggregate
8
2.3.1 Natural Lightweight Aggregates
8
2.3.1.1 Volcanic Origin
8
2.3.1.2 Organic Origin
9
2.3.2 Synthetic Aggregate
10
Production of Lightweight Aggregates
10
2.4.1 Palm Oil Shells
11
2.5
Palm Oil Industry in Malaysia
12
2.6
The Palm Oil
13
2.7
Properties of Palm Oil Shells (POS)
15
2.8
Properties of Fresh Lightweight
2.4
Concrete Using Palm Oil Shells
2.9
2.10
Properties of Harden Lightweight
Concrete Using Palm Oil Shells
21
2.9.1 Compressive Strength
21
2.9.2 Flexural strength
24
2.9.3 Creep
25
2.9.4 Drying Shrinkage
26
2.9.5 Sound Absorption
28
2.9.6 Thermal Conductivity
28
Comparisons of Palm Oil
Shells with other Agricultural Wastes
2.11
19
30
Previous Studies on Palm Oil
Shells Concrete
31
2.11.1 Study 1
31
2.11.2 Study 2
34
ix
CHAPTER III
2.11.3 Study 3
39
2.11.4 Study 4
42
METHODOLOGY
3.1
Introduction
45
3.2
Experimental Program
46
3.3
Sieve Analysis
49
3.4
Design of Reinforced Concrete Beam
50
3.5
Laboratory Works
50
3.5.1 Materials of Concrete
50
3.5.2 Reinforcements
54
3.5.3 Formwork
56
3.5.4 Concrete Mixing
57
3.5.5 Placing Fresh Concrete
57
3.5.6 Curing
58
3.5.7 Installation of Demec Disc
59
Laboratory Test
59
3.6.1 Sieve Analysis
60
3.6
3.6.2 Compressive Test on
POS Aggregates
60
3.6.3 Trial Mix
60
3.6.4 Slump Test
60
3.6.5 Apparent Air-Dry Density
of Concrete Cube
61
3.6.6 Ultrasonic Pulse
Velocity (UPV) Test
61
3.6.7 Cube Test
62
3.6.8 Flexural Strength Test on Prisms
62
3.6.9 Flexural Strength Test on
x
Concrete Beams
CHAPTER IV
63
RESULTS AND ANALYSIS
4.1
Introduction
65
4.2
Sieve Analysis
66
4.3
Compressive Strength Test of POS
Aggregates and Conventional
Coarse Aggregates
69
4.4
Slump Test
71
4.5
Apparent Density of Concrete Cube
72
4.6
Ultrasonic Pulse Velocity Test (UPV Test) 77
4.7
Cube Test
78
4.8
Flexural Strength Test of Prisms
87
4.9
Flexural Strength Test on Beam
94
4.9.1 Load-Deflection of
Concrete Beams
CHAPTER V
94
4.9.2 Bonding Behaviour
97
4.9.3 Concrete Strain Distribution
101
4.9.4 Cracking Behaviour
102
4.9.5 Neutral Axis
104
4.9.6 Mode of Failure
107
CONCLUSION AND RECOMMENDATION
5.1
Conclusion
109
5.2
Recommendation
110
xi
REFERENCES
APPENDIX A
APPENDIX B
APPENDIX C
xii
LIST OF TABLES
TABLE
2.1
TITLE
Summary on the Performance of the Malaysian
Oil Palm Industry in 2008
2.2
PAGE
12
Mechanical Properties of POS, Crushed Granite
and River Sand
17
2.3
Chemical Composition of POS Aggregate
18
2.4
Compressive and Tensile Strengths of Lightweight
Concrete Using Agricultural Waste as Aggregates
30
2.5
Test Beam Details
32
2.6
Curing Regimes
35
2.7
Time to Corrosion Initiation
36
2.8
Curing Conditions for Both POS Concrete and
Controlled Concrete
2.9
40
Curing Conditions for both POS Concrete and
Controlled Concrete
43
3.1
Mix proportion of concrete with water-cement ratio 0.52
47
3.2
Mix Proportion of Concrete with w/c 0.45 and 0.4
Respectively
48
3.3
Sample Specimen for Compression Test
48
3.4
Sample Specimen for Bending Test
49
3.5
Beam Specimen for Flexural Test
49
4.1
Sieve Analysis Result of Fine Aggregates
66
xiii
4.2
Sieve Analysis Result of Conventional
Coarse Aggregates
67
4.3
Sieve Analysis Result of POS Aggregates
67
4.4
Peak Load Carried by POS and Conventional
Coarse Aggregates
70
4.5
Workability of Fresh Concrete
71
4.6
Density of Samples with w/c 0.52
73
4.7
Density of Concrete Cube with w/c of 0.45 and 0.40
76
4.8
Density of Concrete Cube at Ages of 28 days
76
4.9
Results of UPV Test
77
4.10
Compressive Strength of Concrete Cube for
Trial Mix and Design
4.11
81
Compressive Strength of CB0.5POS and CB1.0POS
with w/c of 0.45 and 0.40 respectively
84
4.12
Flexural Strength of Concrete Prisms
89
4.13
Ultimate Loads, First Crack Load and Maximum
Deflection at the Ultimate Load
95
4.14
Characteristic of Cracks
102
4.15
Cracks Spacing Pattern for All Beams
102
4.16
Mode of Failure for Concrete Beam Specimens
107
xiv
LIST OF FIGURES
FIGURE
TITLE
PAGE
2.1
Fresh Fruit Bunches
14
2.2
Cross Section of the Palm Oil Fruit
14
2.3
Types of the Palm Oil Fruits
15
2.4
Sieve Analysis for River and POS Aggregate
19
2.5
Development of Compressive Strength of POS Concrete
23
2.6
Crack paths (a) at earlier stages (b) at later stages
23
2.7
Development of the Flexural Strength with Age
25
2.8
Variation of Flexural Strength with Water-Cement Ratio
25
2.9
Experimental Moment-Deflection Curve
for Singly Reinforced Beams
2.10
Experimental Moment-Deflection Curve
for Doubly Reinforced Beams
2.11
36
Sorptivity of POS Concrete under Different
Curing Conditions
2.13
33
Volume of Permeable Voids of POS Concrete
Under Different Conditions
2.12
33
37
Water Permeability of POS Concrete
under Different Curing Conditions
37
2.14
Profile in POS Concrete under Different Curing Conditions 38
2.15
Variation of RCPT Values for POS Concrete under
Different Curing Conditions
38
xv
2.16
Variation of Ultrasonic Pulse Velocity with
Curing Age of POS Concrete under Six
Types of Curing Environment
2.17
40
Variation of Ultrasonic Pulse Velocity with Curing
Age of Controlled Concrete under Six Types of Curing
Environment
2.18
41
Relationship between the Compressive Strength
and the Curing Age of the POS concrete under
6 types of Curing Conditions
2.19
41
Relationship between the Compressive Strength
and the Curing Age of the Controlled Concrete
under 6 types of Curing Conditions
2.20
Development of Compressive Strength of
POS Concrete with Different Curing Conditions
2.21
42
44
Development of Compressive Strength of
Controlled Concrete with Different Curing Conditions
44
3.1
Cement
52
3.2
Fly Ash
52
3.3
Uncrushed Palm Oil Shell
52
3.4
Air-Dry Sand
53
3.5
Pre-soaked of POS Aggregates in Water
53
3.6
Air-Dry POS Aggregates
54
3.7
Strain Gauge with N1 Glue
55
3.8
Bitumen Film on the Strain Gauge
55
3.9
25 mm Spacer
55
3.10
Reinforcement Cage
56
3.11
Reinforcement Bar in Formwork
56
3.12
Finishing Surface of Concrete Cubes
58
3.13
Curing of Concrete Beams
58
3.14
Demec Disc on Concrete Beam Surface
59
xvi
3.15
Slump Test
61
3.16
Compressive Strength Test of Concrete Cube
62
3.17
Flexural Test and Component Equipments
64
3.18
Arrangement of Components on Concrete Beam
64
4.1
Sieve Analysis for Fine Aggregate
68
4.2
Grading for POS and Conventional Coarse Aggregate
68
4.3
Sieve Analysis for Fine Aggregates,
Coarse Aggregates and POS Aggregates
69
4.4
Failure Mode of POS Aggregates
70
4.5
Failure Mode of Conventional Coarse Aggregates
71
4.6
Workability of Fresh Concrete
72
4.7
Comparisons of Time Taken for Specimens
78
4.8
Development Compressive Strength of Concrete Cubes
84
4.9
Comparisons Compressive Strength with different w/c
85
4.10
Failure Mode of Control Cube at the age of 7 days
(left) and age of 28 days (right)
4.11
Failure Mode of CB0.5POS at the age of 7 days
(left) and age of 28 days (right)
4.12
85
86
Failure Mode of CB1.0POS at the age of 7 days
(left) and age of 28 days (right)
86
4.13
Development of Flexural Strength of Concrete Prism
92
4.14
Failure Mode of Prism without POS aggregates
(left) and Prism with POS aggregates (right)
92
4.15
Fibres on the Surface of POS Aggregates
92
4.16
Failure Mode of Controlled Prism at age of 7 days
(left) and at age of 28 days (right)
4.17
Failure Mode of CP0.5POS at age of 7 days
(left) and at age of 28 days (right)
4.18
4.19
93
93
Failure Mode of CP1.0POS at age of 7 days
(left) and at age of 28 days (right)
94
Flexural Behaviour of All Concrete Beams
95
xvii
4.20
Graph Load versus Strain for Beam BC0.0POS
99
4.21
Graph Load versus Strain for Beam BC0.0POSFA
99
4.22
Graph Load versus Strain for Beam BC0.5POS
100
4.23
Graph Load versus Strain for Beam BC1.0POS
100
4.24
Load versus Concrete Strain
101
4.25
Cracking Patterns for All Beam Specimens
104
4.26
Location of Neutral Axis for Beam BC0.0POS
105
4.27
Location of Neutral Axis for Beam BC0.0POSFA
105
4.28
Location of Neutral Axis for Beam BC0.5POS
106
4.29
Location of Neutral Axis for Beam BC1.0POS
106
4.30
Failure Mode of Beam BC0.0POS
107
4.31
Failure Mode of Beam BC0.0POSFA
108
4.32
Failure Mode of Beam BC0.5POS
108
4.33
Failure Mode of Beam BC1.0POS
108
CHAPTER I
INTRODUCTION
1.1
Background of Palm Oil Shell Concrete
Concrete is composite materials that contain cement that acts as binders and
other cementitious material, coarse aggregate such as the granite stone, fine
aggregate such as the sand and some more may contain the chemical admixtures
such as water reducing chemicals.
However, palm oil shell concrete is different compared with the
conventional concrete in terms of the constituents’ materials. Palm oil shell concrete
is composite materials that contain cement as the binder, cementitious material, fine
aggregate such as sand, but the coarse aggregate replaced by the palm oil shell.
Hence, the palm oil shells acts as coarse aggregate in this type of concrete.
Malaysia is well known for the palm oil industries and is one of the largest
palm oil producers and exporter in the world [1]. In 2009, total productions of the
2
oil palms are about 29 million tons, whereas in the export sector, it contributes about
21 million tons of oil palm products [2]. Although the palm oil industries can give
economical advantages to the country, but excessive waste products are generated
and left to rot in large amounts and sometimes disposed through incineration which
can cause pollution to the environment.
Since the palm oil shell is a byproduct during the extraction process of oil
palm fruitlets, hence, it can be categorized as organic materials that can be
deteriorated with the time. However, these oil palm shells will not contaminate or
leach to produce toxic substance once it bound inside the concrete [3].
The palm oil shells obtained can be crushed type or uncrushed type. The
crushed palm oil shells have irregular shapes and different sizes of shells, different
thickness of the shell and having low density compared with the conventional
aggregate. Whereas for the uncrushed palm oil shell, the shapes are spherical and it
can be smooth or rough depend on the extraction process.
Besides, the properties of the palm oil shell are very different from the
conventional aggregates. These shells have high porosity compared to conventional
aggregates, hence it will have a low bulk density and having a high water absorption
capacity [4].
The low bulk density of the palm oil shells can produce lightweight hardened
concrete. These lightweight concretes are very useful in construction industry since
the lightweight concrete can reduce the self weight of structural members. Thus, it
can reduce the dead load of the structure and reduce the use of reinforcement steel.
This results the overall cost reduction in construction industries [1].
3
In addition, palm oil shells do not need any chemical pretreatment compared
with the artificially produced lightweight aggregate before it is used [5]. The palm
oil shell concrete can easily attain the strength of more than 17 MPa which is a
requirement of structural lightweight concrete as ASTM C330 [6].
Palm oil shells can be used to as the road base material especially in palm oil
estate to reduce the cost in buying the granite stone to construct crusher run. Besides,
palm oil shell concrete can be used for the construction of low cost houses. The oil
palm shell used to make the hollow blocks for the walls and the oil palm shell
concrete used to construct the footings, lintels and beams. These has been done in
Universiti Malaysia Sabah (UMS) in 2003 and these structures are still performing
well and has no structural problems [7].
1.2
Problem Statement
With the continual use of natural resources aggregate in the production of
concrete which consume a lot of it, the resources will be depleted someday. The
prices of the conventional aggregate begin to increase due to the limited resources
and the process involved in crushing the aggregate. This will create an economy
chain that will cause the prices of housing increases, and not only the housing, other
products’ prices will also increase due to the indirect effects. In ensuring the
availability of resources in future, steps must be taken to conserve the nonrenewable resources and energy.
In other industries, especially the agro-based industries, abundant wastes are
produced and treated improper way will cause the pollution to the environment [1].
The untreated waste can pollute the land, water and air via leaching, dusting and
volatilization. Legislatives are needed to be determined in order to control and
4
minimized the pollutants released to other areas [6]. But if these wastes are
investigated and studied, these wastes have a potential to be used as construction
material.
Recycling and utilization of agricultural waste and industrial by-products are
very beneficial to our environment and industry. Increasing of the wastes products,
resources preservation and material cost has result in the utilization of solid wastes.
Material recovery from the agricultural wastes and industrial waste into reusable
materials not only can protect the environment, but also can preserve the natural
resources since the natural resources are limited [6].
Malaysia, the second largest oil palms producer and exporter in the world,
produce more than 4 million tons of palm oil shells during the process of palm oil
extraction annually [5]. These oil palm shells, as a waste product of the extraction
process, being left at the mill to rot in a large amount and some of the wastes are
being disposed through incineration. This will cause pollution to the environment
indirectly [5].
As the natural resources are being depleted and the pollution cause by the
palm oil shell are getting serious, this situation justify the investigation and studies
need to be done on the suitability of palm oil shell as a replacement of conventional
aggregate in concrete. Hence, this study is carried out to investigate the performance
of concrete with uncrushed palm oil shell as aggregate.
5
1.3
Objectives of Study
The purpose of this study is to investigate the performance of concrete with
uncrushed palm oil shells (UCPOS) as aggregates. Objectives of this study are as
follow.
i.)
To study the workability of the fresh UCPOS concrete
ii.)
To study the dry-density of UCPOS concrete
iii.)
To study the compressive strength and flexural strength of the UCPOS
concrete with different percentage of UCPOS replacement.
iv.)
To study the flexural behavior of UCPOS concrete beam.
