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CERAMIC TILES FROM Crassostrea iredalei (OYSTER) SHELLS
____________________________
A Research Paper presented to the Faculty
of the Department of Physical Sciences
Philippine Normal University
____________________________
In partial fulfillment of the requirements for the degree of
Bachelor of Secondary Education
Major in Chemistry
____________________________
by
April Mae V. Agbayani
Allen A. Espinosa
November 2006
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CERTIFICATE OF APPROVAL
This research paper entitled CERAMIC TILES FROM Crassostrea iredalei
(OYSTER) SHELLS by April Mae V. Agbayani and Allen A. Espinosa in partial
fulfillment of the requirements for the degree Bachelor of Secondary Education Major in
Chemistry, has been examined and recommended for acceptance and approval.
VIC MARIE I. CAMACHO
Research Adviser
NELSON GARCIA ADOLFO P. ROQUE
Panel Panel
REBECCA C. NUEVA ESPAA
Chair
This research paper is accepted and approved in partial fulfillment of the
requirements for the degree of Bachelor of Secondary Education Major in Chemistry.
MARIE PAZ E. MORALES
Date Head, Department of Physical Sciences
PHILIPPINE NORMAL UNIVERSITY
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ACKNOWLEDGEMENT
We wish to thank the following persons and institutions that, in one way or
another, helped make this research study a success:
Dr. Rebecca C. Nueva Espaa, our Chemical Research mentor and chair of the
board of panelist, for sharing her expertise in Chemical Research and the research process
as well.
Prof. Vic Marie I. Camacho, our research adviser, for her guidance and assistance
while in the process of doing our research.
Prof. Nelson Garcia, our panel, for his guidance and assistance while doing our
methodology or experimentation. For always reminding us of a certain lesson in life, that
is, there are ideas that are possible and that there are also ideas which are not possible and
that we have to think critically before pursuing something and the ones we done wrong
should serve as a lesson so we might not repeat it.
Prof. Adolfo P. Roque, our panel, for sharing his ideas regarding our research.
Engr. Benito D. Shea of the Department of Mining, Geology and Ceramics
Engineering of Adamson University for sharing his knowledge and for guiding us in our
methodology.
Prof. Cecilia F. Reynales, Senior Science Research Specialist of the Materials
Science Division of the Department of Science and Technology for explaining to us what
had happened to our research.
Prof. Antonio G. Dacanay, our statistics mentor, for lending us statistics book.
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Genelita P. Gallenito and Antonio V. Lumbo III, student assistants of the
Department of Mining, Geology and Ceramics Engineering of Adamson University for
patiently assisting us in the ceramics engineering laboratory.
Mr. Ronnel Pantig, SRC technician, for patiently providing materials and
chemicals needed in our experimentation.
Dr. Susan R. Arco and Dr. Florian R. del Mundo of the Institute of Chemistry of
the University of the Philippines and Prof. Gilbert U. Yu of the Department of Chemistry
of the Ateneo de Manila University for giving ideas and possible topics for research
while in the process of searching for a subject for research.
Ma. Jesusa O. Araneta, our classmate, for sharing her Bato-Balani journal which
has been a great help to the researchers.
Reinier Augustus S. Isidro and Sherryl R. Jamito, our kuya and ate, for providing
us a soft copy of their research paper about concrete blocks.
The family of April Mae V. Agbayanis husband, Allan Ray Berganos, especially
Mr. Loloy Berganos for helping us do some of the laborious parts.
Leah Mae G. Cariquitan, Christina C. Cuevas, Lea B. Florendo, Vivian Mary S.
Palma and Carla Mari A. Pareja, our dear classmates, for helping us transport our
research materials from PNU to AdU and vice versa.
Department of Science and Technology - Industrial Technology Development
Institute Library for providing us lots of information regarding ceramic tile making.
University of the Philippines College of Science Library for providing us lots of
information about Crassostrea iredalei (oyster) shell.
Our dear classmates, for the friendship and encouragement.
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Our family, for the unconditional love, understanding and support they extended
to us.
Our Creator, for giving us life, for us to experience the sweetness and bitterness of
living which have certainly made us better persons.
A. M. V. A
A. A. E
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ABSTRACT
This research study entitled Ceramic Tiles from Crassostrea iredalei (Oyster)
Shells aimed to investigate the feasibility of the Crassostrea iredalei (oyster) shell as
base for ceramic tile making. The Crassostrea iredalei (oyster) shell were substituted to
silica sand in 40%, 50%, 60%, 100% and 0% substitution respectively. Slip casting was
the forming method used in producing the tile body. Three firing procedures were utilized
using the bisquit and glost firing. The produced tiles were subjected to impact strength
and porosity tests. In the one-way ANOVA used in the study for comparing the said
physical properties of the produced tiles with that of the commercial tiles, it shows that
tile C3 is the most feasible among all the experimental tiles. Meaning, it is the only tile
that is comparable with the commercial tiles in terms of impact strength and porosity.
This also shows the feasibility of producing tile with 60% concentration of calcium
carbonate and with a bisquit firingglazingglost firingproduct firing procedure.
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TABLE OF CONTENTS
Title Page i
Approval Sheet ii
Acknowledgement iii
Abstract vi
List of Figures ix
List of Tables x
List of Appendices xii
Chapter
1 Introduction 1
Objectives of the Study 2
Significance of the Study 2
Scope and Limitations of the Study 3
Definition of Terms 3
2 Crassostrea iredalei (Oyster) Shell: Chemical Components and Uses 4
Ceramic Tile Production 7
Physical Properties of Ceramic Products on the Fired State 13
Local Studies
Nata de Coco Reinforced Styrofoam as Tiles 18
Feasibility of Foam Polystyrene and Powdered
Talaba Shells as Tiles 19
3 Materials and Reagents 21
Research Design 22
Phase I: Preparation of Ceramic Tiles from Oyster Shells
Gathering of Samples 23
Mold Making 23
Preparation of Mixtures 24
Molding and Drying 24
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Glaze Preparation 25
Glaze Application 25
Firing Technology 25
Phase II: Tests on Physical Properties
Test for Impact Strength 26
Test for Porosity 27
4 Results and Discussions 28
5 Conclusion and Recommendations 46
Bibliography 48
Appendices
A Raw Data and Computations for Impact Strength Test 50
B Raw Data and Computations for Porosity Test 58
C Research Pictorials 66
Curriculum Vitae 70
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LIST OF FIGURES
Figure
2.1 Crassostrea iredalei (oyster) shell
2.2 Decomposition of calcium carbonate (CaCO3) into calcium oxide (CaO)
and carbon dioxide (CO2) at a very high temperature
2.3 Pulverized Crassostrea iredalei (oyster) shell
2.4 Process of ceramic tiles production
3.1 The schematic diagram of the entire research
3.2 The dimensions of the tile molder
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LIST OF TABLES
Table
2.1 Chemical Components of Crassostrea iredalei (Oyster) Shell
4.1 Description of Mixtures, Molding and Drying
4.2 Firing Technology
4.3 Result of Impact Strength Test for Control Tiles F and G
4.4 Result of Impact Strength Test for Mixture A
4.5 Summary of one-way ANOVA applied to tile A2 versus tile F or G
4.6 Result of Impact Strength Test for Mixture B
4.7 Summary of one-way ANOVA applied to tile B3 versus tile F or G
4.8 Result of Impact Strength Test for Mixture C
4.9 Summary of one-way ANOVA applied to tile C3 versus tile F or G
4.10 Result of Impact Strength Test for Mixture E
4.11 Summary of one-way ANOVA applied to tile E1 versus tile F or G
4.12 Result of porosity test (in percent apparent porosity, %Pa) for control tiles
F and G
4.13 Result of porosity test (in percent apparent porosity, %Pa) for mixture A
4.14 Summary of one-way ANOVA applied to tile A2 versus tile F
4.15 Result of porosity test (in percent apparent porosity, %Pa) for mixture B
4.16 Summary of one-way ANOVA applied to tile B1 versus tile F
4.17 Result of porosity test (in percent apparent porosity, %Pa) for mixture C
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4.18 Summary of one-way ANOVA applied to tile C3 versus tile F
4.19 Result of porosity test (in percent apparent porosity, %Pa) for mixture E
4.20 Summary of one-way ANOVA applied to tile E1 versus tile F
4.21 Summary of results for the best tiles produced
4.22 Cost of materials utilized in the study
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LIST OF APPENDICES
Appendix
A Raw Data and Computations for Impact Strength Test
B Raw Data and Computations for Porosity Test
C Research Pictorials
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Chapter 1
INTRODUCTION
Building commercial and residential infrastructures in our country is fast growing.
One of the building materials is ceramic tile that is used as floorings in bathrooms, dining
area, function halls, etc. Because of this, there is a demand of ceramic tiles and its
industry is booming.
On the other hand, every year, various solid wastes in our country have been a
great problem to our government. One example is the shells of Crassostrea iredalei
commonly known as oyster found near the seashores. It makes the seashore looks grimy
and its foul odor when fresh is disgusting which is not inviting local and foreign tourists
to visit tourist spots like beaches. It also serves as silt for reproduction of flies and other
oil-causing insects, which are carriers of disease-causing bacteria and viruses.
These shells are known fossil that contains ninety seven and a half percent
(97.5%) calcium carbonate (CaCO3)1, which is a good source of calcium oxide (CaO)
that made these shells rigid and firm. The presence of calcium carbonate (CaCO3) would
make it an ideal component for tiles.
This information brought the idea to the researchers to use the Crassostrea
iredalei (oyster) shells as raw material for ceramic tile making. Due to its high
concentration of calcium carbonate (CaCO3), the proponents therefore would like to
substitute it for the main material in ceramic tile making.
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Objectives of the Study
The main objective of the study is to investigate the feasibility of the Crassostrea
iredalei (oyster) shell as base for ceramic tile making. Specifically, it aims to:
a. Utilize Crassostrea iredalei (oyster) shells as substitute to silicon dioxide (silica
sand) in ceramic tile making;
b. Test the physical properties of the produced ceramic tiles:
i. Impact Strength;
ii. Porosity: and
c. Compare the ceramic tile made of Crassostrea iredalei (oyster) shells to
commercially available ones such as the Mariwasa Ceramic Tiles and Floor
Center Ceramic Tiles in terms of impact strength and porosity.
Significance of the Study
This study was conducted to eliminate solid waste pollution caused by
Crassostrea iredalei (oyster) shells on the seashores by recycling it. Moreover, it can also
prevent the rapid growth of population of insects like mosquitoes living in the shells,
which are carriers of disease-causing bacteria and viruses. In addition, new product
means new opportunity for export and new hope for economic progress.
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Scope and Limitations of the Study
The focus of the study is on the utilization of Crassostrea iredalei (oyster) shells
as raw material for ceramic tiles. The process of ceramic tile making including tests on
properties such as impact strength and porosity are therefore incorporated in the study.
Definition of Terms
Ceramic tile is the tile made from Crassostrea iredalei (oyster) shell and some basic
components of a commercially available ceramic tile.
Impact Strength is the ability of ceramic material to bear crushing loads.
Oyster shells are the shells derived from Crassostrea iredalei.
Porosity is the penetration of liquids and vapors through the material that usually
causes structural damage.
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Chapter 2
REVIEW OF RELATED LITERATURE
This section includes literature concerning the topic that the researchers deemed
important and relevant. It encompasses some background on Crassostrea iredalei
(oyster) shells and the process of ceramic tile making. Also, it includes local studies on
tiles made from locally available materials.
Crassostrea iredalei (Oyster) Shell: Chemical Components and Uses
According to studies, ninety seven and a half percent (97.5%) of the chemical
components of Crassostrea iredalei (oyster) shell are calcium carbonate (CaCO3) or
limestone.1 It is embedded between the layers of an organic substance known as
conchiolin.2 Calcium carbonate (CaCO3) is a compound used in brick making for its high
compressive strength and boiling point.3 The presence of calcium carbonate (CaCO3) in
the shells indicates that it could be used as a source of calcium oxide (CaO), which was
shown to strengthen blocks and dental fillings.
Figure 2.1 Crassostrea iredalei (oyster) shell
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Table 2.1 Chemical Components of Crassostrea iredalei (Oyster) Shell1
CaCO3 (calculated from Ca) 97.5 % Boron 1400 ppm
Calcium 39.00 % Titanium 100 ppm
Silica as SiO2 (calculated from Si) < 0.01 % Lead less than 15 ppm
Sodium 9200 ppm Copper 9 ppm
Magnesium 1400 ppm Lithium less than 10 ppm
Iron 430 ppm Arsenic less than 2.50 ppm
Strontium 1400 ppm Nickel 75 ppm
Manganese 430 ppm Heavy metals as Pb less than 20 ppm
Aluminum 3500 ppm
On a physical analysis done, calcium carbonate is found to have a dry brightness
of 92.1, moisture at 105C of 0.084%, oil absorption of 18.9g oil per 100g of oil,
specific surface area of 0.423m2/g, weight/solid per gallon of 23.1lbs, specific gravity of
2.71, pH of 9.8, hexagonal particle shape, and density of 1.1 g/cm3. Its general uses
includes synthetic/cultured marble, ceramic floor tiles, stucco, caulking compound,
building products, polishing compound, grouting and thin set mortars, abrasive in
powdered cleansers, sealants, adhesives, putty, and glues, paints (water-based), animal
feeds, insecticides, plastics, PVC pipes, carpet underlays and paper.4
Other than being a good ingredient in strengthening tiles, researchers in Florida,
USA and Korea have developed and successfully tested a new process to convert waste
oyster shells into a compound that cleanses water of phosphorus, a common pollutant in
urban, agricultural and industrial runoff. Heating the shells at very high temperatures in a
nitrogen-rich atmosphere for about an hour efficiently converts their contents into a form
of calcium oxide (CaO). Crushed-up oyster shell forces the phosphorus to leave the
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solution, become small particles and precipitate out, or fall to the bottom of the tank,
where it can then be collected and discarded.5
CaCO3(s) CaO(s) + CO2(g) Hrxn = 178.1 kJ/mol Figure 2.2 Decomposition of calcium carbonate (CaCO3) into calcium oxide (CaO)
and carbon dioxide (CO2) at a very high temperature.
Moreover, oyster shells are processed and made into oral calcium supplement
tablets because of its high calcium content. Studies shown that thirty nine percent (39%)
of the chemical components of oyster is calcium.1, 6
Furthermore, oyster shells are crushed into fine particles to be used as an organic
fertilizer. Studies shown that finely crushed oyster shells raises pH in acidic soils. It also
has other nutrients and micronutrients, which keeps the natural balance of the soil.7
Figure 2.3 Pulverized Crassostrea iredalei (oyster) shell.
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Ceramic Tile Production
Tiles are similar to bricks. They differ in uses, in shapes, and in finishing. While a
brick is in the form of a block, a tile is in the form of a sheet. Both are made from the
same process and materials but the tile may go through glazing which can give it a
smooth finish. Tiles are used for walls and flooring.8 Figure 2.4 shows the schematic
diagram of ceramic tile production.
Ceramics is defined as products made out of clay and other earth materials that
can be formed or molded into various shapes, then dried and fired into hardness at a
given temperature.9 Ceramic tile is made of clay. After the formation of the tile body, it
goes through a firing process.10
Basic ceramic raw materials include clay, feldspar and
silica. Clay is an earth material that forms a sticky mass when mixed with water. When
wet, this mass is readily moldable, but when dried, it becomes hard and brittle and retains
its shape. When heated to redness, it becomes still harder and is no longer susceptible to
the action of water. Such a material clearly lends itself to the making of articles of all
shapes. Clays can be classified into kaolin/white clay and ball clay. Kaolin/white clay is
the white-burning clay because of its low iron content. Because of its relative purity, it is
more refractory than other clays. It is the base to which other ingredients are added to
develop the desirable properties. Its strength varies almost directly with plasticity. 9
In a
chemical analysis, kaolin is found to contain 46.87% SiO2, 37.60% Al2O3, 0.27% Fe2O3,
0.85% TiO2, 0.56% CaO, 0.09% Na2O, 0.10% K2O and 13.7% LOI.11
Ball Clays are
extremely plastic clays that fire nearly white though is often black in the raw state. They
usually contain slightly more impurities than kaolin, but are used to increase the plasticity
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and workability of the body. In a chemical analysis, ball clay is found to contain 56.74%
SiO2, 26.94% Al2O3, 1.53% Fe2O3, 1.26% TiO2, 0.25% CaO, 0.64% MgO, 3.42% K2O,
0.41% Na2O and 8.81% LOI.12
Feldspars are used as flux in ceramic bodies. When the
body is fired, the feldspar melts and forms a molten glass that causes the particles of clay
to cling together. When this glass solidifies, it provides strength and hardness to the body.
It is also a good source of soda and potash. Chemically, the feldspars are silicates of
aluminum, containing sodium, potassium, iron, calcium, or barium or combinations of
these elements. Silica or silicon dioxide in the form of quartz, is used in nearly all
ceramic bodies for three reasons: to reduce the drying shrinkage and thus help prevent
cracking of the piece, to give firing qualities by reduction of the firing shrinkage and to
act as a sort of skeleton to hold the shape of the piece in the kiln. 8
Silica, along with
alumina (silica-alumina), forms a major part of the crystal lattice of clay minerals. These
decompose on firing and form part of the microstructure of clay based ceramics such as
earthenware, stoneware and porcelain.13
The proportion of clay (kaolin and ball clay),
feldspar and silica sand is 40%:30%:30%.14
Raw materials like clays, talc and other minerals of ceramic tile are quarries and
refined. Great care is taken in the proper mixture of these materials, as one is critical to
the success, quality and characteristics of the product produced. Once the raw materials
are quarries prepared, and properly mixed, the tiles may now be formed. There are few
common means of forming the tile. First is dust press, wherein an almost dry mixture of
clays, talc, and other ingredients are pressed into a mold at extremely high pressures.
Second is extrusion, wherein the ingredients are slightly wetter and are forced through a
nozzle to form the desired tile shape. Third is slush mold or wet pour, wherein a much
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wetter mixture of ingredients is poured into a mold to form the desired shape. Fourth is
rampress, which is very similar to dust press method, except that the size of the tile
shapes are generally much larger.10
Pressing is a kind of hand forming method in which
the clay must be soft enough to flow into the cavity of the mold while under pressure.