1.4
Scope of Study
The scope of this research will cover the application of the uncrushed palm
oil shells (UCPOS) as aggregates, where the conventional aggregates in normal
weight concrete will be replaced by the palm oil shells by percentage. Tests will be
carried out to determine the performance of palm oil shell concrete. Data to be
collected include:
i.)
Workability of the fresh palm oil shell concrete
ii.)
Compressive strength and flexural strength of palm oil shell concrete with
different percentage of UCPOS replacement
iii.)
Flexural strength of the palm oil shell concrete beam
iv.)
Load-deflection characteristics of the UCPOS concrete beam
v.)
Mode of structural failure of UCPOS concrete beam
CHAPTER II
LITERATURE REVIEW
2.1
Historical Background of Lightweight Aggregate Concrete
Lightweight aggregate concrete is not a new material invention in concrete
technology, and has been used since ancient times. Lightweight aggregate concrete
was made by using natural aggregates of volcanic origin such as pumice, scoria, etc.
Buildings made from these lightweight aggregate are Babylon in the 3rd millennium
B.C.; Roman temple, Pantheon, which was erected in the years A.D. 14; and the
great Roman amphitheatre, Colosseum, built between A.D. 70 and 82. Romans used
natural lightweight aggregate and hollow clay vases for their “Opus Caementitium”
to reduce the weight. This was also used in the construction of the Pyramids during
the Mayan period in Mexico [8].
With the increase in the demand of lightweight aggregate concrete and the
unavailability of the aggregates, technology for producing the lightweight aggregate
has developed. In Germany, porous clay pieces were produced by quick evaporation
of water, in 19th century. The industrial use of natural lightweight aggregates started
in 1845 by Ferdinand Nebel who produced masonry blocks from pumice with burnt
7
limes as the binder [9]. In Iceland, the uses of pumice in local building start in 1928
[10].
2.2
Lightweight Concrete
Nodaway, lightweight concrete includes the aerated and no-fines concrete
and defined as concrete with an air-dry density not exceeding 1850 kg/m3, compared
to normal concrete which has a density of 2300 kg/m3. Lightweight concrete has
many applications include in pre-stressed concrete and reinforced concrete [11].
Lightweight concrete can be produced by using lightweight aggregate,
omitting the fine aggregates or aeration. Combinations of the above methods are
also possible. The American institute defines the structural lightweight concrete as
concrete having air-dry density of less than 1840 kg/m3 and a compressive strength
of over 17.2 N/mm2 after 28 days. Whereas the British Code of Practice BS 8110
recommends minimum characteristic strength of 15.0 N/mm2 at 28 days [11].
Lightweight concrete is used in many applications such as structural
applications and thermal insulation applications. The advantage of lightweight
concrete is it can significantly reduce the total dead weights which mean a large
proportion of the dead load on the structure. For the lightweight concrete used in
insulation purpose, the lightweight concrete are usually under 400 kg/m3, while
structural lightweight concrete are usually range from 1600 kg/m3 to 2000 kg/m3
[11].
8
2.3
Lightweight Aggregate
Lightweight aggregate can originate from man-made or natural resources.
The major natural resources is the volcanic material whereas man-made or synthetic
are produced by thermal process in factories binder [9].
2.3.1 Natural Lightweight Aggregates
Natural lightweights aggregate are mostly of volcanic origin, thus are only
found in certain parts of the world. Pumice and scoria are the oldest known
lightweight aggregate. These aggregates are light and strong to be used in natural
state, but having different properties.
2.3.1.1 Volcanic Origin
In volcanic origin, when the lava from a volcano cools down, it will produce
a spongy well-sintered mass. When sudden cooling of molten magma mass, the
material will freezes. If sudden cooling of the molten magma, crystallization not
occur, and the material acquires a glassy structure, which similar to the process of
glass production known as obsidian. This can be called as supercooled liquid which
do not have crystalline phase. It is highly amorphous and glassy structure binder [9].
Lava is a boiling melt which may contain air and gases, and will formed
spongy porous mass when cooled down. Lava can produce lightweight material that
is porous and reactive. This material known as volcanic aggregates, or pumice or
9
scoria aggregates. The aggregates are produced by mechanical handling of lava by
crushing, sieving and grinding binder [9].
Lightweight aggregate concrete made with pumice has low density, thus lead
to relatively weight reduction of the structure and foundation, thereby reducing the
dead load. This can be significant in high rise buildings. This also can be used as
material for repairs the old buildings as it will not increase the total dead load of the
building structure.
2.3.1.2 Organic Origin
In organic aggregates, one of it is the palm oil shells. The use of agricultural
waste as aggregates for building materials has several benefits and economical
advantages. The palm oil industry is very important in many countries such as
Malaysia, Indonesia, and Nigeria, which produces a large amount of waste which
can be utilized in the production of building materials. These shells which produced
in large quantities can be used in the production of lightweight aggregate concrete.
Till now there is no commercial production of these lightweight aggregates, and
normally used in locally. There are two major advantages by using this aggregates
i.e. these aggregates have no commercial value, and as being locally, the transport
cost is cheap [9].
10
2.3.2 Synthetic Aggregate
Synthetic aggregate are produced by thermal treatment of material having
expansive properties. These materials can be divided in three groups:
i.)
Natural materials, such as perlite, vermiculite, clay, shale, and slate.
ii.)
Industrial products, such as glass.
iii.)
Industrial by-products, like fly ash, expanded slag cinder, bed ash, etc.
The most common types of lightweight aggregates produced from expansive
clays are known as Leca and Liapor. Those made from fly ash are known as Lytag.
The bulk density of the aggregate varies greatly depending upon the raw materials
and the process in their manufacturing binder [9].
2.4
Production of Lightweight Aggregates
Lightweight aggregate can occurred naturally or produced by thermal
treatment. For the aggregate occurred naturally, the aggregate are ready to be use
only after the mechanical treatment which include crushing and sieving. Some
industrial by-products, waste materials, naturally occurring materials, etc., thermal
treatments are applied in order to made them as aggregate [9].
The properties of lightweight aggregate concrete depend on the properties of
the aggregate used, which in turn depend on the type of the material and the
producing process to produce these aggregates. In lightweight aggregate concrete,
there is a vast variation in the density of the aggregate, thus, there will be a vast
variation in the strength of the lightweight aggregate concrete [9].
11
2.4.1 Palm Oil Shells
Palm oil shells are one of the naturally occurring raw materials and obtained
as a byproduct when palm oil is extracted from the palm nuts. The palm oil tree,
which the palm oil shell is extracted from, is a type of wet tropical tree, which found
mostly around the equatorial zone [12].
The species of palm oil tree normally found in Malaysia are oleifera, dura,
psifera, and tenera. The shells comprise about 10% to 50% of the total composition
of oil palm fruitlets, except for the psifera species which has virtually no shell to the
kernel [4]. Palm oil shells are agriculture wastes which are renewable and occurring
abundance in some countries, and begin interested in alternative to the traditional
building materials particularly for low cost construction [9].
The agricultural waste as aggregates can be used as an alternative to
conventional construction material in producing the lightweight aggregate concrete.
These agricultural wastes are produced in a large quantity from the palm oil mills
and can be used as aggregates in producing lightweight concrete. These agricultural
wastes also can be used in production of cementitious materials, its fibers can be
used in particle boards or sheets and its shell can be used as aggregates [11].
The material properties and structural performance of lightweight concrete
made from palm oil shell are found to be similar with the lightweight concrete made
from common aggregates such as clinker, foamed slag, and expanded clay. The
palm oil shells are hard and crushed as a result of the process of extracting the oil.
Sieving is needed in order to remove the fine particles. After sieving, the shells are
air-dried before used in concrete mixing [9].
12
2.5
Palm Oil Industry in Malaysia
Malaysia is one of the largest production palm oil, contributing about 29
million tons in the year of 2008. Table 2.1 shows the summary on the performance
of the Malaysian Oil Palm Industry in the year of 2008.
Table 2.1:
Summary on the Performance of the Malaysian Oil Palm Industry in
2008 [2]
Year
2008
PLANTING (hectares)
Area
4,487,957
PRODUCTION (tones)
Crude palm oil
17,734,439
Palm kernel
4,577,500
Crude palm kernel oil
2,131,399
Palm kernel cake
2,358,732
Oleochemical products
2,207,994
EXPORTS (tones)
Palm oil
15,408,753
Palm kernel oil
1,047,380
Palm kernel cake
2,255,092
Oleochemical products
2,072,221
Biodiesel
182,108
Finished products
670,569
Others
113,951
TOTAL EXPORTS (tones)
21,750,074
13
2.6
The Palm Oil
Elaeis guineensis Jacq. which is generally known as oil palm is an important
species in the genus Elaeis which belongs to the Palmae family. The second species
which is Elaeis oleifera (H.B.K) Cortes is found in the south and central of America,
and generally known as American oil palm [13].
The palm oil is an erect monoecious plant that produces both separate female
and male inflorescences. This palm trees are cross-pollinated and the weevil act as
the pollinating agent. The harvesting can started after 24 to 30 months of planting
and each palm can produce in the range of eight to fifth-teen fresh fruit bunches per
year. Each fresh fruit bunches can contain about 1000 to 1300 fruitlets. Figure 2.1
shows the fresh fruit bunches of oil palm. Each fruitlets consists of a fibrous
mesocarp layer and the endocarp which is the shell that contain the kernel [13].
The common cultivars are the Dura, Tenera and Pisifera which are classified
by the thickness of the endocarp or shell and the mesocarp content. Dura palms
have an endocarp thickness of 2-8mm and a medium mesocarp content which
consist the 35%-55% of fruit weight. The tenera race has an endocarp thickness of
0.5-3mm thick and high mesocarp content of 60%-95%. The pisifera palms do not
have endocarp and have about 95% of mesocarp [14]. Figure 2.2 shows the cross
section of the palm oil fruit. Figure 2.3 shows the type of the palm oil fruits.
The palm oil produces two types of oils. The fibrous mesocarp produces the
palm oil whereas the palm kernel produces the lauric oil. In the conventional milling
process, the fresh fruit bunches are sterilized, then the fruitlets are stripped off, then
digested and pressed to extract the crude palm oil. The nuts separated from the fiber
in the press cake and cracked to obtain the palm kernels. The palm kernel then
14
crushed in another plant to obtain the crude palm kernel oil and a byproduct, palm
kernel cake which is used as animal feed. Palm oil has a balanced ratio of saturated
and unsaturated fatty acids whereas the palm kernel oil has saturated fatty acids
almost the same with the composition of coconut oil [13].
Figure 2.1:
Figure 2.2:
Fresh Fruit Bunches [13]
Cross Section of the Palm Oil Fruit [13], [15].
15
Figure 2.3:
2.7
Types of the Palm Oil Fruits [15]
Properties of Palm Oil Shells (POS)
Palm oil shells is a type of agricultural solid wastes and as being an organic
material, it can be biodegradable and decay over a long period of time if the
environment is full with moisture and sufficient air are present [16]. Presently, the
uses of palm oil shell are limited to the fuel for burning and as finishes in mud
houses. The shells can provide several advantages if it was found to be structurally
adequate. Such advantages include the low density of the shells which can reduce
the self weight of the material, good thermal insulation and good sound absorption
[12].
Palm oil shells are dark grey to black in color. The shell has two faces that
are outer face and inner face. The outer face are from which the fibers and palm oil
has been extracted, and this face can be smooth or rough depend on the extraction
process. The inner faces are from which the kernel are extracted, and this face is
relatively smooth [12].
16
The shells also have irregular shapes such as angular or polygonal,
depending on the extraction process. Besides, the thickness of the shells is variable
and can range from 0.15 to about 3mm, depend on the species and the time of year
[12]. Sometimes, the oil coating can present on the surface of fresh palm oil shells,
therefore, pretreatment to remove this oil coating are necessary. The pretreatment
can be done via various ways, including natural weathering, boiling in water, and
washing with detergent [4].
The mechanical properties of palm oil shell, crushed granite and sand are
shown in Table 2.2. From the Table 2.2, it shows that the shell has higher water
absorption with a capacity of 23.3%. This high water absorption may due to the high
porosity in the shell. This shows that the shell need more water compared to the
conventional aggregate to attain the same consistency [12]. Since the shell has
higher water absorption, the shells need to be pre-soaked in potable water for 24
hour to achieve saturated surface dry (SSD) condition before mixing. This is to
prevent the absorption from occurring during the mixing [7].
From Table 2.2, the aggregate impact value (AIV) and the aggregate
abrasion value of POS aggregates are having more lower value compared to the
conventional crushed stone aggregate, which indicate that the POS aggregate have
good absorbance to shock. The abrasion value of the shell determine from the Los
Angeles abrasion test was 4.80% [7]. This value was lower than the 24.0% obtained
for the granite which is normal weight aggregate. The abrasion value of aggregate
shows the wear resistance of aggregate. The lower value shows that the aggregate
has higher wear resistance, hence, it shows that the POS aggregate have good
resistance to wear compared to conventional aggregate. This property of the shell
has been exploited by forefathers as floor finishes in mud house. Evidence shows
that the floor is still existence to date, despite the structure has severely deteriorated
for many years. Most of the house are not inhabited and not maintained, but the
floor is still relatively in good condition [12].
17
As shown in Table 2.2, the specific gravity of the shell was found to be 1.17.
The specific gravity are depends on the specific gravity of the minerals of which the
aggregate is composed and the voids. The shell has a bulk unit weight of 500-600
kg/m3, thus, this place the POS within the range of the bulk density of lightweight
aggregate. The bulk density of the lightweight aggregate can vary from 300 to 1100
kg/m3 [17]. Hence, the palm oil shell can be classified as lightweight aggregate [12].
Figure 2.4 shows the results of sieve analysis for the river sand and POS aggregate.
Before the POS being used as aggregate, they were sieved and only aggregates
passing through the 12.5mm sieve and retained on the 4.75mm sieve was used in
mixing [7], [4].
In addition, the chemical properties of the oil palm shells also determined
and presented in Table 2.3.
Table 2.2:
Mechanical Properties of POS, Crushed Granite and River Sand [18].
Properties
Palm
oil
(POS)
shell
Crushed granite
River sand
Specific gravity
1.17
2.61
2.60
Flakiness index (%)
65.17
24.94
-
12.36
33.38
-
590
1470
-
6.24
6.33
2.56
4.80
24
-
7.86
17.29
-
Elongation index
(%)
Bulk unit weight
(kg/m3)
Fineness modulus
Los Angeles
abrasion value (%)
Aggregate impact
value (%)
18
Table 2.2:
Loss on ignition
24-h water
absorption (%)
Table 2.3:
Elements
(continues)
100
-
-
23.30
0.76
0.95
Chemical Composition of POS Aggregate [7]
Results (%)
Ash
1.53
Nitrogen (as N)
0.41
Sulphur (as S)
0.000783
Calcium (as CaO)
0.0765
Magnesium (as MgO)
0.0352
Sodium (as Na2O)
0.00156
Potassium (as K2O)
0.00042
Aluminium (as Al2 O3)
0.130
Iron (as Fe2O3)
0.0333
Silica (as SiO2)
0.0146
Chloride (as Cl-)
0.00072
Loss on Ignition
98.5
19
Figure 2.4:
2.8
Sieve Analysis for River and POS Aggregate [7].
Properties of Fresh Lightweight Concrete Using Palm Oil Shells
As the result of crushing during extracting the oil from the palm nut, the hard
palm oil shells are received as crushed pieces. A lot of fine particles were produced,
hence, the sieving process are needed to remove the large amount of fine particles.