Pressed ware is commonly handled immediately after pressing and must be strong
enough to retain its shape. 9
Slip casting method of forming the tile body includes the procedure in where
sodium silicate is added to the clay mixture as a defloculant which is added to obtain
good fluidity. Sodium silicate is added 0.3-0.6% of the total weight of the clay mixture on
the other hand 30-45% of the total weight is water. The specific gravity of the mixture
should fall within the range of 1.6-1.8. The mesh sieve number of particles should fall
from 60-80. Plaster of paris (CaSO4 0.5H2O) is commonly used as a molder. 9
In general, there are essentially three basic production cycles to which the entire
range of different types of ceramic floor and wall tile can be referred. The first of these
three production cycles, based on single firing technology, is used to manufacture
unglazed tile. The types of unglazed tile produced with this production technology are
cotto, red stoneware, porcelain stoneware and clinker (klinker). The second of these is
based on double-firing technology, which obtains its name from the fact that two distinct
firing treatments are employed, i.e. one to consolidate the tile body and the other to
stabilize the glazes and decorations applied onto the fired tile body.
This production cycle is used for the manufacture of the
majolica, cottoforte, and earthenware (white body). The third of these cycles is based on
single-firing technology. The glazes and decorations are applied onto the dried, but still
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unfired, tile body. Then it is subjected to a single heat treatment single-firing. During this
firing, consolidation of the tile body and stabilization of the glazes takes place at the same
time. This production cycle is use for the manufacture of single-fired whiteware and
redware (monocottura and monoporosa) and glazed klinker.15
Glazes constitute an important element of ceramics. It maybe defined as a glassy
coating melted in place on a ceramic body which may render the body smooth, non-
porous and of desired color or texture. The primary function of glazes is to give strength
and durability of products. Likewise, glaze protects ceramic wares from contamination,
from the action of acids and alkaline and from scratching. They are also used for
decoration purposes. Lime or calcium oxide (CaO) is an example of a glaze material. Its
sources are pure calcium carbonate, whiting, limestone, dolomite and anorthite. Lime is a
principal flux in medium and high temperature glazes but it is not very effective at lower
temperatures. It contributes stability, hardness and durability.9
In the preparation of glaze, the universal method is to mix the glaze ingredients with
water to form a suspension or slip. Weighing of glaze batches should be done in scales of
good construction. Sensitive and precise to the smallest quantities required. Small
quantity of glaze batch is prepared in mortar and pestle while in large quantity, pebble
milling is introduced. 9
There are several ways of applying glaze slip on ceramic wares. One is dipping which
involves having a small receptacle filled with glaze into which the ceramic piece is
immersed into the glaze shaken vigorously to remove surplus of glaze. Another is
pouring on which a quantity of glaze is poured into a ceramic piece until the surface of
ware is covered with it. Brushing in which the application is done with the use of soft
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brush, even strokes are required to attain a good finish. Then, spraying in which the
application is done with the use of air compressor and spray gun. 9
Bisquet firing is a technique where the dried ware should be fired to strengthen
the body's resistance to strain and stress. Firing of wares depends on the product required.
Porcelain, stoneware, and other wares to be glazed are fired at temperature of 800-900
degrees Celsius; for bricks, roof tiles, and other earthenware that do not need to be
glazed, firing temperatures should reach at least its semi-vitreous state at about 900
degrees Celsius to 1200 degrees Celsius. Firing state should be normal and slow due to
water smoking, dehydration, and other chemical and physical reactions undergone by the
body from a dried state to its maturing state. Usually, firing is under an oxidizing flame. 9
Glost Firing is a technique where bisquet fired walls are glazed and then fired.
Temperature for glost firing depends on the glaze used. Temperature ranges from 800-
1050 degrees Celsius; for stoneware and porcelain, temperature ranges from 1150-1380
degree Celsius. Oxidizing and reducing atmospheres inside the kiln depend on the glaze
used, tone effect and product required. Usually, the glazed wares are first fired in an
oxidizing atmosphere up to 1100 degrees Celsius, the wares are fired in reducing flame;
lastly, the firing becomes slightly reducing or neutral. This step is called reducing firing.
There are bodies which could be glaze on its green or dried state, then fired. This is called
monofiring. 9
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Figure 2.4 Process of ceramic tiles production14
Pre-mix Clay Body
Weighing
Blunging
Forming (Slip Casting)
Retouching
Drying
Bisquit Firing
Glaze Application
Glost Firing
Quality Control
Packaging
+ water defloculant
underglaze decoration application
brushing, spraying, pouring
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Physical Properties of Ceramic Products on the Fired State
Compressive Strength9
The compressive strength of a ceramic material is a measure of its ability
to bear crushing loads. Since ceramics normally break under tension, its true
compressive strength is difficult to measure. For a correct measurement of the
compressive strength of a ceramic material, more care in simple preparation
should be done. In particular, the specimen facing the bearing load must be
absolutely flat and parallel. If this criterion is not met, the load will be carried
unevenly by the specimen causing failure at low loads thus giving low
compressive strengths. Cushioning materials are often used to distribute the load
uniformly over the bearing surfaces.
The compressive strength (Sc) is represented by the equation:
Sc = P / A
where: P = the crushing load at failure (kg)
A = the cross sectional area of the test sample (cm2)
Hardness9
Hardness is one of the most important properties of ceramics, but because
of brittleness of ceramic materials hardness is also one of the most difficult
properties to measure. Several methods have been developed which give fairly
reliable results. Usually, a diamond stylus is forced into the surface of a ceramic
specimen under a standard load and depth of penetration is measured. The test is
run on polished samples employing a forty-five kilograms (45kg) load on the
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diamond stylus. Although the numerical difference between alumina samples of
various compositions is small, the test results are quite reliable.
The second method and one of the most common tests used for hardness is
the Mohs scale. This scale uses ten standard minerals, each of which will scratch
all minerals below it on the scale. Ceramics are rated on this scale by scratch trials
with the standards: 1) Talc, 2) Gypsum, 3) Calcite, 4) Fluorite, 5) Apatite, 6)
Orthoclase, 7) Quartz, 8) Topaz, 9) Corundum and 10) Diamond.
Modulus of Rupture (MOR) 9
The modulus of rupture is the fracture strength of the materials under a
bending load. It is one of the quality control tests for the measurement of strength.
The MOR measurement is made on a long bar of either a rectangular or
circular cross section; supported near its ends, with a load applied to the central
portion of the supported span. Any standard testing machine of suitable capacity
may be used, so long as the specimen is properly mounted. In order to yield
correct results, the bar must fracture at the center. The MOR is represented by the
equation:
MOR= 3/2 (PL/bd2)
where:
P= the load required to break the bar (kg)
L= the span, distance between the outer supports (cm)
b= the width of the bar (cm)
d= the depth of the bar (cm)
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Using cylindrical bar, the MOR is given by the equation:
MOR = 8PL / D3
where: D= the diameter of the cylindrical bar (cm)
Such a test assumes the pieces to be uniformly strong through all cross
sections, which is not strictly true. To average out the variations, ten specimens
are used for the test and individual values with more than 20% variation from the
average are discarded. The most important factors in the MOR determinations are
the rate of loading, the ratio of span to specimen thickness, and the specimen
alignment. The specimen should be carefully aligned in the specimen holder so
that the latter will not twist during the operation.
Porosity9
The porosity of a ceramic sample, particularly a fixed ceramic sample,
should be carefully controlled. The greater the porosity of a sample, the more
likely the penetration of liquids and vapors through the materials and usually,
such penetration is accompanied by structural damage to the product. Example:
refractories with high porosity will suffer internal chemical attack as a result of
the penetration of slags into the interior. Also, table-ware that exhibits high
porosity would absorb various substances during use and becomes permanently
stained and unsanitary. There are few ceramic products produced today which do
not have carefully controlled pore structures. Only the open pore volume,
sometimes called the apparent pore volume, can be directly measured. When this
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volume is expressed as a percentage of the bulk volume of the sample, it is called
the percentage apparent porosity
% Pa = Vop / Vb x 100
where: Pa = percentage apparent porosity
Vop = the volume of open pores (cm3)
Vb = the bulk volume of the sample (cm3)
Substituting the weight quantities in the equation, the result is:
% Pa = Wm Wd / Wm Wmm x 100
where: Wm = the unsaturated (dry fired/weight/g,kg)
Wd = the unsaturated weight of the sample ( that is all the open
pores are filled with water)
Wmm = the weight of saturated sample when it is submerged in
liquid for five hours (g, kg)
Percent Water Absorption9
Generally, the absorption test is the best single indicator of the quality of a
ceramic body. It is a measure of the degree of vitrification achieved, in as much
as, when the firing temperature of a body is increased, its absorption steadily
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drops, and, as the absorption decreases, the mechanical strength of the body is
greatly improved.
Percentage water absorption is the ratio of the weight of water absorbed
during saturation to the weight of the sample when it is saturated. It is represented
by the equation:
%WA = Wm-WD/WD x 100
where: WA = percentage water absorption
Wm = the weight of the water-saturated (g, kg)
WD = the weight of unsaturated (dry fired) sample (g, kg)
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Local Studies
This section includes literature on tile making using locally available materials
and the tests conducted to investigate the feasibility of the tiles produced.
Nata de Coco Reinforced Styrofoam as Tiles16
The rise of the nata de coco industry and the many uses of the said food product
prompted a group of students to do research on the said fibrous material. An idea came
up to use the cellulose fibers of nata de coco to reinforce the common Styrofoam.
Nata de coco was placed in a large container then boiled in a 25% sodium
hydroxide solution to remove the noncellulosic material. The mixture was allowed to
settle for 10-15 minutes until the material had separated. The cellulose was then collected
and placed in the drying oven for a few minutes to dry. The oven was occasionally
observed to prevent the sheets from burning. The dried cellulose was then cut into small
pieces and was placed in the Wiley mill for grinding. The powdered cellulose was then
stored until the Styrofoam was ready for mixing. The Styrofoam was placed in a
container and toluene was added to dissolve the material. The powdered cellulose was
mixed with the Styrofoam and toluene. The mixture was stirred until all the Styrofoam
had been dissolved into pure polystyrene.
Four treatments of different ratios of Styrofoam with cellulose were prepared
during the production; the four mixtures were as follows: 10:90, 15:85, 20:80, and 25:75
percent of cellulose with Styrofoam, respectively. Pure Styrofoam and pure cellulose
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31
were also held as basis for comparison. The mixtures were mixed very evenly and
carefully. When the cellulose and Styrofoam were mixed completely in each of the
different treatments, the resulting polymer blend was poured into aluminum containers.
The mixtures where then allowed to harden.
Tests were made to examine the quality of the resulting material. Tests on
flexibility, flammability, and water absorption were done. The test on flexibility was
done by noting the expansion of the samples when exposed to the same tension. The
flammability test was based on whether the tiles are easily burned or not. The water
absorption test was done by submerging each sample into water and left there for a
certain time then weighed to note the change in mass. The texture was also observed to
see which appears to be closest to Styrofoam.
Through the flexibility, flammability, and water absorption qualitative test and
with the aid of statistical tests such as Friedmanns statistical test prove that the product
cannot substitute tiles since they do not possess the properties of commercially produced
tiles.
Feasibility of Foam Polystyrene and Powdered Talaba Shells as Tiles17
The study deals with the recycling of polystyrene foam or foam polystyrene more
popularly known as Styrofoam. Foam polystyrene (FPS) was reused as an ingredient in
making tiles. The tiles were made as follows: FPS was mixed with ground talaba shells
after being dissolved in premium gasoline. This mixture was then placed into molds
having 2.54 cm x 2.54 cm x 1.27 cm dimensions and was left to air dry. Three mixtures
of FPS and gasoline with ground talaba shells were prepared. The mixtures have the
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32
ratios of 60:40, 50:50, and 40:40. It was then removed from the molds and sanded into
tiles having dimensions of one by 2.54 cm x 3.18 cm. The resulting tiles were tested
(Impact Test) against some commercial tiles involving a test for the breaking of the tiles
upon receiving the impact of a load. The results showed that the experimental tiles were
comparable with the control.
Impact Test
The strength of the tiles will be tested in the following manner. The tiles would be
placed on the floor underneath a piece of metal. A load would be dropped on the metal.
This would be done on each of the tiles with increasing weight. A commercial tile would
also be tested in this manner to compare its strength with that of the experimental tiles.
Height = 0.68 m
Load 1 = 0.587 kg
Load 2 = 1.1567 kg
Load 3 = 1.7577 kg
Rating Scale:
5 no cracks, no damage
4 chipped; few cracks
3 more cracks but did not break into fragments
2 broke into fragments
1 extensive damage; crushed
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33
Chapter 3
METHODOLOGY
This section includes the details how the study was conducted, that is, the plans
for different stages, experimentation, tools, special procedures or techniques.
Materials and Reagents
For the pulverization of Crassostrea iredalei (oyster) shells, pounding steel is
used while for the straining of the pounded shells, a metal screen with fine holes (70
mesh sieve) is used.
For the preparation of mixtures, basins are used in the mixing of the pounded
shells with the feldspar, kaolin, ball clay, sodium silicate and water. For further mixing, a
labo mill is used.
For master mold making, plaster of paris and water is used.
For the molding and drying, a mold made of plaster of paris is used.
For glaze preparation, calcium oxide, carboxymethyl cellulose and water is used.
For the firing, a firing machine is used.
For the impact test, a meter stick, loads of different weight and a flat metal are
used.
For the porosity and water absorption test, a triple beam balance and a basin are
used.
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34
Research Design
Phase I: Preparation of Ceramic Tiles from Crassostrea iredalei (Oyster) Shells
Figure 3.1 The schematic diagram of the entire research.
Gathering of Crassostrea iredalei (Oyster) Shells
Washing of Impurities by Boiling
Air & Sun Drying
Pounding/Pulverizing & Filtering/Straining
Master Mold Making
Preparation of Mixtures (Slip Casting)
Experimental
2:3 (A)
1:1 (B)
3:2 (C)
1:0 (D)
0:1 (E)
Molding & Drying
Glaze Preparation
Bisquet Firing Final Product
Glaze Application
Glost Firing
Final Product
Impact Strength Porosity
Phase II: Test for Physical Properties
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35
Phase I: Preparation of Ceramic Tiles from Crassostrea iredalei (Oyster) Shells
Gathering of Samples
The fifty kilograms (50kg) or one (1) sack of Crassostrea iredalei (oyster) shells
were obtained from the shores of Maragondon, Cavite on August 4, 2006.
After the shells were collected, it was washed of impurities by boiling. It was
done for ten (10) minutes and then air-dried and sun-dried for twenty four (24) hours.
After drying, the shells were pounded using pounding steel. The pounded shells are
subjected to a screen with fine holes (70 mesh sieve) to allow only the passage of finer
shell particles. Shells that were left on the screen will be pounded again until such time
that it pass through the screen with fine holes.
Mold Making
Each mixture of plaster of paris was carefully mixed for three (3) to four (4)
minutes until it is about to start setting. The mixtures composition is three hundred
grams (300g) of plaster of paris added to sixty-seven milliliters (200mL) of water.
The mixture was poured in the master mold. The master mold has a plastic
walling to prevent sticking of the plaster of paris. The mater mold is made up of wood
and is prepared by a carpenter.
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36
Preparation of Mixtures
For the experimental group, five (5) different mixtures were made: mixtures A, B,
C, D and E. The composition of each are: 2:3, 1:1, 3:2, 1:0, 0:1 (pulverized shells : fixed
mixture of feldspar, kaolin and ball clay ratio of mass). The composition of the fixed
mixture was 3:2:1 (feldspar : kaolin : ball clay ratio of mass). The composition of mixture
D was 1:1 (pulverized shells : feldspar ratio of mass). The composition of mixture E was
0:1 (pulverized shells: fixed mixture of feldspar, kaolin and ball clay ratio of mass).
Slip Casting was used in the preparation of mixtures. Sodium silicate is added to
the mixtures. It was 0.5% of the total weight of the clay mixture on the other hand 36% of
the total weight is water.
Molding and Drying
The prepared mixtures were poured into corresponding molds with 4 in x 4 in x
0.5 in in dimensions. Fifteen (15) replicates were prepared for each mixture. The
mixtures were left over to dry.
Figure 3.2 The dimensions of the tile molder
4 in 4 in
0.5 in
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37
Glaze Preparation
Thirty grams (30g) of lime or calcium oxide (CaO) was mixed with seventy
milliliter (70mL) of water to form a suspension or slip. Three tenths grams (0.3g) of
commercially prepared carboxymethylcellulose (CMC) was added to it. The mixtures
specific gravity is checked using a hydrometer. The specific gravity of the mixture was
1.5.
Glaze Application
Brushing glaze application is used. It was done with the use of a soft brush.
Firing Technology
Four (4) tiles from mixtures A, B, C, and E are subjected to bisquit firing without
glaze at a temperature of 900C. They were referred to as A1, B1, C1, and E1.
Another four (4) tiles from mixtures A, B, C, and E are subjected to glost firing
with glaze at a temperature of 900C. They were referred to as A2, B2, C2, and E2.
The last four (4) tiles from mixtures A, B, C, and E are subjected to bisquit firing
without glaze at a temperature of 900C. The glaze was added to the tile after firing. The
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38
glazed tiles were subjected to glost firing at a temperature of 1100C afterwards. They
were referred to as A3, B3, C3, D3 and E3.
Phase II: Tests for Physical Properties
Tests
Impact Strength Test
Two (2) tiles from A1, A2, A3, B1, B3, C1, C2, C3, E1, E2 and E3 and two
commercially available tiles namely Mariwasa Ceramic Tiles and Floor Center
Ceramic Tiles which were referred to as F and G respectively are subjected to
Impact Strength Test.
The tiles would be placed on the floor underneath a piece of metal. A load
would be dropped on the metal. This would be done on each of the tiles with
increasing weight. The weight, height and rating scale is shown below.