After the sieving process, the shells then air-dried before use in concrete mixing [11].
Since the palm oil shells are lighter than the cement matrix, it tends to
segregate in the wet concrete mixes. Trial mixes are normally necessary to achieve a
good mix design [11].
The workability of freshly mixed concrete depend on the mix proportions,
the materials and environmental conditions. The aggregate normally occupy about
70% of the total volume of the concrete. The total specific areas of the aggregate are
minimized by proper selection of the size, proportion of the fine and coarse
20
aggregate, and the shape of aggregates. The surface texture and the shape of
aggregates affect the void content and the water requirement of the concrete mixing.
The fineness modulus of aggregate is a numerical index of the fineness which
indicates the mean size of that aggregate. The fineness modulus of aggregate is a
prime indication in obtaining the required strength and workability which can give
the most economic mix design [6].
The workability of fresh concrete and bonds between the mortar phase and
the aggregate are influenced by the physical characteristic of the aggregate such as
the roughness, texture and shapes. The surface texture of the aggregate can be
smooth or rough; whereas the surface can be glassy, smooth, granular, rough,
crystalline, and porous [19]. The roughness and the porosity of the surface of the
aggregate affect the development of the bond. The porous surface of the aggregate
can improve the development of bond by the suction of the paste into its pores [6].
A study was done by a group of researchers on the workability of fresh
concrete with palm oil shells as aggregates. The results showed that the POS
concrete has better workability than that of the normal concrete. In the same watercement ratio, the smooth surface of the palm oil shells may has led to a better
workability, slump and compaction factor when compared with the normal concrete
[6]. This similar trends also being reported that the presence of palm kernel shell as
aggregate can lead to better workability for a same water-cement ratio [20]. The
addition of fly ash in POS concrete did not show any significant difference in
workability [6].
However as the percentage of the POS replacement increase, the slump of
the concrete will decrease [1]. This may due to the higher shells content combined
with the irregular and angular shapes of the shells lead to poor workability. Lower
workability might also due to the friction of the angular shapes between the shells
and lower fines content [21]. Besides, the porosity of the shells can influence the
21
workability. The higher the porosity of the shells, the absorption capacity will be
higher, which consequently reduces the workability. The lower compacting values
of the shells indicate that less work is done on the shell concrete by gravity. This
may due to the lower density of the shell aggregate when compared with granite
aggregate [12].
2.9
Properties of Harden Lightweight Concrete Using Palm Oil Shells
2.9.1 Compressive Strength
The proportion of the palm oil shells and the water cement ratio normally
affect the workability and the compressive strength of the lightweight concrete with
palm oil shells as aggregate. The 28 day cube compressive strength of the
lightweight concrete are found to be vary in the range of 5.0 to 19.5 N/mm2 [11].
The compressive strength of concrete with POS was found continue to
increase with age. This shows that the POS do not undergo any degradation after
mixed with the concrete matrix. Besides, study was done by other researchers that
the compressive strength of the POS concrete at 28 day was higher than the
minimum required strength of 17 MPa as stipulated by ACI 318 (1995) for
structural purposes [1].
Even though the compressive strength of the POS concrete continues to
develop with age, but still remained below that of the normal concrete. The
development of the compressive strength of POS concrete was about 49-55% lower
compared with the normal concrete [6]. Although the POS aggregate is a type of
organic material, but study was done by other researchers showing that the
22
biological decay was not evident as the concrete cubes gained strength even after 6
months [4]. Figure 2.5 shows the development of compressive strength of POS
concrete.
At the early ages, the compression failure pattern of POS concrete was
governed by the POS aggregate. The failure was due to the breakdown of the bond
between the POS aggregate and the cement paste. This shows that the strength of the
bond was not strong because of the organic effect and smoothness of the POS
surface [6]. This situation maybe can be overcome if the POS aggregate were treated
with lime solution before mixing [22]. However, at the later ages, the failure pattern
was more governed by the strength of the POS aggregate-paste bond than the POS
aggregate itself. Figure 2.6 shows the crack paths of the POS concrete at the early
ages and later ages.
In most cases, the lower the density, the strength will be lower [23]. The
POS concrete were lighter than the normal concrete, thus, the strength of POS
concrete were lower than the normal concrete. Besides, the porosity also affects the
compressive strength of POS concrete. POS concrete were found to have higher
porosity compared with normal concrete. Furthermore, the physical properties of the
POS aggregate such as the strength, the thickness, stiffness and density, are lower
than the crushed stone aggregate which govern the compressive strength of the
concrete [6]. The development of the compressive strength was also affected by the
shapes of the POS aggregate [24].
Generally, the compressive strength is controlled by both the strength of
aggregate and the strength of paste, but depends on which of them failed first. When
the free water-cement ratio were the same, the lightweight aggregate requires higher
water content for absorption compared with the normal weight concrete. For a given
workability, the compressive strength increase with cement content as well as the
type of aggregate used. Thus, the development of the compressive strength of POS
23
concrete was lower than normal concrete [6]. Hence, the concrete strength depends
on the stiffness, strength and density of coarse aggregates [18].
Figure 2.5:
Development of Compressive Strength of POS Concrete [20].
Figure 2.6:
Crack paths (a) at earlier stages (b) at later stages [4].
24
2.9.2 Flexural strength
Reinforced concrete beam made from palm oil shells are found to be
exhibited satisfactory in structural behavior. With a lightweight concrete mix of
1:1.5:0.5/0.5 cement, sand, palm oil shells and water-to-cement ratio, a 28 day cube
compressive strength are found about 17.5 N/mm2 [11].
Study done by other researchers has shown that the 28 day flexural strength
of OPS concrete was about 14% to 17% of the compressive strength whereas for
normal concrete, the flexural strength is about 13% to 15%. This shows that the
behavior of the OPS concrete is similar with the normal concrete [18]. However,
the flexural strength of concrete with OPS is weak in resisting bending stress
compared with the normal concrete [1]. These flexural strength values obtained still
fall within the normal range of the conventional concretes, in which the flexural
strength is about 10 to 23% of its compressive strength [25].
The flexural strength of concrete depends on physical strength of coarse
aggregate to some extent, just like compressive strength [18]. Besides, the flexural
strength is influenced by the diffused moisture distribution in the test samples
significantly [26]. As the density decrease, the flexural strength also decrease [12].
Figure 2.7 shows the development of the flexural strength with age. The trends are
very similar with the compressive and tensile splitting strengths. Figure 2.8 shows
the development of flexural strength for 7 and 28 days curing.
25
Figure 2.7:
Figure 2.8:
Development of the Flexural Strength with Age [27].
Variation of Flexural Strength with Water-Cement Ratio [12].
2.9.3 Creep
A load equivalent to a stress of 6.0 N/mm2 are applied on three 150 mm
diameter cylinders made from lightweight concrete with palm oil shell as aggregates
26
in order to perform the creep test according to ASTM. The strain obtained by
deducting the initial reading from the final reading immediately after loading. The
readings were taken after six hours, then daily for one week, weekly for one month
and monthly for nine months. Strain readings of the control sample were taken at the
same time schedule. The total strains then divided by the average stress giving the
total strain per unit stress. This total strain per unit stress then plotted. The results
show that the creep curve for the lightweight concrete with palm oil shells shows a
large creep compared with the ordinary concrete. The creep rate for lightweight
concrete using palm oil shells did not show a constant value after 3 months, and this
property will be concerned when used as structural lightweight concrete [11].
2.9.4 Drying Shrinkage
Generally, all the cement products undergo volume changes which are small
in values with response to the changes in moisture conditions. Although the volume
changes are small, but the effects are considerably important [28].
When a fresh concrete dried, it undergoes shrinkage which is termed as
initial drying shrinkage. After that, the concrete will subsequently experienced the
alternative wetting and drying showing the alternative expansion and contraction
which termed as reversible moisture movement [28].
The reversible moisture expansion in lightweight concrete with response to
the change in moisture condition is found that more often than but not as great as the
initial drying shrinkage [28]. Recent study [29] shows that not only the cement
undergo the shrinkage, but a few natural aggregate have shown marked shrinkage
that contribute the total shrinkage of the concrete [28].
27
An only cement paste without any constituents has a high drying shrinkage,
but for the concrete with its dense and hard aggregate, the drying shrinkage is
relatively small. This is because the movements are constraints by the rigidity of the
aggregates. For lightweight aggregate concrete, the drying shrinkage are high due to
the use of weaker and less rigidity of the aggregates, causing less restrained are
imposed on the cement paste. The drying shrinkage of the lightweight aggregate
concrete are about twice that of the observed in heavy concrete [28].
The shrinkage of lightweight concrete is about 50% greater than the normal
weight concrete [30]. Besides, concrete with the aggregate having open textured and
irregular surface can produce shrinkage of about 1000 microstrain [26]. Tensile
stress can be set up in the concrete as the result of drying shrinkage, especially it is
restrained. If the shrinkage stress exceeds the tensile strength of the concrete, crack
will occurred [28].
Study was conducted by researchers to study the drying shrinkage of the
POS concrete. It was found that the POS concrete experienced more shrinkage of
about 14% higher than the normal weight concrete. Shrinkage can be due to the loss
of free water in concrete mixture, the settlement of solids, drying of concrete and
chemical reaction of the cement paste [18].
This drying shrinkage is a long lasting process when the concrete exposed to
dry condition, same as the hydration process. There are some factors which govern
the drying shrinkage of the lightweight concrete such as the water-cement ratio,
curing temperature, moisture content, admixture, aggregate characteristic (with the
stiffness, content and volume/surface ratio), relative humidity, and the rate and
duration of drying [31], [32].
28
2.9.5 Sound Absorption
Sound absorption was measured through the noise reduction coefficient. The
sound absorption coefficient was measured at frequencies of 250, 500, 1000 and
2000 Hz which used in U.S.A moderately some time [33].
A study was conducted by researchers’ shows that the normal weight
concrete have a noise reduction coefficient of about 0.02 [34]. For the concrete with
shell as aggregates, the noise reduction coefficient is about 0.34 for water-cement
ratio of 0.5. This shows that the shell concrete which is lightweight concrete has
better sound absorption capacity than the normal weight concrete [12].
If the water-cement ratio increases, the noise reduction coefficient increased.
This may due to the increasing in the water-cement ratio that will cause the porosity
of the concrete increase as well. This enable the shell concrete as a porous material
act as a good sound absorbent. When sound energy pass through the shell concrete,
part of the energy is used up in exciting the air that held in the discrete pores within
the structure. Hence, as the porosity increase, more pores will present and this would
probably increase the absorption capacity. The sound absorption capacity of shell
concrete can be used as sound proofing in some purposes [12].
2.9.6 Thermal Conductivity
A study was conducted to obtain the thermal conductivity of shell concrete
which have a value of 0.45 Wm-1oC-1, whereas for the shell aggregate, the thermal
conductivity is 0.19 Wm-1oC-1. These values shows that both the concrete shell and
shell aggregate have low thermal conductivity. Hence, the material can be
29
considered as a poor conductor of heat. The thermal conductivity value obtained for
the shell concrete were higher when compared with the shell aggregate due to the
shell concrete have other constituents such as the fine aggregates, cement or
hydration product. These imply that these constituents conduct heat more than the
shell aggregate [12].
Thermal conductivity of normal weight concrete in saturated state lie
between 1.38 and 3.68 Wm-1oC-1 as found by Mitchell [34]. Besides, suggestion
from Loudon and Stacey states that the thermal conductivity of normal weight
concrete that tested at a moisture content of not more than 5% are in the range
between 0.707 and 2.267 Wm-1oC-1. This implies that if the determination was done
at moisture content of 5% or less than that, lower value of thermal conductivity will
be obtained, since the conductivity of water are higher than the air [12].
Furthermore, it has been stated that for the lightweight concrete, if the moisture
content increase by 10%, the thermal conductivity will be increased by one-half [17].
For the lightweight concrete, the thermal conductivity was in the range
between 0.05 and 0.69 Wm-1oC-1as reported by Neville [17]. The low thermal
conductivity of the shell concrete can be due to its high porosity. The thermal
conductivity through the poor conductor is mainly bring about by the heat waves
which produced by the lattice vibration due to the thermal motion of the molecules.
Thus, the high porosity of the shell concrete may reduced the propagation of the
waves [12]. Some of the pores contain air molecules which have low thermal
conductivity [17], and consequently reduced the heat transfer rate through the pores
[12].
30
2.10
Comparisons of Palm Oil Shells with other Agricultural Wastes
The strength properties of concrete with palm oil shells as aggregate were
compared with other lightweight concrete with other agricultural wastes as
aggregates. Four types of agricultural wastes were studied including palm oil shells,
palm oil clinkers, rice husks and coconut shells. The palm oil clinkers are the byproducts of the palm oil mills energy generating burners. Both the palm oil clinkers
and the coconut shells needed to be crushed and broken into size not larger than 20
mm before use in concrete mixing. Before using these agricultural wastes, these
aggregates wastes need to be air-dried. The concrete mixed with a ratio of 1:1:2 of
cement, sand and agricultural wastes with water-cement-ratio of 0.55. After the test,
the bulk density, compressive strength and the tensile strength of the lightweight
concrete with agricultural wastes as aggregates were summarized in Table 2.4. From
the test results, the lightweight concrete using the palm oil clinkers and palm oil
shells were found to have a higher compressive strength and tensile strengths values
[11].
Table 2.4 : Compressive and Tensile Strengths of Lightweight Concrete Using
Agricultural Waste as Aggregates [11]
Agricultural
Wastes
Bulk density
of wastes
Lightweight Concrete Strength (N/mm2)
(kg/m3)
Compressive
Tensile
7 days
28 days
28 days
830
20.7
29.8
1.37
Oil palm shell
620
12.6
17.4
1.12
Coconut shell
445
8.9
11.6
1.15
Rice husk
136
3.4
6.3
0.82
Oil
palm
clinker
31
2.11
Previous Studies on Palm Oil Shells Concrete
Many studies have been carried out on the use of palm oil shells as aggregate
in concrete. Several studies are discussed in the following section.
2.11.1 Study 1
A group of researchers has been conducted a studies on the flexural behavior of
the reinforced lightweight concrete beams made with palm oil shells [5]. In this
study, a total of 6 under reinforced concrete beams with varying reinforcement
ratios were fabricated and tested. Three of the beams were singly reinforced and the
other three were doubly reinforced. All the coarse aggregates in beams were fully
replaced by POS as coarse aggregates. From the experimental investigation, the
flexural behavior of the POS concrete was observed that almost comparable with the
other types of lightweight concrete. This observation and results encouraging the
POS used as aggregate in the production of structural lightweight concrete
especially for the low cost house. Table 2.5 shows the test beam details used in this
study. Figure 2.9 shows the experimental moment-deflection curve for singly
reinforced beams. Figure 2.10 shows the moment-deflection curve for doubly
reinforced beams. All the observations and conclusions are as follows:
i.)
All of the POS concrete beams have a typical structural behavior in flexure.
Before crushing of the compression concrete in the pure bending zone, the
yielding of reinforcement occurred, since the beams are under-reinforced.
ii.)
The deflections of the POS concrete calculated from the BS 8110 under
service loads can be used to provide reasonable prediction. For the
deflections under the service design load of the singly reinforced beams, the
deflections were within the allowable limit provided by BS 8110. For the
32
doubly reinforced beams, the deflections under the design of service loads
have exceed the limit, suggesting the beams can be increased in the depth.
iii.)
POS concrete beams in this investigation showing a good quality in ductility
behavior. All beams showed a considerable amount of deflection and this
can give enough warning to the imminence of failure.
iv.)
The crack widths at service load ranged from 0.22 mm to 0.27 mm. These
crack widths are within the maximum allowable value as required in BS
8110 for durability requirements.
Table 2.5:
Beam
no.
Beam
type
Tension
reinforcement
no. and size
Test Beam Details [5]
Nominal/
compression
reinforcement
no. and size
Beam
size,
Area of
B
tensile steel,
=
,%
x D (mm)
As (mm2)
150 x 230
157
0.52
150 x 231
226
0.75
150 x 231
339
1.13
S1
Singly
2Y10
S2
Singly
2Y12
S3
Singly
3Y12
D1
Doubly
3Y16
2Y10
150 x 233
603
2.01
D2
Doubly
3Y20
2Y16+1Y12
150 x 235
943
3.14
D3
Doubly
3Y20+2Y12
2Y20+1Y10
150 x 242
1169
3.90
2R8
33
Figure 2.9:
Experimental Moment-Deflection Curve for Singly Reinforced
Beams [5]
Figure 2.10: Experimental Moment-Deflection Curve for Doubly Reinforced
Beams [5]
34
2.11.2 Study 2
A group of researchers also investigate the durability of the lightweight POS
concrete under different curing conditions [35]. The durability properties
investigated include the volume of permeable voids (VPVs), water permeability,
chloride diffusion coefficient, sorptivity and time to corrosion initiation from the 90
day salt ponding test, and Rapid Chloride Penetrability Test (RCPT). Through this
investigation, the results obtained provide valuable information on the durability of
the lightweight concrete made from POS. The hydration process for POS concrete is
enhanced at the early stages due to the process of internal curing from the water
absorbed by the lightweight aggregate. But a proper curing is needed at the later
ages to achieve a better durability. The durability properties of the POS concrete are
found to be comparable well with the other lightweight concretes. Table 2.6 shows
the curing regimes of the specimens. Table 2.7 shows the durability properties of the
concrete in terms of the time to corrosion initiation. Figure 2.11, Figure 2.12, Figure
2.13, Figure 2.14 and Figure 2.15 show the results of the durability of the concrete
under different curing regimes. The following results show the durability properties
of POS concrete:
i.)
The VPV of POS concrete at age 28 days was found in the range of 20.121.2%.
ii.)
At age 28 days, the sorptivity of the POS concrete was about 0.06-0.14
mm/min0.5. This relatively low sorptivity was due to the high quality of the
cement paste which was produced with a low water-cement ratio of 0.38 and
well compacted POS concrete.
iii.)
At the age of 28 days, the permeability coefficient was ranged from
6.4 x 10-12 to 57.5 x 10-12.
iv.)
The chloride diffusion was ranged from 5.86 x 10-8 to 12.02 x 10-8 cm2/s.
v.)
The time to corrosion can be enhanced when the cover was adequate and the
proper curing is adopted.
35
vi.)
At 28 days, the RCPT values were ranged from 3581 to 4549 Coulombs,
showing that the chloride permeability was in moderate to high. Besides, the
decrease in the charge with the increase of the age of concrete shows that the
pore structure of the POS concrete improved due to the continual process of
hydration of cement products.
vii.)
Proper curing is required for POS concrete to achieve a good durability
especially at the later ages. Therefore, for the POS concrete, minimum
duration of moist curing should be carried out for at least 7 days.
Table 2.6:
Curing
designation
Curing Regimes [35]
Temperature &
Type of curing
Curing method
relative
humidity
Curing
duration
Covered with
CS1
Site-1
plastic sheet for
Temp = 28 ±5oc
Until the age
three additional
RH = 68 – 91%
of testing
days
Covered with wet
burlap for six
CS2
Site-2
additional days &
water spray three
times a time
CL
CC
Laboratory
Unprotected (no
Temp = 25±3oc
(air-dry)
curing)
RH = 74 - 88%
Laboratory
(full water)
Temp = 23±2oc
Kept in water tank
RH = 100%
36
Table 2.7:
Time to Corrosion Initiation[35]
Time, years
Curing
Concrete cover
regimes
25 mm
50 mm
75 mm
100 mm
CS1
0.2
0.7
2.4
4.2
CS2
0.3
1.9
4.4
7.6
CL
0.2
0.7
2.2
3.9
CC
0.3
1.6
3.9
7.0
Figure 2.11: Volume of Permeable Voids of POS Concrete Under Different
Conditions[35]
37
Figure 2.12: Sorptivity of POS Concrete under Different Curing Conditions [35]
Figure 2.13: Water Permeability of POS Concrete under Different Curing
Conditions [35]
38
Figure 2.14: Chloride Profile in POS Concrete under Different Curing Conditions
[35]
Figure 2.15: Variation of RCPT Values for POS Concrete under Different Curing
Conditions [35]
39
2.11.3 Study 3
A group of researchers conducted a study on the effect of curing conditions
on the properties of POS concrete [36]. In this study, effect 6 types of curing
conditions on the pulse velocity and compressive strength of POS concrete were
studied. Table 2.8 showed the curing conditions of both type of concretes. Figure
2.16 and Figure 2.17 shows the variation of the pulse velocity of both type concretes.
Figure 2.18 and Figure 2.19 showed the development of compressive strength of
both types of concrete. The results obtained from the investigation were shown
below:
i.)
The pulse velocity of the POS concrete was about 25% lower than the
crushed stone concrete.
ii.)
The compressive strength of POS concrete was about 52% lower than the
crushed stone concrete.
iii.)
The compressive strength of the POS concrete satisfies the minimum
required strength as structural lightweight concrete.
iv.)
The method and curing period have significant effects on engineering
properties for both types of concrete. The strength development of the POS
concrete was delay at the early stages due to the early drying and the
present of organic POS aggregate.
v.)
The strength of the concrete is dependent to some extent of the aggregate
strength.
vi.)
The increment rate of strength is higher in the crushed stone compared to
POS concrete.
40
Table 2.8:
Curing Conditions for Both POS Concrete and Controlled Concrete
[36].
No.
1
2
3
4
5
6
Duration of curing with place (day)
Curing
Curing
description
symbol
Mold
Water
Plastic
Room
Full water
FW
1
364
0
0
PW-1
1
6
0
358
PW-2
1
27
0
337
FP-1
1
6
364
0
PP-1
1
6
358
0
PP-2
1
27
337
0
Partial
water-1
Partial
water-2
Full
plastic
Partial
plastic
Partial
plastic 2
Figure 2.16: Variation of Ultrasonic Pulse Velocity with Curing Age of POS
Concrete under Six Types of Curing Environment [36].
41
Figure 2.17: Variation of Ultrasonic Pulse Velocity with Curing Age of
Controlled Concrete under Six Types of Curing Environment [36]
Figure 2.18: Relationship between the Compressive Strength and the Curing Age
of the POS concrete under 6 types of Curing Conditions [36]
42
Figure 2.19: Relationship between the Compressive Strength and the Curing Age
of the Controlled Concrete under 6 types of Curing Conditions [36]
2.11.4 Study 4
A group of researchers also conducted study on long term strength of
concrete with palm oil shell as coarse aggregate [37]. In this study, long term
investigation up to 365 days on compressive strength of POS concrete in different
environmental conditions was conducted. Besides that, a comparative study also
being carried out by using controlled concrete with crushed stone as coarse concrete.
From this study, the compressive strength of POS concrete range from 20 to 24
N/mm2 for 28 days in different types of curing includes the field and laboratory.
Table 2.9 showed the curing condition for both type of concrete. Figure 2.20 and
Figure 2.21 showed the development of compressive strength of POS concrete and
controlled concrete in different curing conditions. The observations are shown as
follows:
i.)
The compressive strength of the POS concrete was in the range of 20.1 to 24
N/mm2 depend on the type of curing.
43
ii.)
The long term behavior of POS concrete was very similar to the controlled
concrete in generally. Hence, there was no retrogression of compressive
strength due to any of the curing conditions.
iii.)
Hence, the use of POS concrete as structural lightweight concrete is
recommended.
Table 2.9:
Curing Conditions for both POS Concrete and Controlled Concrete
[37]
Duration of curing with place (day)
Number
Curing
symbol
Mold
Water
Kept in room
temperature
1
W-1
1
6
358
2
W-2
1
27
337
3
W-3
1
364
-
4
P-1
1
6
5
P-2
1
27
6
P-3
1
-
358 (with plastic
wrapper)
337 (with plastic
wrapper)
364 (with plastic
wrapper)
44
Figure 2.20: Development of Compressive Strength of POS Concrete with
Different Curing Conditions [37]
Figure 2.21: Development of Compressive Strength of Controlled Concrete with
Different Curing Conditions [37]
45
CHAPTER III
METHODOLOGY
3.1
Introduction
This research program is designed to study the performance of concrete with
uncrushed palm oil shell as coarse aggregate. In this study, a total of 54 concrete
cubes and 54 concrete prisms were cast and tested. Besides, a total of 4 underreinforced concrete beams were fabricated and tested. A controlled beam and
concrete cubes and prisms without any palm oil shell replacement were used for the
comparison purposes.
In this study, for the palm oil shell concrete cube, the observations will be
more on the workability, the ultrasonic pulse velocity, air-dry density, the
compressive strength, and the mode of failure. For the palm oil shell concrete prism,
the test includes the bending test. For the palm oil shell concrete beams, the
observation will be more on the deflection, strain, type of failures, the crack
behavior, and the ultimate load carrying capacity. Comparisons will lead to the
effect of the palm oil shell as coarse aggregate on the performance of the concrete.
46
3.2
Experimental Program
In this study, a total of 54 concrete cubes of dimensions 150 x 150 x 150 mm,
54 concrete prisms of dimensions 100 x 100 x 500 mm, and a total of 4 concrete
beams with the dimensions of 150 x 125 x 1600 mm were cast and tested. The
concrete was design having a compressive strength of 30 MPa at the age of 28 days
with water-cement ratio of 0.52. The concrete mix was designed based to the DOE
method. Table 3.1 shows the mix proportion of the concrete with w/c of 0.52.
Besides, additional concrete cubes with 50% and full replacement of coarse
aggregate with POS were cast with water-cement ratio of 0.45 and 0.40, respectively,
and tested at the age of 7 days and 28 days. Table 3.2 shows the mix proportions of
cube specimens with w/c of 0.45 and 0.40, respectively.
For concrete cubes, a total of 6 sets of concrete cubes were cast and tested.
Each set of the cubes have different replacement percentage of coarse aggregate
with the POS. The replacement percentages were 50% and full replacement of
coarse aggregates with the POS. The replacement was done by using volume
method. Besides, additional samples with 10% of the cement content by weight
were replaced by fly ash and mixed with the POS were cast. Each sample set have a
quantity of 9 units. These cubes were tested at the age of 3, 7 and 28 days. Tests
include the ultrasonic pulse velocity test, dry-density, and the compressive strength
test. Table 3.3 shows the details of the cubes. Same procedures for the concrete
prisms were done. Table 3.4 shows the details of the prisms.
For concrete beams, a total of 4 under-reinforced concrete beams with the
dimensions of 125 x 150 x 1600 mm were fabricated and tested. One of the beams
was control beam; the other one was control beam but replaced with 10% of fly ash.
The other two beams were cast by replacing the coarse aggregate with POS with
different percentage. The percentage replacement were 50% and full replacement of
coarse aggregate. The replacement of coarse aggregate was done by volume in
47
percentage. Each beam was fabricated with high tensile strength of 10 mm diameter
reinforcement bar. Each concrete beams were tested to failure at the age of 28 days
by using four-point load test to determine its flexural strength and behaviour.
The control beam was designed according to the British Standard, BS
8110:1997-Structural use of concrete: code of practice for design and construction
[38]. The other POS concrete beams were design by referring the control beam as to
make comparison between the samples and the control beam. Table 3.5 shows the
details of the concrete beams.
Table 3.1:
Mix Proportion of Concrete with Water-Cement Ratio 0.52
Quantity ( kg/m3)
Description
Concrete without fly ash
Free water content
210
Cement content
405
Fine aggregate content
700
Coarse aggregate content
1090
Concrete with fly ash
Free water content
210
Cement content
364
Fly ash content
40
Fine aggregate content
700
Coarse aggregate content
1090
48
Mix Proportion of Concrete with w/c 0.45 and 0.4 respectively
Table 3.2:
Quantity ( kg/m3)
Description
CB0.5POS with w/c 0.45
Free water content
182
Cement content
405
Fine aggregate content
700
Coarse aggregate content
1090
CB1.0POS with w/c 0.40
Free water content
162
Cement content
405
Fine aggregate content
700
Coarse aggregate content
1090
Table 3.3:
Sample Identification
Sample Specimen for Compression Test
Quantity
POS (%)
Fly Ash (%)
CB 0.0 POS
9
0
0
CB 0.5 POS
9
50
0
CB 1.0 POS
9
100
0
CB 0.0 POSFA
9
0
10
CB 0.5 POSFA
9
50
10
CB 1.0 POSFA
9
100
10
Cubes (150x150x150 mm)
Notation:
CB – Cube, POS – Palm Oil Shell, FA – Fly Ash,
Numerical digit – Percentage Replacement of POS
49
Table 3.4:
Sample Identification
Sample Specimen for Bending Test
Quantity
POS (%)
Fly Ash (%)
PS 0.0 POS
9
0
0
PS 0.5 POS
9
50
0
PS 1.0 POS
9
100
0
PS 0.0 POSFA
9
0
10
PS 0.5 POSFA
9
50
10
PS 1.0 POSFA
9
100
10
Prisms (100x100x500 mm)
Notation:
PS – Prism, POS – Palm Oil Shell, FA – Fly Ash,
Numerical digit – Percentage Replacement of POS
Table 3.5:
Beam Identification
Beam Specimen for Flexural Test
Steel reinforcement
POS replacement (%)
Fly ash (%)
BC0.0POS
2-T10
0
0
BC0.0POSFA
2-T10
0
10
BC0.5POS
2-T10
50
0
BC1.0POS
2-T10
100
0
Notation:
BC – Beam Concrete, POS – Palm Oil Shell, FA – Fly Ash,
Numerical digit – Percentage Replacement of POS
3.3
Sieve Analysis
Sieve analysis was conducted to determine the aggregates used for the
mixture to meet the specification. Sieve test was done on the fine aggregate, coarse
aggregate and POS aggregate. In this study, the fine aggregate was sieved to
determine its grading stated in British Standard, BS 882: 1992 – Specification for
Aggregates from Natural Sources for Concrete [39].
50
3.4
Design of Reinforced Concrete Beam
The control reinforced concrete beam was designed in accordance to the
British Standard, BS8110: Part 1: 1997 – Structural Use of Concrete: Code of
Practice for Design and Construction [38]. The other 3 beams were design similar to
the control beam for comparisons purpose. Due to some limitations on the
availability of the reinforced material, the size of the beams with dimensions of 125
x 150 x 1600 mm was chosen.
3.5
Laboratory Works
All laboratory works were carried out in Structures and Materials
Laboratory, Faculty of Civil Engineering, Universiti Teknologi Malaysia. The works
included the preparation of raw materials, concrete cubes and prisms, beams, and
testing of all the samples.