Height = 0.68 m
Load 1 = 100 g
Load 2 = 200 g
Load 3 = 500 g
Rating Scale:
50 no cracks, no damage
40 chipped; few cracks
30 more cracks but did not break into fragments
20 broke into fragments
10 extensive damage; crushed
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39
Porosity Test
Two (2) tiles from A1, A2, A3, B1, B3, C1, C2, C3, E1, E2 and E3 and two
commercially available tiles namely Mariwasa Ceramic Tiles and Floor Center
Ceramic Tiles which were referred to as F and G respectively are subjected to
Porosity Test.
Each tile was weighed using a triple beam balance to get its dry fired mass
(Wm). After weighing, each tile was dipped in water instantaneously to fill the
open pores then it was weighed again to get its unsaturated mass (Wd). After
weighing, the tiles were submerged in water for five (5) hours and were weighed
again to get its saturated mass (Wmm). To get the percent apparent porosity (%Pa),
the values gathered from weighing was then be substituted to the equation:
% Pa = Wm Wd / Wm Wmm x 100
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40
Chapter 4
RESULTS AND DISCUSSIONS
This section includes facts and figures gathered in the experimentation process of
utilizing oyster shells as substitute to silica sand in ceramic tile making. The results of the
study were described in the preceding sections.
The oyster shells were mixed with five (5) treatments, referred to as mixtures A,
B, C, D and E. The proportions of each mixture were 2:3, 1:1, 3:2, 1:0 and 0:1
(pulverized oyster shells : fixed mixture of ball clay feldspar and kaolin ratio of mass)
respectively. Refer to Table 4.1 for the data.
Table 4.1 Description of Mixtures, Molding and Drying
* Pulverized shells: fixed mixture of ball clay, feldspar and kaolin ratio of mass
Mixture Proportion* No. of Tiles
Molded
No. of Tile Body
Formed Description
A
2:3
12
12
When placed in the plaster of
paris mold, it dries, hardens & forms a tile body.
B
1:1
12
12
When placed in the plaster of
paris mold, it dries, hardens & forms a tile body.
C
3:2
12
12
When placed in the plaster of
paris mold, it dries, hardens
& forms a tile body.
D
1:0
12
0
When placed in the plaster of
paris mold, it dries but did
not harden, therefore not
forming a tile body.
E
0:1
12
12
When placed in the plaster of
paris mold, it dries, hardens
& forms a tile body.
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41
As shown in Table 4.1, mixtures A, B, C and E dries, hardens and forms a tile
body. No cracking occurs when removing it in the plaster of paris mold. The said
mixtures dry because the plaster of paris mold absorbs its water content. On the other
hand, said mixtures harden & become moldable due to the presence of clays (ball clay
and kaolin). Mixture B, however, did not form a tile body because it did not harden and it
did not become moldable, though it dries. Drying of the mixture is due to the plaster of
paris mold, but because it does not contain clays, it did not harden and it did not become
moldable. It cracks when removing it to the plaster of paris mold. Mixture D contains
feldspar only whose function is to provide strength and hardness to the tile body which is
limited to the fired state of the tile.
Firing Technology
Three firing procedures were done. Different subscripts were used to indicate the
firing procedure done on the tile. The subscript 1 indicates that the tile undergone bisquit
firingproduct procedure. In contrast, the subscript 2 indicates that the tile underwent
glazingglost firingproduct procedure. Nonetheless, the subscript 3 indicates that the
tile go through bisquit firingglazingglost firingproduct procedure. Refer to table
4.2 for the data gathered.
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42
Table 4.2. Firing Technology
Mixture Groups*
No.
of
tiles
fired
No. of
tiles
produced
No. of
tiles that
broke into
fragments
Description
A
A1 4 4 0 no cracks,
no damage
A2 4 4 0
few cracks,
little
damage
A3 4 4 0
few cracks,
little
damage
B
B1
4 4 0
no cracks,
no damage
B2 4 0 4
broke into
fragments,
extensive
damage
B3 4 4 0
few cracks,
little
damage
C
C1 4 4 0 few cracks,
brittle
C2 4 4 0 few cracks,
brittle
C3 4 4 0 no cracks,
no damage
E
E1 4
4 0 no cracks,
no damage
E2 4 4 0
no cracks,
no damage
E3 4 4 0 no cracks,
no damage
*Firing Procedure: 1 - bisquit firingproduct 2 - glazingglost firingproduct
3 - bisquit firingglazingglost firingproduct
As shown in Table 4.2, all the groups except for B2 yields 100% though referring to
the description of each groups, it is noticeable that almost all have little damage. Group
B2 broke into fragments and exhibits extensive damage. This means that it is not feasible
to make tiles with 50% concentration of calcium carbonate and with a glazingglost
firing product procedure. On the other hand, the presence of feldspar provides strength
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43
and hardness to the groups of tiles on the fired state because when the feldspar melts, it
forms a molten glass that causes the particles to cling together. But due to a lesser
concentration of it, qualitatively speaking, the produced tiles do not exhibit much
hardness and strength. The absence of silica sand, however, is substituted by calcium
carbonate which according to studies has the same function as the silica sand. Both silica
sand and calcium carbonate acts as sort of skeleton, reduce firing shrinkage, drying
shrinkage and cracking. But due to its higher concentration in mixtures, A, B and C the
result is the other way around. This means that, higher concentration of calcium
carbonate is not good. Proportions of raw materials should be distributed well.
Test for Physical Properties
The physical properties such as impact strength and porosity of the produced tiles
from oyster shells were tested and compared with commercial ceramic tiles. The
following sections describe the results of said tests.
A. Impact Strength Test
Impact strength is an important property of a ceramic tile on the fired state. It refers to
the ability of ceramic material to bear crushing loads. Impact strength test is done to
measure the capacity of the ceramic tiles produced to bear crushing loads of different
masses. This test is done by dropping three loads of different masses (100g, 200g and
500g) consecutively on the tile 0.68m high.
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44
Table 4.3 shows the result of the impact strength test done on the two
commercial/control tiles F and G which will be used to compare with the experimental
tiles.
Table 4.3 Result of Impact Strength Test for Control Tiles F and G
Table 4.3 shows the impact strength test conducted on the control tiles F and G.
The rating 50.0 indicates that the tile has the greatest impact strength while the rating
10.0 indicates that the tile has the lowest impact strength.
Referring to Table 4.3, it shows that the total mean indicates that control tiles F
and G have the same impact strength. The impact strength result for each control tile will
be used in comparing with the best tile for each mixture using one-way ANOVA but
since control tile F and G have the same impact strength rating, either of the two can be
used.
Table 4.4 shows the result of the impact strength test done on mixture A.
Table 4.4 Result of Impact Strength Test for Mixture A
Tile Trial 1 Trial 2
Mean
Total Rank Loads Loads
1(100g) 2(200g) 3(500g) Mean 1(100g) 2(200g) 3(500g) Mean
F 50.0 50.0 30.0 43.3 50.0 50.0 30.0 43.3 43.3 1.5
G 50.0 50.0 30.0 43.3 50.0 50.0 30.0 43.3 43.3 1.5
Tile Trial 1 Trial 2
Mean
Total Rank Loads Loads
1(100g) 2(200g) 3(500g) Mean 1(100g) 2(200g) 3(500g) Mean
A1 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 3
A2 40.0 30.0 20.0 30.0 30.0 30.0 20.0 26.7 28.4 1
A3 40.0 20.0 20.0 26.7 40.0 20.0 20.0 26.7 26.7 2
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45
Table 4.4 shows the impact strength test conducted on experimental tile A. The
rating 50.0 indicates that the tile has the greatest impact strength while the rating 10.0
indicates that the tile has the lowest impact strength.
Referring to Table 4.4, it shows that the total mean indicates that tile A2 have the
greatest impact strength while tile A1 have the lowest impact strength. For this reason, tile
A2 is selected to be compared with control tiles F and G.
Table 4.5 shows the summary of the one-way ANOVA applied in comparing tile
A2 versus control tiles F or G.
Table 4.5 Summary of one-way ANOVA applied to tile A2 versus tile F or G
Source of
variation
Sum of
Squares
df Mean
Squares
F ratio Interpretation
Between
Groups 223.5 1 223.5
111.8 Significant Within
Group 3.800 2 1.9
Total 227.3 3
As shown in Table 4.5, the F-ratio is more than the critical value, 13.51, then the
null hypothesis, which is, the 2 groups of tiles do not differ in terms of impact strength,
will be rejected. Meaning, tile A2 differ significantly with that of the control tile F or G in
terms of impact strength. Since the mean value of the result of impact strength test done
on experimental tile A2 is less than the mean value of the result of impact test done on
control tile F or G, tile A2 is more fragile compared with the control tiles. This indicates
that it not feasible to make tiles with 40% concentration of calcium carbonate and with a
bisquit firingproduct procedure if the impact strength is the only physical property to
be considered.
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46
Table 4.6 shows the result of the impact strength test done on mixture B.
Table 4.6 Result of Impact Strength Test for Mixture B
Table 4.6 shows the impact strength test conducted on experimental tile B. The
rating 50.0 indicates that the tile has the greatest impact strength while the rating 10.0
indicates that the tile has the lowest impact strength.
Referring to Table 4.6, it shows that the total mean indicates that tile B3 have the
greatest impact strength while tile B1 have the lowest impact strength. For this reason, tile
B3 is selected to be compared with control tiles F and G.
Table 4.7 shows the summary of theone-way ANOVA applied in comparing tile
B3 versus control tiles F or G.
Table 4.7 Summary of one-way ANOVA applied to tile B3 versus tile F or G
Source of
variation
Sum of
Squares
df Mean
Squares
F ratio Interpretation
Between
Groups 43.56 1 43.56
-54.45 Not
Significant Within
Group -1.600 2 -0.8
Total 42.00 3
As shown in Table 4.7, the F-ratio is less than the critical value, 13.51, then the
null hypothesis, which is, the 2 groups of tiles do not differ in terms of impact strength,
will be accepted. Meaning, tile B3 do not differ with that of the control tile F or G in
terms of impact strength. This indicates that it is feasible to make tiles with 50%
concentration of calcium carbonate and with a bisquit firingglazingglost
Tile Trial 1 Trial 2
Mean
Total Rank Loads Loads
1(100g) 2(200g) 3(500g) Mean 1(100g) 2(200g) 3(500g) Mean
B1 40.0 30.0 20.0 30.0 40.0 20.0 20.0 26.7 28.4 2
B3 50.0 40.0 20.0 36.7 50.0 40.0 20.0 36.7 36.7 1
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47
firingproduct procedure if the impact strength is the only physical property to be
considered.
Table 4.8 shows the result of the impact strength test conducted on experimental
tile C.
Table 4.8 Result of Impact Strength Test for Mixture C
Table 4.8 shows the impact strength test conducted on experimental tile C. The
rating 50.0 indicates that the tile has the greatest impact strength while the rating 10.0
indicates that the tile has the lowest impact strength.
Referring to Table 4.8, it shows that the total mean indicates that tile C3 have the
greatest impact strength while tile C1 have the lowest impact strength. For this reason, tile
C3 is selected to be compared with control tiles F and G.
Table 4.9 shows the summary of the one-way ANOVA applied in comparing tile
C3 versus control tiles F or G.
Table 4.9 Summary of one-way ANOVA applied to tile C3 versus tile F or G
Source of
variation
Sum of
Squares
df Mean
Squares
F ratio Interpretation
Between
Groups 24.50 1 24.50
12.89 Not
Significant Within
Group 3.800 2 1.900
Total 28.30 3
As shown in Table 4.9 the F-ratio is less than the critical value, 13.51, then the
null hypothesis, which is, the 2 groups of tiles do not differ in terms of impact strength,
Tile Trial 1 Trial 2 Mean
Total Rank Loads Loads
1(100g) 2(200g) 3(500g) Mean 1(100g) 2(200g) 3(500g) Mean
C1 40.0 20.0 20.0 26.7 40.0 20.0 20.0 26.7 26.7 3
C2 40.0 40.0 20.0 33.3 40.0 40.0 20.0 33.3 33.3 2
C3 50.0 50.0 20.0 40.0 50.0 40.0 20.0 36.7 38.4 1
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48
will be accepted. Meaning, tile C3 is comparable to control tile F or G in terms of impact
strength. This indicates that it is feasible to make tiles with 60% concentration of calcium
carbonate and with a bisquit firingglazingglost firingproduct procedure if the
impact strength is the only physical property to be considered.
Table 4.10 shows the result of the impact strength test conducted on experimental
tile E.
Table 4.10 Result of Impact Strength Test for Mixture E
Table 4.10 shows the impact strength test conducted on experimental tile E. The
rating 50.0 indicates that the tile has the greatest impact strength while the rating 10.0
indicates that the tile has the lowest impact strength.
Referring to Table 4.10, it shows that the total mean indicates that tile E1 have the
greatest impact strength while tile E2 have the lowest impact strength. For this reason, tile
E1 is selected to be compared with control tiles F and G.
Table 4.11 shows the summary of the one-way ANOVA applied in comparing tile
E1 versus control tiles F or G.
Table 4.11 Summary of one-way ANOVA applied to tile E1 versus tile F or G
Source of
variation
Sum of
Squares
df Mean
Squares
F ratio Interpretation
Between
Groups 223.5 1 223.5
111.8 Significant Within
Group 3.800 2 1.900
Total 227.0 3
Tile Trial 1 Trial 2
Mean
Total Rank Loads Loads
1(100g) 2(200g) 3(500g) Mean 1(100g) 2(200g) 3(500g) Mean
E1 40.0 30.0 20.0 30.0 40.0 20.0 20.0 26.7 28.4 1
E2 20.0 20.0 20.0 20.0 20.0 20.0 10.0 16.6 18.3 3
E3 40.0 20.0 10.0 23.3 40.0 20.0 10.0 23.3 23.3 2
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49
As shown in Table 4.11, the F-ratio is more than the critical value, 13.51, then the
null hypothesis, which is, the 2 groups of tiles do not differ in terms of impact strength,
will be rejected. Meaning, tile E1 differ significantly with that of the control tile F or G in
terms of impact strength. Since the mean value of the result of impact test done on
experimental tile E1 is less than the mean value of the result of impact strength test done
on control tile F or G, tile E1 is more fragile compared with the control tiles. This
indicates that it not feasible to make tiles with 0% concentration of calcium carbonate or
silica sand and with a bisquit firingproduct procedure if the impact strength is the only
physical property to be considered.
In general, groups B3 and C3 are the tiles comparable with control tiles F or G in
terms of impact strength.
B. Porosity Test
Porosity is an important physical property of a ceramic tile on the fired state. It
refers to the penetration of liquids and vapors through the material that usually causes
structural damage. The porosity test is conducted to determine how much liquid the
produced ceramic tile will absorb in standard period of time. It is done by measuring the
unsaturated mass of the tile, the liquid-dipped mass of the tile and the saturated mass of
the tile. The resulting masses were then substituted to the equation for percent apparent
porosity.
Table 4.12 shows the result of the porosity test done on the control tiles F and G.
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50
Table 4.12 Result of porosity test (in percent apparent porosity, %Pa) for control tiles F
and G
Tile Trial 1 Trial 2 Mean
Rank %Pa (%) %Pa (%) (%)
F 48.57 40.00 44.29 1
G 45.46 46.73 46.15 2
Table 4.12 shows the porosity test done on control tiles F and G. It illustrates that
the lesser the percent apparent porosity, the lesser is its susceptibility to be penetrated by
liquids, the better.
As shown in Table 4.12 control tile F has the least percent apparent porosity,
meaning it is less susceptible to be penetrated by liquids while control tile G has larger
percent apparent porosity, meaning it is more susceptible to be penetrated by liquids and
vapors. For this reason, control tile F is selected to be compared with the experimental
tiles.
Table 4.13 shows the results of the porosity test for mixture A.
Table 4.13 Result of porosity test (in percent apparent porosity, %Pa) for mixture A
Tile Trial 1 Trial 2 Mean
Rank %Pa (%) %Pa (%) (%)
A1 46.00 45.82 45.91 2
A2 39.90 40.46 40.18 1
A3 47.47 47.74 47.61 3
Table 4.13 shows the porosity test for mixture A. It illustrates that the lesser the
percent apparent porosity, the lesser is its susceptibility to be penetrated by liquids, the
better.
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51
Referring to Table 4.13, it shows that tile A2 has the least percent apparent
porosity, meaning it is less susceptible to be penetrated by liquids while tile A3 have the
largest percent apparent porosity, meaning it is more susceptible to be penetrated by
liquids and vapors. For this reason, tile A2 is selected to be compared with control tile F.
Table 4.14 shows the one-way ANOVA applied in comparing tile A2 versus
control tile F.
Table 4.14 Summary of one-way ANOVA applied to tile A2 versus tile F
Source of
variation
Sum of
Squares
df Mean
Squares
F ratio Interpretation
Between
Groups 19.38 1 19.38
1.053 Not
Significant Within
Group 36.82 2 18.41
Total 56.20 3
As shown in Table 4.14, the F-ratio is less than the critical value, 13.51, then the
null hypothesis, which is, the 2 groups of tiles do not differ in terms of porosity, will be
accepted. Meaning, tile A2 is comparable with control tile F in terms of porosity. This
indicates that it is feasible to make tiles with 40% concentration of calcium carbonate and
with a bisquit firingproduct procedure if porosity is the only physical property to be
considered.
Table 4.15 shows the results of the porosity test for mixture B.
Table 4.15 Result of porosity test (in percent apparent porosity, %Pa) for mixture B
Tile Trial 1 Trial 2 Mean
Rank %Pa (%) %Pa (%) (%)
B1 47.54 48.96 48.25 1
B3 49.61 47.29 48.41 2
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52
Table 4.13 shows the porosity test for mixture B. It illustrates that the lesser the
percent apparent porosity, the lesser is its susceptibility to be penetrated by liquids, the
better.
Referring to Table 4.13, tile B1 has the least percent apparent porosity, meaning it
is less susceptible to be penetrated by liquids while tile B3 have larger percent apparent
porosity, meaning it is more susceptible to be penetrated by liquids and vapors. For this
reason, tile B1 is selected to be compared with control tile F.
Table 4.16 shows the summary of the one-way ANOVA applied in comparing tile
B1 versus control tile F.