3.5.1 Materials of Concrete
Raw materials such as ordinary Portland cement, fly ash, coarse aggregate,
uncrushed palm oil shell (POS) and fine aggregate were required in the preparation
for the concrete mix. The concrete mix was designed to achieve a compressive
strength of Grade 30 according to the Design of Normal Concrete Mixes,
Department of Environment (DOE) Method [40].
The type of the cement used was Ordinary Portland Cement (OPC) with
Holcim brand as shown in Figure 3.1. The fly ash is shown in Figure 3.2. The coarse
51
aggregate used was uncrushed palm oil shell as shown in Figure 3.3. The river sand
was used in this study. Sieve analysis was conducted according to the British
Standard, BS 882: 1992 – Specification for Aggregates from Natural Sources for
Concrete [39] to determine the percentage of fine aggregates that passes through 600
μm size. Besides, the maximum size of coarse aggregate used in this study was 20
mm. Finally, both of these aggregates were dried through air dry method. Figure 3.4
shows the air-dry sand.
For the uncrushed POS aggregates, special treatments were carried out
during the preparation. Usually, there will be oil coating on the surface of POS.
Hence, POS aggregates were washed to clear the oil coating on the shell. Before the
mixing process, the POS was pre-soaked in portable water for 24 hours as shown in
Figure 3.5. After that, the shells were taken out and let it for air dry to achieve a
saturated surface dry condition as shown in Figure 3.6. Then, these saturated surface
dry POS were used in concrete mixing.
Trial mix was conducted before the actual mixing process to ensure that the
concrete will achieve the required compressive strength. In trial mix, a total of 3
cubes were cast to determine the compressive strength at the age of 7 days.
By calculating the volume of 9 unit cubes, approximately 0.031 m3 of
concrete mixture was required in casting. Extra 10% of concrete volume was added
for proper placing and testing. Besides, 9 concrete prisms were cast and used 0.045
m3 of concrete mixture. Additional 10% of concrete volume required for proper
placing. For the concrete beam, approximately 0.03 m3 of concrete mixture was
required in casting. Extra 25% of concrete was added for proper placing and testing.
Extra cubes were prepared with the beams to determine the compressive strength of
concrete at the day the beams is tested.
52
Figure 3.1:
Cement
Figure 3.2:
Fly Ash
Figure 3.3:
Uncrushed Palm Oil Shell
53
Figure 3.4:
Figure 3.5:
Air-Dry Sand
Pre-soaked of POS Aggregates in Water
54
Figure 3.6:
Air-Dry POS Aggregates
3.5.2 Reinforcements
In this study, reinforcement steel bar of 10 mm diameter and shear link of 6
mm diameter were used in fabricating the beams. The length of the steel bars and
the shear links were cut into the required length. The cutting process was done by
using the electrical cutter whereas the bent process was done by using electrical
bender machine. The reinforcement bars and the shear links were tied together by
using wire.
Strain gauge was use and fixed at the centre of the reinforcement bar.
Grinder was used to roughen the steel bars surface where the strain gauge is located
for proper bonding. In preventing the short circuit due to the water from concrete
mixing, the strain gauge was covered with water proofing gel namely N1 glue and
left for 24 hours which shown in Figure 3.7. Lastly, the strain gauge was covered
with bitumen film to protect it from aggregate dropping impact during the concrete
pouring as shown in Figure 3.8. The in-placed strain gauge was tested by using
ammeter to ensure it will gives reading within 120 -125 ampere.
55
After all the preparation works have been done, the reinforcements were tied
with the 25 mm spacers into the formwork as shown in Figure 3.9. The whole
reinforcement cage is shown in Figure 3.10. The reinforcement cage in formwork is
shown in Figure 3.11. After that, concrete was poured and cast into the formwork.
Figure 3.7:
Figure 3.8:
Strain Gauge with N1 Glue
Bitumen Film on the Strain Gauge
Figure 3.9:
25 mm Spacer
56
Figure 3.10: Reinforcement Cage
3.5.3 Formwork
The standard steel mould for cubes has been provided; the only preparation
is a layer of oil applies on the surface of the formwork one day before casting the
cube. For the beams, the type of formwork used was made of plywood. Oil coating
were applied on the formwork surface for easier in demoulding the concrete from
formwork after 7 days. Figure 3.11 show the reinforcement cage in the formwork.
Figure 3.11: Reinforcement Bar in Formwork
57
3.5.4 Concrete Mixing
Before the concrete mixing, the quantities of each constituent were prepared
by using the weighing scale. All of the specimens were cast by using mechanical
pan mixer. The steps in concrete mixing are as follows:
i.)
The coarse aggregates were poured into the pan mixer followed by the fine
aggregates.
ii.)
The cement was poured into the pan mixer.
iii.)
Let the mixture of fine aggregates, coarse aggregate and cement thoroughly
mixed to obtained uniform mixture for about 5 minutes.
iv.)
Water was added slowly to the mixture.
v.)
Lastly, the mixture was mixed about 10 minutes in order to obtain uniform
mixture.
After the mixing process, some of the amount of fresh concrete was used for
workability testing. The others were placed into the formworks and used for the
making of the samples.
3.5.5 Placing Fresh Concrete
After conducting the workability test, the fresh concrete was place into the
formwork. The distance of the placement must be as low as possible to avoid the
segregation. For concrete cubes and prisms, the vibration of concrete was done by
using the vibrating table. For the concrete beams, the vibration was done by using
vibrating poker. The surface of the concrete was levelled to produce a smooth
surface as shown in Figure 3.12.
58
Figure 3.12: Finishing Surface of Concrete Cubes
3.5.6 Curing
After placing the fresh concrete, plastic film was put on it to reduce the
evaporation of water from the concrete. After 24 hours, the concrete cubes were
demould and cured in the water tank. For the concrete beams, the curing was done
by putting wet gunny covering on it as shown in Figure 3.13.
Figure 3.13: Curing of Concrete Beams
59
3.5.7 Installation of Demec Disc
After the proper curing, the process of patching mortar to the pores on the
concrete surface was done to get a smooth surface. White paint was applied on the
surface to enable the cracks can be detected easily during the flexural test. Demec
disc were installed on the surface of beam by bonding it with epoxy as shown in
Figure 3.14. Demec disc with spacing of 150 mm were used to determine the
concrete strain during the test.
Demec Disc
Figure 3.14: Demec Disc on Concrete Beam Surface
3.6
Laboratory Test
A series of test were conduct on the performance of concrete with palm oil
shell as coarse aggregate. Tests conducted include sieve analysis, compressive test
on POS aggregates, trial mix, slump test, UPV test, determination of apparent drydensity, cube test, and flexural test.
60
3.6.1 Sieve Analysis
Sieve analysis was conducted on the POS aggregates, the river sand and the
coarse aggregates. Coarse aggregate with 20 mm size was used in this study.
3.6.2 Compression Test on POS Aggregates
Compressive strength test was done on the POS aggregates and the gravel
aggregates to determine the peak load that the aggregates can carry. This test was
done but not according to any standard.
3.6.3 Trial Mix
Trial mix was conducted to determine the required compressive strength of
the concrete will be achieved at the age of 28 days. The mixing was done by hand
since it has only a small quantity, i.e. for 3 cubes.
3.6.4 Slump Test
Slump test was conducted on the fresh concrete to determine its workability.
The fresh concrete was placed into the slump cone with 300 mm height and
compacted in three layers. Each layer was compacted with 25 strokes by using steel
rod. After that, the frustum was lifted up and the displacement of the original top
surface was measured as the slump and shown in Figure 3.15.
61
Slump
Figure 3.15: Slump Test
3.6.5 Apparent Air-Dry Density of Concrete Cube
The air-dry density of concrete cube was conducted at the age of 3, 7 and 28
days. In this test, the weights of the samples were determined and divided by its
volume to get the density.
3.6.6 Ultrasonic Pulse Velocity (UPV) Test
UPV test was conducted on the concrete cube to determine the time taken for
the pulse to pass through the concrete. Before the test, the calibration was carried
out by using a reference bar having a known pulse transmit time value. The surface
of the transmitter was applied with grease to enhance the surface contact with the
concrete. The transmitter was placed at the centre cube position and the receiver at
the opposite side of the cube. The time taken for the ultrasonic pulse to travel from
62
the transmitter through the length of the cube to the receiver was recorded. From
these values, the global average value of pulse velocity of the cubes was determined.
3.6.7 Cube Test
Compressive strength test was conducted on the concrete cubes at the age of
3, 7 and 28 days. The cubes must be free from the cracks, chipped surface and other
defects that can give inaccurate results. All specimens were tested at the loading rate
of 6.8 kN/sec by using compressive machine. Figure 3.16 shows the compressive
strength test on concrete cubes.
Figure 3.16: Compressive Strength Test of Concrete Cube
3.6.8 Flexural Strength Test on Prisms
Flexural strength test was done on the concrete prisms according to British
Standard, BS 1881-118:1983-Method for the Determination of Flexural Strength
[41]. The flexural strength test was done on specimens at the age of 3, 7 and 28 days.
63
The test was done by using four point load test. The load causing the break of prism
was recorded and converted to flexural strength by using formula:
=
×
× 22
Where,
f is the breaking load in N
d1 and d2 are the lateral dimensions of the cross-section in mm
l is the distance between the supporting rollers in mm
3.6.9 Flexural Strength Test on Concrete Beams
Flexural strength test was conducted on the beams at the age of 28 days.
Magnus frame was used during the flexural strength test. Figure 3.17 shows the
Magnus frame.
During this test, hydraulic jack component was loaded at the mid span of the
beam. Steel spreader was put at the end of the jack to produce two point loads with
equal distance from the mid span of the beam. Besides, an electronic component
load cell was placed at the end of the jack to measure the applied load on the beam.
Linear Variable Differential Transducers (LVDT) was used in measuring the
deflection of the beam when the load was applied. A total of three LVDT were used
in this test and placed at the bottom part mid span of the beam. After that, all the
components including the strain gauge, load cell and transducers were connected to
data logger to obtain the experimental data. Figure 3.18 shows the set up of the
flexural test.
64
After preparation, the load was applied to the beam with certain increment
until failure. Demec disc was used to record the data of strain distribution of
concrete through measuring the displacement between the demec disc.
Figure 3.17: Flexural Test and Component Equipments
Figure 3.18: Arrangement of Components on Concrete Beam
65
CHAPTER IV
RESULTS AND ANALYSIS
4.1
Introduction
All the data obtained from the experiment were analysed in this chapter. The
data obtained include the cube strength test, UPV test, bending prism test and fourpoint flexural test of beams.
In this analysis, the reinforced concrete beams with the palm oil shell as
coarse aggregate replacement were compared with the conventional reinforced
concrete beam. In order to make the results more clearly, all the data were tabulated
and presented in tables and graphs. The data from the workability of fresh concrete,
compressive test and UPV test of the cubes, bending test of the prisms, compressive
test on the conventional aggregate and palm oil shells were compared in certain age
of the concrete. Lastly, the four beams were compared in terms of the ultimate
strength, deflection, strain of concrete and the reinforcement bar, the pattern of the
cracking, the bonding characteristic between the concrete and steel bar, the changes
of the neutral axis and the mode of failure.
66
4.2
Sieve Analysis
Table 4.1 shows the result of sieve analysis for fine aggregate which were
used in the concrete mixture. From the analysis of the result, the fine aggregate was
categorized in the medium class. This was because the percentage of the fine
aggregates passing through the 600 μm sieve was 40.36%. Based on the British
Standard, BS 882: 1992 – Specification for Aggregates from Natural Sources for
Concrete [39], this value was located within the range of the medium grading limit.
Table 4.2 shows the sieve analysis result of conventional coarse aggregate whereas
Table 4.3 shows the sieve results of POS aggregates. Figure 4.1 show the graph of
sieve analysis for fine aggregates. From the graph, the percentage passing of fine
aggregate is within the upper limit and lower limit which were categorized as
medium class.
Figure 4.2 shows the grading of POS and conventional coarse
aggregate. Figure 4.3 shows the sieve results of fine aggregates, conventional coarse
aggregates and POS aggregates.
Table 4.1:
Sieve Analysis Result of Fine Aggregates
Medium
Size Sieve
Retained
Passing
Percentage
(mm)
Weight (g)
Weight (g)
Passing (%)
5.0
0.2
499.8
99.96
-
2.36
26.3
473.5
94.7
65-100
1.18
121.5
352
70.4
45-100
0.60
150.2
201.8
40.36
25-80
0.30
113.2
88.6
17.72
5-48
0.15
68.9
19.7
3.94
-
pan
19.7
-
-
-
Total
500
-
-
-
Grading Limit
(%)
67
Table 4.2:
Sieve Analysis Result of Conventional Coarse Aggregates
Size Sieve
Retained Weight
Passing Weight
Percentage Passing
(mm)
(g)
(g)
(%)
28.0
0
2000.0
100
19.0
355.0
1645.0
82.25
13.2
790.0
855.0
42.75
9.5
330.0
525.0
26.25
4.0
430.0
95.0
4.75
2.8
20.0
75.0
3.75
pan
75.0
-
-
Total
2000
-
-
Table 4.3:
Sieve Analysis Result of POS Aggregates
Size Sieve
Retained Weight
Passing Weight
Percentage Passing
(mm)
(g)
(g)
(%)
28.0
0
2000.0
100
19.0
55.0
1945.0
97.25
13.2
1080.0
865.0
43.25
9.5
805.0
60.0
3.0
4.0
60.0
0
0
2.8
0
0
0
pan
0
-
-
Total
2000
-
-
68
120
Percentage Passing (%)
100
80
60
sample
lower limit
40
upper limit
20
0
0.0
1.0
2.0
3.0
4.0
5.0
6.0
Sieve Size (mm)
Figure 4.1:
Sieve Analysis for Fine Aggregate
120
Percentage Passing (%)
100
80
POS Aggregates
60
Conventional Coarse
Aggregates
M(LL)
40
M(UL)
20
0
1
Figure 4.2:
10
Sieve Size (mm)
100
Grading for POS and Conventional Coarse Aggregate
69
120
Percentage Passing (%)
100
80
POS Aggregates
60
Conventional Coarse
Aggregates
40
Fine Aggregates
20
0
0.1
1
10
100
Sieve Size (mm)
Figure 4.3:
Sieve Analysis for Fine Aggregates, Coarse Aggregates and POS
Aggregates
4.3
Compressive Strength Test of POS Aggregates and Conventional Coarse
Aggregates
Compressive strength test was done on the POS aggregates and conventional
coarse aggregates. The data obtained were tabulated in Table 4.4. From the results,
it can be seen that the POS aggregates have a lower load carrying capacity compared
with the conventional coarse aggregates. This may due to the higher porosity inside
the POS compared with the conventional coarse aggregates. Figure 4.4 and 4.5
shows the failure mode of the POS aggregates and conventional coarse aggregates,
respectively.
70
Table 4.4:
Peak Load Carried by POS and Conventional Coarse Aggregates
Peak Load (kN)
No.
Uncrushed POS Aggregates
Conventional Coarse Aggregates
1
0.9
2.9
2
1.6
3.2
3
2.2
3.3
4
1.5
3.0
5
1.4
2.8
6
1.2
3.5
7
1.1
3.1
8
0.7
3.8
9
2.0
3.4
10
1.3
2.9
Average
1.4
3.2
Figure 4.4:
Failure Mode of POS Aggregates
71
Figure 4.5:
4.4
Failure Mode of Conventional Coarse Aggregates
Slump Test
Slump tests were conducted on the fresh concrete to determine the
workability of concrete. The slump of the concrete was determined by measuring
the displacement of the top surface concrete from the original surface. As the
percentage replacement of the POS increases, the workability of the concrete
increase. This was due to the shape and the surface texture of the POS. The round
and smooth surface of the POS decrease the friction between the aggregates and
hence increase the aggregate movement compared to conventional aggregate which
have rough and irregular shape. The results were tabulated in Table 4.5 and shown
in Figure 4.6.
Table 4.5:
Samples
Workability of Fresh Concrete
Slump (mm)
CB0.0POS
30
CB0.0POSFA
30
CB0.5POS
75
CB0.5POSFA
70
CB1.0POS
115
CB1.0POSFA
110
72
140
120
Slump (mm)
100
80
60
40
20
0
CB0.0POS
CB0.0POSFA
CB0.5POS
CB0.5POSFA
CB1.0POS
CB1.0POSFA
Sample
Figure 4.6:
4.5
Workability of Fresh Concrete
Apparent Density of Concrete Cube
From the determination of density of concrete cube, the density of POS
concrete cube have a lower density compared to the normal weight concrete due to
the lightweight of the POS aggregates. The densities of all the concrete cubes with
w/c of 0.52 were tabulated in Table 4.6. The density of concrete cube of CB0.5POS
and CB1.0POS with w/c of 0.45 and 0.40, respectively are shown in Table 4.7. The
weight savings of the POS concrete was compared with the normal weight concrete
at the age of 28 days as shown in Table 4.8. The benefit of reducing weight can
reduce the dead load of structure. Besides, it can reduce the influence of the
catastrophic earthquake force and inertia force that influenced the structure since
these forces were proportional to the weight of structure [4].
73
Table 4.6:
Sample
Ages
(days)
3
CB0.0POS
7
28
3
CB0.0POSFA
7
28
Density of Samples with w/c 0.52
No’s
Weight (kg)
Density
(kg/m3)
1
8.155
2416.3
2
8.23
2438.5
3
8.15
2414.8
1
8.085
2395.4
2
8.075
2392.6
3
8.150
2414.7
1
8.240
2441.5
2
8.235
2440.0
3
8.195
2442.2
1
8.242
2442.1
2
8.263
2448.3
3
8.163
2418.7
1
8.214
2433.8
2
8.287
2455.4
3
8.333
2469.0
1
8.265
2448.9
2
8.292
2456.9
3
8.253
2445.3
Average
density
(kg/m3)
2423
2400
2441
2436
2452
2450
74
Table 4.6:
Sample
Ages
(days)
3
CB0.5POS
7
28
3
CB0.5POSFA
7
28
(Continues)
Weight
Density
(kg)
(kg/m3)
1
7.370
2183.7
2
7.470
2213.3
3
7.479
2216.0
1
7.433
2202.4
2
7.195
2131.9
3
7.297
2162.1
1
7.448
2206.7
2
7.449
2207.1
3
7.490
2219.3
1
7.450
2207.4
2
7.289
2159.7
3
7.423
2199.4
1
7.483
2217.0
2
7.382
2187.1
3
7.431
2201.8
1
7.363
2181.5
2
7.404
2193.6
3
7.421
2198.8
No’s
Average
density
(kg/m3)
2204
2165
2211
2189
2202
2191
75
Table 4.6:
Sample
Ages
(days)
3
CB1.0POS
7
28
3
CB1.0POSFA
7
28
(Continues)
Weight
Density
(kg)
(kg/m3)
1
6.342
1879.1
2
6.194
1835.3
3
6.253
1852.7
1
6.180
1831.1
2
6.260
1854.8
3
6.290
1863.7
1
6.549
1940.3
2
6.458
1933.3
3
6.435
1926.5
1
6.066
1797.3
2
6.152
1822.8
3
6.107
1809.5
1
6.110
1810.4
2
6.070
1798.5
3
6.170
1828.1
1
6.474
1918.2
2
6.527
1933.9
3
6.555
1919.2
No’s
Average
density
(kg/m3)
1856
1850
1933
1810
1812
1924
76
Density of Concrete Cube with w/c of 0.45 and 0.40
Table 4.7:
Sample
Ages (days)
No’s
Weight (kg)
7.495
2220.7
2
7.524
2229.3
CB0.5POS
3
7.495
2220.7
w/c:0.45
1
7.537
2233.2
2
7.387
2188.7
3
7.547
2236.1
1
6.220
1842.8
2
6.183
1832.0
CB1.0POS
3
6.198
1836.4
w/c:0.40
1
6.165
1826.7
2
6.265
1856.3
3
6.185
1832.6
28
7
28
Table 4.8:
density
(kg/m3)
1
7
Average
Density
(kg/m3)
2223
2219
1837
1838
Density of Concrete Cube at Ages of 28 days
Samples
Density (kg/m3)
Weight Savings (%)
CB 0.0POS
2441
-
CB0.0POSFA
2450
-
CB0.5POS
2211
9.26
CB0.5POSFA
2191
10.06
CB1.0POS
1933
20.65
CB1.0POSFA
1924
21.04
77
4.6
Ultrasonic Pulse Velocity Test (UPV Test)
This test was conducted to determine the indirect compressive strength of the
concrete cube. This test was conducted according to British Standard, BS 1881: Part
203: 1983 – Recommendations for Measurement of Velocity of Ultrasonic Pulses in
Concrete [42].
The UPV Test results were summarized in Table 4.9. In order to make the
comparisons more clearly, the data were plotted in graph as shown in Figure 4.7.
Table 4.9:
Results of UPV Test
Average velocity (km/s)
Ages ( Days)
Sample
3
7
28
CB0.0POS
4.27
4.37
4.63
CB0.0POSFA
4.19
4.49
4.66
CB0.5POS
3.99
4.19
4.31
CB0.5POSFA
3.94
4.10
4.20
CB1.0POS
3.23
3.30
3.71
CB1.0POSFA
2.99
3.24
3.51
78
60
50
Time (μs)
40
CB0.0POS
CB0.0POSFA
30
CB0.5POS
20
CB0.5POSFA
CB1.0POS
10
CB1.0POSFA
0
3
7
28
Ages (Days)
Figure 4.7:
4.7
Comparisons of Time Taken for Specimens
Cube Test
To ensure the mix design meets the requirement in terms of the compressive
strength and the workability, trial mixes were conducted. The trial mix of concrete
with grade 30 and water cement ratio of 0.52 were carried out. The result showed
that the trial mix meets the design requirement in terms of the compressive strength
and the workability.
The results of the cube test for the trial mix and design were summarised in
Table 4.10. In order to make the comparisons more clearly and the trend
development of the compressive strength of concrete, graph in Figure 4.8 was
plotted. The strength development of the POS concrete was same as the control cube,
i.e. the compressive strength continues developed with ages as shown in Figure 4.8.
79
Since the compressive strength of the concrete cube CB0.5POS and
CB1.0POS with w/c of 0.52 didn’t meet the structural compressive strength
requirement i.e. 25 MPa, hence, additional concrete cubes CB0.5POS and
CB1.0POS with w/c of 0.45 and 0.40, respectively, were cast and tested. The
compressive strength of CB0.5POS and CB1.0POS were tabulated in Table 4.11.
Comparisons were made between the w/c of 0.52 and 0.45 together with 0.40 as
shown in Figure 4.9. The compressive strength of cube CB1.0POS was 18.1 MPa
which achieved the minimum compressive strength of structural lightweight
concrete which is 17 MPa according to ASTM C330 [43].
From the compressive strength test, it was found that the compressive
strength of concrete cube with POS replacement was lower than the control concrete
cube. As the percentage replacement of the POS increased, the compressive strength
of the concrete cube was decreased. This probably was due to the shape of the POS
aggregates. The circular shape of the POS causing weak interlocking bonding
between the aggregate and the cement paste.
The failure mode of the concrete cube was different at the age of testing. At
the early age of testing, the cube was fail in the cracking through the cement paste,
but at the later age of testing, the cubes fail mostly in coarse aggregate. This was
because the early strength of the concrete cube was governed by the strength of the
cement paste, but at the later age, the concrete strength was governed by the
aggregate strength. However, for the POS concrete cube, the failure mode at the age
of 28 days was observed break through the surface of the POS aggregates rather
than break through the POS aggregates. The failure modes of the samples are shown
in Figure 4.10, Figure 4.11 and Figure 4.12.
For control cube with 10% fly ash replacement, the strength at the early age
was lower than the control cube, but at the later age, the compressive strength was
almost the same with the control cube. This was because fly ash react with the
80
calcium hydroxide, Ca(OH)2 together with moisture content at the later age. At the
early age, the hydration of the cement produced little Ca(OH)2, but at the later age,
complete hydration of cement produce enough Ca(OH)2 for the fly ash to react with
the presence of moisture content. Fly ash reacts with Ca(OH)2 and with the presence
of moisture to produce more C-S-H gel and hence increase the compressive strength
of the cube. But for the cube with POS with 10% fly ash replacement, the strength
was lower than the cube with only POS replacement. The same results found by
other researchers. This may be due to the fact that fly ash prevented proper contact
between the POS surface and the cement matrix causing the lower bonding and
hence, reduce the compressive strength [3].
81
Table 4.10:
Compressive Strength of Concrete Cube for Trial Mix and Design
Fly Ash
Sample
Replacement
Compressive
Days
(%)
Strength
(MPa)
Average
Compressive
Strength
(MPa)
Ratio of
7/28 d
strength
30.9
Trial Mix
0
7
33.4
32.4
33.0
24.6
3
23.7
23.9
23.4
34.4
CB0.0POS
0
7
32.2
32.3
0.71
30.3
45.8
28
47.2
45.6
43.9
17.2
3
18.8
18.4
19.3
29.1
CB0.0POSFA
7
28.3
29.6
31.3
45.1
28
48.0
41.6
44.9
0.66
82
Table 4.10:
Fly Ash
Sample
Replacement
Days
(%)
(Continue)
Compressive
Average
Ratio of
Strength
Compressive
7/28 d
(MPa)
Strength (MPa)
strength
13.7
3
12.1
13.2
13.6
16.9
CB0.5POS
0
7
14.4
16.0
0.69
16.6
22.3
28
23.8
23.1
23.0
10.9
3
9.7
10.5
11.0
14.6
CB0.5POSFA
10
7
14.6
14.6
14.7
18.0
28
20.1
17.7
18.6
0.78
83
Table 4.10:
Fly Ash
Sample
Replacement
Days
(%)
(Continue)
Compressive
Average
Ratio of
Strength
Compressive
7/28 d
(MPa)
Strength (MPa)
strength
9.1
3
8.8
8.9
8.9
11.6
CB1.0POS
0
7
11.0
11.4
0.81
11.6
15.4
28
12.9
14.0
13.8
5.6
3
6.0
5.8
6.0
9.8
CB1.0POSFA
10
7
9.2
9.6
10.0
11.7
28
13.0
13.2
12.6
0.76
84
50.0
Compressive Strength (MPa)
45.0
CB0.0POS
40.0
CB0.0POSFA
35.0
30.0
CB0.5POS
25.0
CB0.5POSFA
20.0
15.0
CB1.0POS
10.0
CB1.0POSFA
5.0
0.0
0
7
14
21
28
35
Ages (Days)
Figure 4.8:
Table 4.11:
Development Compressive Strength of Concrete Cubes
Compressive Strength of CB0.5POS and CB1.0POS with w/c of 0.45
and 0.40 respectively.
Sample
w/c
Ages
Compressive
(days)
Strength (MPa)
Average
Ratio of
Compressive
7/28 d
Strength (MPa)
strength
21.1
7
19.4
20.9
22.2
CB0.5POS 0.45
0.73
29.9
28
28.0
28.7
28.3
15.2
7
15.1
15.1
15.2
CB1.0POS 0.40
0.84
17.2
28
19.1
17.9
18.1
85
Compressive Strength (MPa)
Figure 4.9:
Comparisons Compressive Strength with different w/c
35
30
25
20
CB0.5POS-w/c 0.52
15
CB0.5POS-w/c 0.45
10
CB1.0POS-w/c 0.52
5
CB1.0POS-w/c 0.4
0
7
28
Ages (Days)
7 days
28 days
Figure 4.10: Failure Mode of Control Cube at the age of 7 days (left) and age of
28 days (right)
86
7 days
28 days
Figure 4.11: Failure Mode of CB0.5POS at the age of 7 days (left) and age of 28
days (right)
7 days
28 days
Figure 4.12: Failure Mode of CB1.0POS at the age of 7 days (left) and age of 28
days (right)
87
4.8
Flexural Strength Test of Prisms
Flexural strength test or modulus of rupture test was done on concrete prisms
and the data are tabulated in Table 4.12. The comparison of the flexural strength is
shown in Figure 4.13. Flexural strength is the ability of the beam or slab to resist the
failure in bending. From the test, all the prisms showed typical flexural strength
development as shown in Figure 4.13. But as the replacement of the POS increase,
the flexural strength of the prism was decreased. This showed that the POS prisms
have low flexural strength in resisting the failure in bending stress compared to
control concrete. Same trend of results also obtained by other researchers [1].
The flexural strength of CP0.0POSFA which has fly ash replacement was
lower at the early age when compared with the CP0.0POS. The rate of development
of flexural strength of CP0.0POSFA begins to increase with time as shown in Figure
4.13. This happens because during the early stage, the cement reacts with water to
produce C-S-H gel and Ca(OH)2, but the quantity of Ca(OH)2 was low at the early
stage. At later ages, the quantity of Ca(OH)2 becomes higher and the fly ash react
with the Ca(OH)2 with moisture to produce more silica gel, hence the flexural
strength increase with time.
For control prisms, the flexural strength was about 16% of the compressive
strength. On the other hand, for the control prisms with fly ash, the flexural strength
was about 14.7% of the compressive strength. For the prism CP0.5POS and
CP0.5POSFA, the flexural strength is about 17.7% and 22% of the compressive
strength, respectively. For the prisms CP1.0POS and CP1.0POSFA, the flexural
strength was about 19% and 21%, respectively, of compressive strength. These
values are within the normal range of flexural strength of conventional concrete
which is 10 to 23% of its compressive strength [44].
88
The flexural strength of POS concrete prisms was low compared with the
control prisms due to the circular shape of the POS aggregates. The angular coarse
aggregate used in the control concrete prisms provide a good bonding with the
cement paste. The failure mode of control prisms was different with the POS
concrete prisms at the first crack. At the first crack load, the control prisms broke
into two parts whereas for the POS concrete prisms, they didn’t broke into two parts
but still bond together as shown in Figure 4.14. The reason the broken part of the
prisms still bond together was due to the fibres on the POS surface as shown in
Figure 4.15. The failure modes of the concrete prisms were different at certain age
of testing as shown in Figure 4.16, Figure 4.17 and Figure 4.18. At the early stage,
the prisms break through the cement paste, but at the later age, the prisms break into
the cement paste and the coarse aggregates. However, for POS concrete prisms, the
failure was through on the surface of the POS aggregates rather than break through
the POS aggregates. This may due to the circular shape of the POS aggregate and
weak bonding between the surface of the POS aggregates and the cement paste.