Table 4.16 Summary of one-way ANOVA applied to tile B1 versus tile F
Source of
variation
Sum of
Squares
df Mean
Squares
F ratio Interpretation
Between
Groups 12.94 1 12.94
0.6890 Not
Significant Within
Group 37.56 2 18.78
Total 50.50 3
As shown in Table 4.16, the F-ratio is less than the critical value, 13.51, then the
null hypothesis, which is, the 2 groups of tiles do not differ in terms of porosity, will be
accepted. Meaning, tile A2 is comparable with control tile F in terms of porosity. This
indicates that it is feasible to make tiles with 50% concentration of calcium carbonate and
with a glazingglost firingproduct procedure if porosity is the only physical property
to be considered.
Table 4.17 shows the results of the porosity test for mixture C.
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53
Table 4.17 Result of porosity test (in percent apparent porosity, %Pa) for mixture C
Tile Trial 1 Trial 2 Mean
Rank %Pa (%) %Pa (%) (%)
C1 63.56 64.60 64.08 3
C2 64.06 64.02 64.04 2
C3 59.92 59.47 59.70 1
Table 4.17 shows the porosity test for mixture C. It illustrates that the lesser the
percent apparent porosity, the lesser is its susceptibility to be penetrated by liquids, the
better.
Referring to Table 4.17, tile C3 has the least percent apparent porosity, meaning it
is less susceptible to be penetrated by liquids while tile C1 have larger percent apparent
porosity, meaning it is more susceptible to be penetrated by liquids and vapors. For this
reason, tile C3 is selected to be compared with control tile F.
Table 4.18 shows the summary of the one-way ANOVA applied in comparing tile
C3 versus control tile F.
Table 4.18 Summary of one-way ANOVA applied to tile C3 versus tile F
Source of
variation
Sum of
Squares
df Mean
Squares
F ratio Interpretation
Between
Groups 234.5 1 234.5
13.21 Not
Significant Within
Group 35.50 2 17.75
Total 270.0 3
As shown in Table 4.18, the F-ratio is less than the critical value, 13.51, then the
null hypothesis, which is, the 2 groups of tiles do not differ in terms of porosity, will be
accepted. Meaning, tile C3 is comparable with control tile F in terms of porosity. This
indicates that it is somewhat feasible to make tiles with 60% concentration of calcium
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54
carbonate and with a bisquit firingglazingglost firingproduct procedure if porosity
is the only physical property to be considered.
Table 4.19 shows the results of the porosity test for mixture E.
Table 4.19 Result of porosity test (in percent apparent porosity, %Pa) for mixture E
Tile Trial 1 Trial 2 Mean
Rank %Pa (%) %Pa (%) (%)
E1 29.32 23.26 26.29 1
E2 32.42 30.02 31.22 3
E3 24.44 23.33 23.89 2
Table 4.19 shows the porosity test for mixture E. It illustrates that the lesser the
percent apparent porosity, the lesser is its susceptibility to be penetrated by liquids, the
better.
Referring to Table 4.19, tile E1 has the least percent apparent porosity, meaning it
is less susceptible to be penetrated by liquids while tile E2 have the largest percent
apparent porosity, meaning it is more susceptible to be penetrated by liquids and vapors.
For this reason, tile E1 is selected to be compared with control tile F.
Table 4.20 shows the summary of the one-way ANOVA applied in comparing tile
E1 versus control tile F.
Table 4.20 Summary of one-way ANOVA applied to tile E1 versus tile F
Source of
variation
Sum of
Squares
df Mean
Squares
F ratio Interpretation
Between
Groups 320.3 1 320.3
546.1 Significant Within
Group 1.173 2 0.5865
Total 375.6 3
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55
As shown in Table 4.20, the F-ratio is more than the critical value, 13.51, then the
null hypothesis, which is, the 2 groups of tiles do not differ in terms of porosity, will be
rejected. Meaning, tile E1 differs significantly with control tile F in terms of porosity. But
for this sample, E1 has lesser percent apparent porosity than control tile F. Meaning, tile
E1 is less susceptible to the penetration of liquids than control tile F. This indicates that it
is feasible to make tiles with 0% concentration of calcium carbonate or silica sand and
with a bisquit firingproduct procedure if porosity is the only physical property to be
considered. The hardened clays after firing that make this group resistant to action of
liquids and vapors. But because it does not contain calcium carbonate or silica sand, the
tile is fragile.
In general, tiles A2 B1 and C3 are the tiles comparable with control tile F in terms
of porosity.
Table 4.21 shows the summary of results for the best tiles produced according to
the one-way ANOVA used.
Table 4.21 Summary of results for the best tiles produced
Tile* % Oyster Shells Impact Strength Porosity Decision
A2 40 Not Feasible Feasible Not Feasible
B1 50 Not Feasible Feasible Not Feasible
B3 50 Feasible Not Feasible Not Feasible
C3 60 Feasible Feasible Feasible *Firing Procedure: 1 - bisquit firingproduct 2 - glazingglost firingproduct
3 - bisquit firingglazingglost firingproduct
As shown in Table 4.21, it suggests that tile C3 is the most feasible experimental
tile because it is feasible in both impact strength and porosity test done. This means that it
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56
is feasible to make tile with 60% concentration of calcium carbonate and with a bisquit
firingglazingglost firingproduct procedure.
However, as shown in Table 4.21, tiles A2, B1 and B3 are feasible in one physical
property only that is why the decision for its acceptance is not feasible. It is very
important that the produced tile pass all the tests for physical properties to achieve
quality.
It was also observed in the study that the lesser the calcium carbonate added to the
tile, the smaller the porosity. The lesser the percent apparent porosity means that the
susceptibility of the tile to absorb liquid or vapor is less. It is because calcium oxide
(from fired calcium carbonate) easily absorbs liquids like water to form hydroxides.
On the other hand, the greater the amount of calcium carbonate added to the tile,
the greater is the impact strength. The greater the impact strength means that the ability of
the tile to bear crushing load is better. It is because calcium carbonate reduces the drying
shrinkage, prevents cracking of the piece and act as a sort of skeleton to hold the shape of
the piece.
Table 4.22 shows the rough estimate of the costs of chemicals and equipment
utilized in the study.
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57
Table 4.22 Cost of materials utilized in the study
Material Quantity Unit Price Price
Ball clay 1.00 kg P 15.00/kg P 15.00
Feldspar 4.20 kg 12.00/kg 50.40
Kaolin 2.00 kg 28.85/kg 47.70
Plaster of paris 18.0 kg 18.75/kg 337.50
Calcium carbonate 0.48 kg 21.50/kg 10.32
Sodium silicate 0.15 L 45.00/L 6.75
CMC 0.25 kg 174.00/kg 43.50
Firing Machine 1 pc 500.00/day 500.00
Total P 1,011.17
Referring at Table 4.22, it shows that the total cost of the study amounted to
roughly one thousand eleven and 17/100 pesos (P1,011.17). This amount was utilized in
the production of 60 pieces of tiles. Dividing the amount used in the study with the
number of tiles will give out 16.85. Meaning, if the tiles were to be sold, its unit price
would be P16.85/piece which is higher than the price of the commercial tiles which is
P12.50/piece. The difference would be P4.35.
The unit price may seem expensive but it should also be considered that the
plaster of paris mold can be used over and over again and the firing machine could fire
more than 60 tiles a day.
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58
Chapter 5
CONCLUSION AND RECOMMENDATIONS
The main objective of the study is to investigate the feasibility of the Crassostrea
iredalei (oyster) shell as base for ceramic tile making. Specifically, it aimed to: (a) utilize
Crassostrea iredalei (oyster) shells as substitute to silicon dioxide (silica sand) in ceramic
tile making; (b) test the physical properties like impact strength and porosity of the
produced ceramic tiles; and (c) compare the ceramic tile made of Crassostrea iredalei
(oyster) shells to commercially available ones such as the Mariwasa Ceramic Tiles and
Floor Center Ceramic Tiles in terms of impact strength and porosity via One-Way
ANOVA.
Based on the statistical analysis, it was found out that utilizing Crassostrea
iredalei (oyster) shells as substitute to silicon dioxide (silica sand) in ceramic tile making
at a 60% substitution and with a bisquit firingglazingglost firingproduct firing
procedure is feasible. The produced tile is comparable with the commercial tiles like
Mariwasa Ceramic Tiles and Floor Center Ceramic Tiles in terms of impact strength
and porosity. The other percent substitution of calcium carbonate including the firing
procedure done is not as effective ad the 60% substitution.
To further enhance or modify this research study, the researchers throw the
following recommendations:
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59
1) Utilize other test for the physical properties of the best tile produced.
2) The use of other tile body forming method like the dust press method or
the spray drying method;
3) Reformulation of the proportions of the calcium carbonate, ball clay,
feldspar and kaolin used.