89
Table 4.12:
Samples
Ages
(days)
3
CP0.0POS
7
28
3
CP0.0POSFA
7
28
Flexural Strength of Concrete Prisms
No’s
Flexural Strength
Average Flexural Strength
(MPa)
(MPa)
1
4.1
2
4.3
3
4.1
1
5.5
2
6.1
3
6.0
1
7.8
2
7.1
3
7.2
1
3.0
2
4.0
3
3.1
1
4.2
2
4.3
3
3.8
1
6.6
2
6.5
3
6.6
4.1
5.9
7.4
3.3
4.1
6.5
90
(Continues)
Table 4.12:
Flexural
Samples
Ages (days)
No’s
Strength
(MPa)
3
CP0.5POS
7
28
3
CP0.5POSFA
7
28
1
2.0
2
1.7
3
1.8
1
2.4
2
3.0
3
2.7
1
4.0
2
4.2
3
4.0
1
1.6
2
1.8
3
1.4
1
2.6
2
2.7
3
2.3
1
4.5
2
3.7
3
4.1
Average
Flexural
Strength
(MPa)
1.8
2.7
4.1
1.6
2.6
4.1
91
Table 4.12:
(Continues)
Flexural
Samples
Ages (days)
No’s
Strength
(MPa)
3
CP1.0POS
7
28
3
CP1.0POSFA
7
28
1
1.8
2
2.0
3
1.4
1
1.6
2
2.2
3
2.5
1
2.7
2
2.6
3
2.8
1
1.5
2
1.7
3
1.8
1
2.1
2
2.0
3
2.1
1
2.8
2
2.7
3
2.7
Average
Flexural
Strength
(MPa)
1.7
2.1
2.7
1.6
2.0
2.7
92
8
FlexuralStrength(MPa)
7
6
CP0.0POS
5
CP0.0POSFA
4
CP0.5POS
3
CP0.5POSFA
2
CP1.0POS
CP1.0POSFA
1
0
0
7
14
Ages(Days)
21
28
35
Figure 4.13: Development of Flexural Strength of Concrete Prism
Control
POS
Figure 4.14: Failure Mode of Prism without POS aggregates (left) and Prism with
POS aggregates (right)
Figure 4.15: Fibres on the Surface of POS Aggregates
93
7 days
28 days
Figure 4.16: Failure Mode of Controlled Prism at age of 7 days (left) and at age of
28 days (right)
7 days
28 days
Figure 4.17: Failure Mode of CP0.5POS at age of 7 days (left) and at age of 28
days (right)
94
7 days
28 days
Figure 4.18: Failure Mode of CP1.0POS at age of 7 days (left) and at age of 28
days (right)
4.9
Flexural Strength Test on Beam
During the flexural strength test on beams, the results obtained were ultimate
load, deflection, steel and concrete strain distribution, the cracking pattern, change
of neutral axis and mode of failure. Control beam was used to compare with other
concrete beams.
4.9.1 Load-Deflection of Concrete Beams
From the load deflection results, the data obtained were the ultimate load and
the deflection of the beam at the ultimate load as shown in Table 4.13. Figure 4.19
shows the load-deflection or flexural behaviour of all the concrete beams tested.
From the analysis, all the concrete beams show a typical structural behaviour in
flexure.
95
Ultimate Loads, First Crack Load and Maximum Deflection at the
Table 4.13:
Ultimate Load.
First crack load
Ultimate load
Maximum deflection
(kN)
(kN)
(mm)
BC0.0POS
8.5
39.5
11.35
BC0.0POSFA
8.0
39.8
16.92
BC0.5POS
8.0
33.5
11.09
BC1.0POSFA
6.0
34.5
11.12
Beam
45
40
35
Load (kN)
30
BC0.0POS
25
BC0.0POSFA
20
BC0.5POS
15
BC1.0POS
10
5
0
0
5
10
15
Deflection (mm)
20
25
Figure 4.19: Flexural Behaviour of All Concrete Beams
For control beam BC0.0POS, the first crack was found in the middle of the
span where the location of maximum bending occurred. The first crack load was 8.5
kN and the displacement of the mid span was 1.22 mm. The concrete tension strain
and the bar strain at the first crack load was 599.5 x 10-6 and 415 x 10-6, respectively.
Before the first crack occurred, the slope of load-deflection was steep and linear.
But after the flexural crack was formed, the change in slope of the load-deflection
curve occurred and remains linear until the major crack. After the major cracks
96
occurred, the reinforcement bar begins to yield. As the load increased, more vertical
cracks were observed along the beam. The major cracks were observed when the
loads achieved 36.9 kN. The beam failed when the load achieved 39.5 kN and failed
in flexural-tension mode. The displacement of the beam at the ultimate load was
11.35 mm.
For control beam with fly ash, BC0.0POSFA, the first crack load was found
in the middle of the span at the load of 8.0 kN. The displacement of the beam at the
first crack load was 1.26 mm and the concrete tension strain and bar strain was
708.5 x 10-6 and 426 x 10-6, respectively. Before the first crack load, the slope of the
load-deflection was steep and linear until the first crack occurred. After the first
crack occurred, the slope of the load-deflection has changed but remains linear until
the major cracks occurred. The major cracks occurred at load of 36.0 kN. The
ultimate load of this beam was 39.8 kN and the displacement of the beam at ultimate
load was 16.92 mm. After the ultimate load occurred, the reinforcement bar begins
to yield. The ultimate load of the beam BC0.0POSFA was almost similar with the
control beam, BC0.0POS. This may be due to the class F fly ash with low reactivity.
For POS concrete beam, BC0.5POS, the first crack was found in the middle
part of the beam where the constant bending moment occurred. The first crack load
was found to be 8.0 kN. The displacement of the concrete beam at the first crack
load was 1.41 mm and the concrete tension strain and reinforcement bar strain was
305.2 x 10-6 and 430 x 10-6, respectively. As the loading increase, there were more
cracks occurred until the major cracks occurred. The slope of the load-deflection
before the first crack was steep and linear, but after the first crack, change occurred
on the slope of the load-deflection and still remains linear until the major cracks
occurred. The major cracks occurred at load of 32.0 kN. The ultimate load of the
beam was 33.5 kN and the displacement of the beam was 11.42 mm. After that, the
yielding of the bar begins and the beam failed in crushing of concrete cover. The
ultimate load of this beam was lower than the control concrete beam due to the
lower compressive strength of the concrete. The compressive strength of the
97
concrete cube before the beam was tested at age of 28 days was 28.7 MPa compared
to 42 MPa of control concrete cube.
For concrete beam with full POS replacement, BC1.0POS, the first crack
was found at the mid span of the beam where the constant bending moment occurred.
The first crack load was found at about 6.0 kN. The first crack load of this beam was
low compared with the other 3 beams due to the weak bonding of the surface of
POS aggregates and cement paste. Besides, flexural strength test on prisms also
indicate that the full replacement POS have a lower flexural strength compared with
other prisms which were not fully replaced by POS coarse aggregates. The
deflection at the first crack load was 0.98 mm and the concrete tension strain and the
bar strain was 272.5 x 10-6 and 263 x 10-6, respectively. Before the first crack
occurred, the slope of the load-deflection was steep and linear, but after the first
crack occurred, change in the slope was occurred but still remain linear until the
occurrence of major crack. The major crack occurred at the load of about 32.1 kN.
The ultimate load of the beam was 34.5 kN and the displacement at the ultimate load
was 11.12 mm. The ultimate load of BC1.0POS was almost the same as CB0.5POS.
This may be due to the fibre effect on the surface of the POS aggregates. The
ultimate load for BC1.0POS was lower than the control beam due to the low
compressive strength of the concrete. At the day of beam testing, the compressive
strength of the concrete cube was only 18.1 MPa. But according to ASTM C330, the
minimum compressive strength required for lightweight structural applications was
17.0 MPa [43]. Hence, the BC1.0POS can be used in lightweight structural
applications.
4.9.2 Bonding Behaviour
The concrete strain for control beam in tension part and the reinforcement
strain were plotted and shown in Figure 4.20. Figure 4.21, Figure 4.22 and Figure
4.23 show the concrete strain and bar strain for beam BC0.0POSFA, BC0.5POS and
98
BC1.0POS, respectively. All the graphs show a typical strain increase as the load
increase.
For beam BC0.0POS, the steel strain increased as the load increased until it
yielded at the load of about 36.9 kN. The steel strain is about 3083 με before it
yielded. The beam still can carry certain amount of load after the steel yielded
before it failed at 39.5 kN. The steel strain at failure was about 15763 με. At the
same time, the concrete strain at the bottom part of the beam also increased as the
load increased. From the graph, the value of concrete strain was lower compared
with the steel strain. The differences may due to the method of strain measurement.
The concrete strains were measured using demec disc while the steel strains were
measured using electrical strain gauge which provide higher accuracy compared
with the demec disc.
For beam BC0.0POSFA, the steel strain was increased before it yielded at
load of about 36.0 kN. Before it yielded, the recorded steel strain was about 3497 με.
The beam still can carry some load before it failed at 39.8 kN. At the point of failure,
the steel strain was about 12402 με. At the same time, the concrete strain increased
as the load increased. Since the difference of the concrete strain and the steel strain
was lower, this showed that the bonding between the steel and the concrete was
good.
For beam BC0.5POS, the steel strain before it yielded was 2960 με at load
level of about 32 kN. This beam still can carry certain amount of load before it
failed at 33.5 kN with steel strain of about 8944 με. While for beam BC1.0POS, the
steel strain before it yielded was 2976 με at the load of about 32.1 kN. This beam
still can carry extra load before it failed at load of about 34.5 kN with the recorded
steel strain of 23143 με. The bonding between the concrete and the steel was good
for both beams, BC0.5POS and BC1.0POS, since the difference between the
concrete strain and steel strain was small.
99
45
40
35
Load (kN)
30
25
Concrete Strain
20
Bar Strain
15
10
5
0
0
2000
4000
6000
8000
10000 12000 14000
Strain (X 10-6 )
Figure 4.20: Graph Load versus Strain for Beam BC0.0POS
40
35
Load (kN)
30
25
20
Concrete Strain
15
Bar Strain
10
5
0
0
2000 4000 6000 8000 10000 12000 14000 16000
Strain (X 10-6 )
Figure 4.21: Graph Load versus Strain for Beam BC0.0POSFA
100
35
30
Load (kN)
25
20
Concrete Strain
15
Bar Strain
10
5
0
0
2000
4000
6000
8000
Strain (X 10-6 )
Figure 4.22: Graph Load versus Strain for Beam BC0.5POS
40
35
Load (kN)
30
25
20
Concrete Strain
15
Bar Strain
10
5
0
0
2000 4000 6000 8000 10000 12000 14000
Strain (X 10-6 )
Figure 4.23: Graph Load versus Strain for Beam BC1.0POS
101
4.9.3 Concrete Strain Distribution
Figure 4.24 shows the strain distribution for concrete in compression with
the load for all the beams. From the graph, the strain of concrete increased as the
load increased. The strain for beam BC0.0POS was 861.1 με whereas for beam
BC0.5POS and BC1.0POS, the concrete strain was 981 με and 1384.3 με,
respectively. For beam BC0.0POSFA, the concrete strain cannot be obtained before
the failure due to the error in measurement method. The concrete was designed to
fail in 3500 με theoretically. However, all the specimens were failed before the
design value due to the difficulty in obtaining the data since all data were recorded
using the demec gauge manually.
35
30
Load (kN)
25
20
BC0.0POS
BC0.0POSFA
15
BC0.5POS
10
BC1.0POS
5
0
0
500
1000
1500
Concrete Strain (X 10-6 )
Figure 4.24: Load versus Concrete Strain
102
4.9.4 Cracking Behaviour
Cracks happened at the bottom part of the beam due to the beam weak in
tension which occurred at the bottom part of the beam. The crack patterns played
important role in reinforced concrete structure. The characteristic of cracks on the
beam were recorded and shown in Table 4.14 and Table 4.15. Besides, the cracking
patterns of all the beams are shown in Figure 4.25.
Table 4.14:
Characteristic of Cracks
Maximum Crack
Average Crack
Depth (mm)
Depth (mm)
BC0.0POS
120
102.5
10
BC0.0POSFA
125
101.8
11
BC0.5POS
110
78.0
15
BC1.0POS
150
71.5
23
Beam
Table 4.15:
Total No of Cracks
Cracks Spacing Pattern for All Beams
NOS of Cracks per Spacing Range (mm)
Average
Crack
Beam
0-320
321-640
641-960
961-1280
1281-1600
Spacing
( mm)
BC0.0POS
0
4
5
4
1
96.0
BC0.0POSFA
1
5
2
3
1
104.5
BC0.5POS
1
6
4
3
1
76.8
BC1.0POS
1
7
5
9
2
49.8
103
For control concrete beam, the first crack started when the load applied was
about 8.5 kN. But for the beam BC0.0POSFA, BC0.5POS and BC01.0POS, the first
crack load was about 8.0 kN, 8.0 kN and 6.0 kN, respectively. The first crack load
for beam BC0.0POSFA, BC0.5POS and BC01.0POS was lower compared with the
control beam probably due to the weak bonding between the aggregates and the
cement paste. Same results were obtained through the flexural strength test of
prisms which indicated that the control prisms having higher flexural strength
compared with the other prisms specimens.
All of the vertical cracks were formed at the bottom of the beam. When the
applied load increased, the vertical cracks were gradually formed towards the upper
part of the beam. Major cracks were formed after certain load applied. The vertical
cracks widened progressively and propagated upwards. For control beam, the major
cracks formed at the load of about 36.9 kN. For beam BC0.0POSFA, BC0.5POS
and BC01.0POS, the major cracks were formed at load about 36.0 kN, 32.0 kN and
32.1 kN, respectively.
The maximum crack depth was on beam BC1.0POS due the weak bonding
of the aggregates compared with the control beam. For beam BC0.5POS, the
maximum crack depth was about 110 mm due to the beam failed in concrete
crushing at the upper part of the beam. For controlled beam and BC0.0POSFA, the
maximum crack depth was almost the same.
All beams have a combination of minor cracks and major cracks along the
beam. Besides, no cracks were found near the support location of all the beams and
this indicated that the beams were failed in bending-flexural mode. Beam
BC1.0POS has more vertical cracks compared with the control beam and beam
BC0.0POSFA. This may be due to the weak bonding between the aggregates and
the cement paste. Besides, there were no cracks along the reinforcement bar at the
104
bottom part of beam and this indicated that the bonding between the reinforcement
bar and the concrete was good.
BC1.0POS
BC0.5POS
BC0.0POSFA
BC0.0POS
Figure 4.25: Cracking Patterns for All Beam Specimens
4.9.5 Neutral Axis
The location of the neutral axis was shifted upward to the compression zone
of the beam as the load applied increased. Figure 4.26, 4.27, 4.28 and 4.29 shows
the location of the neutral axis as the load increased for beam BC0.0POS,
BC0.0POSFA, BC0.5POS and BC1.0POS, respectively. From the graph, all the
beam show a similar trend which the location of neutral axis shifted upward as the
load applied increased.
105
160
140
Beam Depth (mm)
120
100
4 kN
80
12 kN
60
20 kN
25 kN
40
20
0
-1000
0
1000
3000
2000
4000
Concrete Strain (x 10-6 )
Figure 4.26: Location of Neutral Axis for Beam BC0.0POS
160
140
Beam Depth (mm)
120
100
80
4 kN
60
12 kN
20 kN
40
20
0
-1000
-500
0
500
1000
1500
2000
2500
Concrete Strain (x 10-6 )
Figure 4.27: Location of Neutral Axis for Beam BC0.0POSFA
106
140
120
Beam Depth (mm)
100
80
6 kN
60
20 kN
25 kN
40
20
0
-1000
-500
0
500
1000
1500
2000
Concrete Strain (x 10-6 )
Figure 4.28: Location of Neutral Axis for Beam BC0.5POS
160
140
Beam Depth (mm)
120
100
4 kN
80
12 kN
60
20 kN
25 kN
40
20
0
-1500
-1000
-500
0
500
1000
1500
2000
2500
3000
Concrete Strain (x 10-6 )
Figure 4.29: Location of Neutral Axis for Beam BC1.0POS
107
4.9.6 Mode of Failure
Table 4.16 shows the type of failure for each beam specimen while Figure
4.30, 4.31, 4.32, 4.33 show the failure mode of beam specimens. Results from the
experiment show that all beams were failed in the flexural-tension mode. Before
all the beams failed in concrete compression, the reinforcement yielded as can be
expected for the under-reinforced concrete beam.
Table 4.16:
Beam
BC0.0POS
BC0.0POSFA
BC0.5POS
BC1.0POS
Mode of Failure for Concrete Beam Specimens
Failure Mode
Description
Flexural-
Reinforcement yielded before concrete failed in
Tension
compression
Flexural-
Reinforcement yielded before concrete failed in
Tension
compression
Flexural-
Reinforcement yielded before concrete failed in
Tension
compression
Flexural-
Reinforcement yielded before concrete failed in
Tension
compression
Figure 4.30: Failure Mode of Beam BC0.0POS
108
Figure 4.31: Failure Mode of Beam BC0.0POSFA
Figure 4.32: Failure Mode of Beam BC0.5POS
Figure 4.33: Failure Mode of Beam BC1.0POS
109
CHAPTER V
CONCLUSION AND RECOMMENDATION
5.1
Conclusion
After these series of laboratory tests, concrete with uncrushed pal oil shell as
coarse aggregates will have lower compressive strength and flexural strength
compared with the conventional concrete. The concrete beams with uncrushed palm
oil shell as aggregates exhibit same flexural behaviour as the conventional concrete
beam. However, the load carrying capacity was lower compared with the
conventional concrete beams. More extensive cracks were found for the POS
concrete beams compared with the conventional concrete beam. The number of
cracks provides sufficient warnings for the beam before failure occurred.
Based on the overall results, analysis and comparisons in terms of the
workability, compressive strength, flexural strength and flexural behaviour of the
concrete beams, the conclusions that can be drawn are as follows:
i.)
As the replacement of the POS increased, it increased the workability of the
fresh concrete due the spherical shape of the POS.
110
ii.)
The compressive strength and flexural strength of concrete cube and prisms
was decrease as the replacement of the POS increase.
iii.)
The density requirement for lightweight concrete is below 2000 kg/m3 [26],
which mean that only the full replacement of the POS concrete considered as
lightweight concrete.
iv.)
The minimum compressive strength for lightweight structural concrete is 17
MPa [43]. Hence, the full replacement of POS as aggregate can be used in
structural lightweight concrete which has compressive strength of 18.1 MPa.
v.)
The flexural behaviour of the concrete beams with POS replacement act
similar with the control concrete beams.
An overall conclusion can be stated that the concrete with uncrushed palm oil
shell as coarse aggregates can be used to reduce the member selfweight, which can
reduce the cost for bigger dimension for beam and column required, the quantity of
the reinforcement bar required and the bearing capacity of the foundations. Besides,
it can save the gravel aggregates usage and hence decrease the depletion rate of the
gravel aggregates.
5.2
Recommendation
There are several recommendations for further experimental works regarding
the usage of uncrushed POS as coarse aggregates in concrete in order to expand the
knowledge and findings in this area.
i.)
Additional of organic palm oil shell fibre in the concrete to determine the
effect on flexural strength.
ii.)
To study the creep and shrinkage of the uncrushed palm oil shell concrete.
iii.)
To study the sound and heat insulation of uncrushed POS concrete.
111
iv.)
To study the durability of POS concrete by using blended cement.
112
REFERENCES
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Teo, D. C. L., L.Y.F., The use of oil palm shell (OPS) as partial or full
replacement for aggregate in concretes.
[2]
[3]
[cited 2009; Available from: http:/econ.mpob.gov.my.
Basri, H.B., M.M.A., Zain M.F.M., Concrete using waste oil palm shells as
aggregates. Cement and concrete research, 1999. 29: p. 619-622.
[4]
Teo, D.C.L., M.M.A., Kurian V.J. , Structural concrete using oil palm shell
(OPS) as lightweight aggregate. Turkish journal of engineering and
environmental sciences, 2006. 30(4): p. 251-257.
[5]
Teo, D.C.L, M.M.A., Kurian J.V, Flexural behaviour of reinforced
lightweight concrete beams made with oil palm shell (OPS). Journal of
advanced concrete technology 2006. 4: p. No.3, 1-10.
[6]
Mannan, M.A., G.C., Concrete from an agricultural waste-oil palm shell
(OPS). Building and environment, 2004. 39(4): p. 441-448.
[7]
Teo, D.C.L, M.M.A., Kurian V.J, Ganapathy C., Lightweight concrete made
from oil palm shell (OPS): Structural bond and durability properties.
Building and environment 2007. 42: p. 2614-2621.
[8]
Rivera-Villareal, P., Ancient Structural Concrete in MesoAmerica, ACI
Spring Convention. Mar.21,1994.
[9]
Satish Chandra, L.B., Lightweight Aggregate Concrete, Science, Technology
and Applications.
[10]
e.v, L.B.-u.B.R.-P., Bauen mit N, Tagungsband zu Bimstagen 30/31. Mar.
1995.
113
[11]
A.A.A., A., Palm Oil Shell as Aggregate for Lightweight Concrete, in Waste
Materials Used in Concrete Manufacturing, S.Chandra, Editor. 1997, Noyes
Publ.
[12]
D.C., O., Palm kernel shell as a lightweight aggregate in concrete. Building
environment, 1990. 25, no.4: p. 291-296.
[13]
Teoh, C.H., The palm oil industry in Malaysia, From seed to frying pan,
prepared for WWF Swizerland. 2002.
[14]
A.Latiff, The biology of the genus Elaeis. In advances in oil research, 2000.
1: p. 19-38.
[15]
Available from: www.fao.org.
[16]
Mannan, M.A., A.J., Ganapathy C., Teo D.C.L. , Quality Improvement of Oil
Palm Shell (OPS) as Coarse Aggregate in Lightweight Concrete. building
and environment, 2006. 41: p. 1239-1242.
[17]
A.M., N., Properties of concrete. 3rd ed, New York: Pitman.
[18]
Mannan, M.A., G.C., Engineering properties of concrete with oil palm shell
as coarse aggregate. construction and building materials 2002. 16: p. 29-34.
[19]
M.L., G., Concrete technology. 2nd ed. 2000, New Delphi, India: Tata
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[20]
FO., O., Palm kernel shell as lightweight aggregate for concrete. ement and
concrete research, 1988. 18: p. 901-10.
[21]
Alengaram, U.J., J.M.Z., Mahmud H., Influence of cementitious materials
and aggregate content on compressive strength of palm kernel shell concrete.
[22]
A., S.S., Lightweight concrete made from palm oil shell aggregates and rice
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[23]
D.F., O., Concrete tehnology. 4th ed. 1979: London: Applied science
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[24]
Chen, HJ, Y.T., Lia TP, Huang YL, Determination of the dividing strength
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S., S., Civil engineering ,materials. 2nd ed. 1995: Upper saddle
river:Prentice hall.
114
[26]
Short A., K.W., Lightweight concrete. 3rd ed. 1978: London:Applied science
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O., O.F., Palm kernel shell as lightweight aggregate for concrete. ement and
concrete research, 1988. 18: p. 901-10.
[28]
Andrew Short, W.K., Lightweight concrete. 1962: Cr Books Ltd, London.
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L.C., S., The moisture movement of natural aggregate and its effect on
concrete. the durability of concrete. 1961: Prague.
[30]
FIP, FIP manual of lightweight aggregate concrete, London: Surry
University Press.
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Mindess S, Y.J., Concrete. 1981: Prentice Hall.
[32]
AM., B., Cement-based composites: Materials, mechanical properties and
performance. 1995, London: E & FN SPON.
[33]
A.S.T.M, Specification for lightweight aggregate for structural concrete, in
A.S.T.M. Standard C330-77(1997). 1997.
[34]
F.Y., L., Sound, noise and vibration control. 2nd ed. 1975, New York Van
nostrand reinhold.
[35]
Teo, D.C.L., M.M.A., Kurian V.J., Durability of lightweight OPS concrete
under different curing conditions. Materials and structures, 2010: p. 43:1-13.
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Mannan, M.A., B.H.B., Zain M.F.M., Islam M.N., Effect of curing
conditions on the properties of OPS-concrete. building and environment,
2002. 37: p. 1167-1171.
[37]
Mannan, M.A., Ganpathy C., Long term strength of concrete with oil palm
shell as coarse aggregate. Cement and concrete research, 2001. 31: p. 13191321.
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[40]
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Flexural Strength. 1983.
115
[42]
Institution, B.S., BS 1881: Part 203: 1983 – Recommendations for
Measurement of Velocity of Ultrasonic Pulses in Concrete 1983.
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Shan, S., Civil Engineering Materials. 2nded. Upper Saddle River: Prentice
Hall. 1995.
116
APPENDIX A
DESIGN OF REINFORCED CONCRETE BEAM
Design of Under Reinforced Concrete Beam according to the British Standard,
BS 8110: Part 1: 1997 – Structural Use of Concrete: Code of Practice for
Design and Construction
Information:
Length of beam,
L
=
1600 mm
Width of beam,
b
=
125 mm
Depth of beam,
h
=
150 mm
Nominal cover,
c
=
25 mm
Concrete strength,
fcu
=
25 N/mm2
Reinforcement strength,
fyv
=
460 N/mm2
Diameter of reinforcement,
Øbar
=
10 mm
Shear link,
Ølink
=
6 mm
117
Design:
Effective depth,
=
h – c – 0.5(Øbar)
=
150 – 25 – 0.5(10) – 6
=
114 mm
Fcc
=
Fst
0.405 fcu bx
=
0.95 fyAs
x
=
0.95 fyAs / 0.405 fcub
=
0.95 (460) (157) / 0.405 (25) (125)
=
54.21 mm
=
54.21 / 114
=
0.48 < 0.5
=
d – 0.45 x
=
114 – 0.45(54.21)
=
89.61 mm
=
0.95 fyAsz
=
0.95(460) (157) (89.61)
=
6.15 kNm
=
M/bd2 fcu
=
6.15 x 106 / (125) (114) 2 (25)
=
0.15 < 0.156
d
x/d
Therefore, under reinforced beam,
Level arm,
Ultimate moment,
z
M
K
Therefore, compression reinforcement is not required.
118
av/d
=
550/114
=
4.8
2 < av/d < 6
Hence, beam fail in bending and shear
Maximum shear force, P/2
Maximum shear force, V
=
6.15 / 0.55
=
11.18 kN
=
11.18 kN
Maximum shear stress at support,
119
v
100 As/bd
(400/d)0.25
=
V/bvd
=
11.18 x 103 / (125 x 114)
=
0.78 N/mm2 < 0.8(fcu0.5) = 4.38N/mm2
=
100(157)/(125 x 114)
=
1.10 < 3 (ok)
=
(400/114)0.25
=
1.37 >1 (ok)
=0.79(100As/bd)1/3(400/d)1/4(fcu/25)1/3/1.25
Concrete shear stress, vc
=0.79(1.10)1/3(1.37) (25/25)1/3 / 1.25
= 0.89 N/mm2
0.5 vc = 0.5(0.89)
= 0.45 N/mm2
Vc + 0.4
= 0.89 + 0.4
= 1.29 N/mm2
Hence,
0.5 vc < v < vc + 0.4
=
0.45 < 1.07 < 1.29
Provide minimum shear links for the whole length of beam
Asv / Sv
=
0.4bv / 0.95 fyv
=
(0.4 x 125) / (0.95 x 250)
=
0.21 N/mm2
Asv / Sv
=
0.21
Sv
=
56.6 / 0.21
=
270 mm > (0.75d = 85.5 mm)
Use shear link R6 (Asv = 56.6 mm2)
Use Sv = 80 mm
Hence, provide R6 – 80
120
Deflection:
M/bd2
Fs
f.u.t.t
=
6.15 x 106 / (125)(1142)
=
3.79 N/mm2
=
(2/3)(fy)(Areq/Aprov)(1/βb)
=
(2/3)(460)(1)(1)
=
306.67
=
0.55 + {(477 – fs) / [120(0.9 + M/bd2)]}
=
0.85 < 2
(L/d)basic
=
20
(L/d)allowed
=
20 x 0.85
=
17
(L/d)actual
=
1600/114
=
14
Cracking:
Allowed clear distance between bars =
S1
y
S2
H
155 mm
=
125 – (2 x 25) – 10 – (2 x 6)
=
53 mm < 155 mm
=
25 + 10 + 10/2
=
40 mm
=
(402 + 402)0.5 – 10/2
=
51.6 mm < 77.5 mm
(ok)
=
150 mm < 750 mm
(ok)
(ok)
121
Detailing:
122
APPENDIX B
CONCRETE MIX DESIGN
Stage 1:
Characteristic Strength
:
30 N/mm2 at 28 days
(Proportion Defective = 2.5%)
Standard Deviation
:
8 N/mm2
Margin
:
(k = 1.96), 1.96 x 8 = 16
Target Mean Strength
:
30 + 16 = 46 N/mm2
Cement Type
:
OPC
Coarse Aggregate Type
:
Crushed
Fine Aggregate Type
:
Crushed
Free Water Cement Ratio
:
0.52
Slump
:
30 – 60 mm
Maximum Aggregate Size
:
20 mm
Free Water Content
:
210 kg/m3
Stage 2:
123
Stage 3:
Cement content
:
210 / 0.52 = 403.8 kg/m3
Maximum Cement Content
:
550 kg/m3
Relatively Density of Aggregate
:
2.70 (assumed)
Concrete Density
:
2400 kg/m3
Total Aggregate Content
:
2400 – 405 – 210 = 1785 kg/m3
Grading of the Aggregate
:
Percentage passing 600 μm size = 40%
Proportion of Fine Aggregate
:
39 %
Fine Aggregate Content
:
1785 x 0.39 = 696.5 kg/m3
Coarse Aggregate Content
:
1786 – 695 = 1091 kg/m3
Hence, use 405 kg/m3
Stage 4:
Stage 5:
Quantities
Cement (kg)
Water (kg or
Fine
Coarese
L)
Aggregate
Aggragate
(kg)
(kg)
1 m3
405
210
700
1090
0.011 m3
4.5
2.3
7.7
12.0
0.011 m3 = Total up specimens of 3 cubes and 10% wastage
124
APPENDIX C
DETERMINATION OF WEIGHT POS REQUIRED
Bulk density of POS =
606.7 kg/m3
For 50% replacement of POS:
Weight required for coarse aggregate in concrete mixing is 15.26 kg for 3 cubes
with 35% wastage, since 50% of it will be replaced by POS, the weight of coarse
aggregate required is 7.63 kg.
1m3
:
2700 kg/m3
Assume volume occupied by coarse aggregate is X,
Hence,
X
:
7.63 kg
X
=
7.63 / 2700
=
2.83 x 10-3 m3
POS required =
=
(2.83 x 10-3 m3) x 606.7 kg/m3
1.71 kg