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60
BIBLIOGRAPHY
1 JEFE (2000). Downloaded on August 10, 2006 from
http://www.jefo.ca/fiches_anglais/oyster_shells.html
2 Britannica, 1978
3 Encyclopedia Britannica, Vol. 4, 1988
4 Jamaica Export Trading Company. Downloaded on October 24, 2006 from
http://www.exportjamaica.org/jetco/click.htm
5 University of Florida News (2004). Downloaded on August 10, 2006 from
http://www.napa.ufl.edu/2004news/oystertip.htm
6 Rx List (2005). Downloaded on August 10, 2006 from http://www.rxlist.com/drugs/drug-
20939Calcium+Oyster+Shell+Oral.aspx?drugid=20939&drugname=Calcium+Oyster+Shell+Oral
7 Planet Natural (2004). Downloaded on August 10, 2006 from
http://www.planetnatural.com/site/oyster-shell-lime.html
8 The World Book Encyclopedia, Vol. 16, 1958
9 Training Manual on Ceramic Artware Production published by the Rural Technology &
Information Division, Industrial Technology Development Institute, Department of
Science and Technology.
10 The Tile Doctor (2003). Downloaded on August 10, 2006 from
http://www.thetiledoctor.com/tile_manufac.cfm
11 Alibaba.com (1999). Downloaded on October 5, 2006 from
http://www.alibaba.com/catalog/11336587/Water_Washed_Lavigated_China_Clay_Kaol
in.html
12 (October 2001). China Raw Ball Clay QY-03 Chemical Analysis. Quezon City: Central
Ceramic Center.
13Wikipedia (2006). Downloaded on October 24, 2006 from
http://en.wikipedia.org/wiki/Silica
14 Production of Ceramic Artwares published by the Rural Technology & Information
Division, Industrial Technology Development Institute, Department of Science and
Technology.
15 Ceramic-tile.com (2003). Downloaded on August 10, 2006 from http://www.ceramic-
tile.com/class.cfm
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61
16 Isidro, Reinier Augustus and Sheryll R. Jamito. 2006. Janitor Fishs Skin Reinforced
Concrete Blocks. Manila: Philippine Normal University Research Paper.
17 Camara, Paolo, Janssen Canicula, Rex Capuno, Don dela Cruz and Christopher
Sanguyo. 2001. Feasibility of Foam Polystyrene and Powdered Talaba Shells as Tiles.
Quezon City, Philippines: Philippine Science High School Research Paper.
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62
APPENDIX A
Raw Data and Computations for Impact Strength Test
Impact Strength Test
Results of One-Way ANOVA
Group A
X = 143.3
Do the 2 groups of tiles differ in terms of impact strength?
Step 1: Ho = M1 = M2= the 2 groups of tiles do not differ in terms of impact strength
H1 = M1 M2 = the 2 groups of tiles do differ in terms of impact strength
Step 2: .05 level
Step 3: dfb = k-1 2-1 = 1
dfw = N-k = 4-2 = 2
Tile
Trial 1 Trial 2 Mean
Total Loads Loads
1(100g) 2(200g) 3(500g) Mean 1(100g) 2(200g) 3(500g) Mean
A1 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0
A2 40.0 30.0 20.0 30.0 30.0 30.0 20.0 26.7 28.4
A3 40.0 20.0 20.0 26.7 40.0 20.0 20.0 26.7 26.7
B1 40.0 30.0 20.0 30.0 40.0 20.0 20.0 26.7 56.7
B3 50.0 40.0 20.0 36.7 50.0 40.0 20.0 36.7 36.7
C1 40.0 20.0 20.0 26.7 40.0 20.0 20.0 26.7 26.7
C2 40.0 40.0 20.0 33.3 40.0 40.0 20.0 33.3 33.3
C3 50.0 50.0 20.0 40.0 50.0 40.0 20.0 36.7 38.4
E1 40.0 30.0 20.0 30.0 40.0 20.0 20.0 26.7 28.4
E2 20.0 20.0 20.0 20.0 20.0 20.0 10.0 16.6 18.3
E3 40.0 20.0 10.0 23.3 40.0 20.0 10.0 23.3 23.3
F 50.0 50.0 30.0 43.3 50.0 50.0 30.0 43.3 43.3
G 50.0 50.0 30.0 43.3 50.0 50.0 30.0 43.3 43.3
Trial A2 F/G
1 30.0 43.3
2 26.7 43.3
56.7 86.6
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63
Step 4: DR: if F 13.51 reject Ho DR: if F < 13.51 accept Ho
X2 = 5361
Step 5: (5.1) total sum of squares
SSt = X2
_ ( X)2
N
= 5361 (143.3) 2
4
= 227.3
(5.2) sum of squares for between groups
SSb = ( X)2 + ( X)
2 - ( X)
2
n1 n2 N
= (30.0)2
+ (26.7) 2
+ (43.3)2
+ (43.3)2
- (143.3)
2
2 2 2 2 4
= 223.5
(5.3) sum of squares for w/in groups
SSw = SSt SSb = 227.3 223.5 = 3.8
(5.4) mean squares
* for between groups * for w/in groups
MSb = SSb MSw = SSw K-1 (2-1) N-k (4-2)
= 223.5 = 3.8
1 2
= 223.5 = 1.9
(5.5) F ratio
F = MSb
MSw
= 223.5
1.9
= 111.8
Trial A2 F/G
1 900 1874
2 713 1874
1613 3748
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64
Step 6: Decision: Reject Ho
Step 7: The 2 groups of tiles differ in terms of impact strength
Summary Table
Group B
Trial B3 F/G
1 36.7 43.3
2 36.7 43.3
73.4 86.6
X=160.0
Do the 2 groups of tiles differ in terms of impact strength?
Step 1: Ho = M1 = M2= the 2 groups of tiles do not differ in terms of impact strength
H1 = M1 M2 = the 2 groups of tiles do differ in terms of impact strength
Step 2: .05 level
Step 3: dfb = k-1 2-1 = 1
dfw = N-k = 4-2 = 2
Step 4: DR: if F 13.51 reject Ho DR: if F < 13.51 accept Ho
Trial B3 F/G
1 1347 1874
2 1347 1874
2694 3748
x2 = 6442
Source of
variation
Sum of
Squares
df Mean
Squares
F ratio Interpretation
Between
Groups 223.5 1 223.5
111.8 Significant Within
Group 3.800 2 1.9
Total 227.3 3
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65
Step 5: (5.1) total sum of squares
SSt = X2
_ ( X)2
N
= 6442 (160) 2
2
= 42
(5.2) sum of squares for between groups
SSb = ( X)2 + ( X)
2 - ( X)
2
n1 n2 N
= (36.7)2
+ (36.76) 2
+ (43.3)2
+ (43.3)2
- (160)
2
2 2 2 2 4
= 223.5
(5.3) sum of squares for w/in groups
SSw = SSt SSb = 42 43.56 = - 1.6
(5.4) mean squares
* for between groups * for w/in groups
MSb = SSb MSw = SSw K-1 (2-1) N-k (6-2)
= 10.9 = 28.7
2 6
= 43.56 = - 0.8
(5.5) F ratio
F = MSb
MSw
= 43.56
-0.8
= - 54.45
Step 6: Decision: Accept Ho
Step 7: The 2 groups of tiles do not differ in terms of impact strength
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66
Summary Table
Source of
variation
Sum of
Squares
df Mean
Squares
F ratio Interpretation
Between
Groups 43.56 1 43.56
-54.45 Not
Significant Within
Group -1.600 2 -0.8
Total 42.00 3
Group C
Trial C3 F/G
1 40.0 43.3
2 36.7 43.3
76.7 86.6
X=163.3
Do the 2 groups of tiles differ in terms of impact strength?
Step 1: Ho = M1 = M2= M3 = the 2 groups of tiles do not differ in terms of impact
strength
H1 = M1 M2 M3 = the 2 groups of tiles do differ in terms of impact strength
Step 2: .05 level
Step 3: dfb = k-1 2-1 = 1
dfw = N-k = 4-2 = 2
Step 4: DR: if F 13.51 reject Ho DR: if F < 13.51 accept Ho
Trial C3 F/G
1 1600 1874
2 1347 1874
2947 3748
x2 = 6695
Step 5: (5.1) total sum of squares
SSt = X2
_ ( X)2
N
= 6695 (163.3) 2
4
= 28.3
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67
(5.2) sum of squares for between groups
SSb = ( X)2 + ( X)
2 - ( X)
2
n1 n2 N
= (40.0)2
+ (36.7) 2
+ (43.3)2
+ (43.3)2
- (163.3)
2
2 2 2 2 4
= 223.5
(5.3) sum of squares for w/in groups
SSw = SSt SSb =28.3 24.5 = 3.8
(5.4) mean squares
* for between groups * for w/in groups
MSb = SSb MSw = SSw K-1 (2-1) N-k (4-2)
= 24.5 = 3.8
1 2
= 24.5 = 1.9
(5.5) F ratio
F = MSb
MSw
= 24.5
1.9
= 12.89
Step 6: Decision: Accept Ho
Step 7: The 2 groups of tiles do not differ in terms of impact strength
Summary Table
Source of
variation
Sum of
Squares
df Mean
Squares
F ratio Interpretation
Between
Groups 24.50 1 24.50
12.89 Not
Significant Within
Group 3.800 2 1.900
Total 28.30 3
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68
Group E
Trial E1 F/G
1 40.0 43.3
2 36.7 43.3
76.7 86.6
X=143.3
Do the 2 groups of tiles differ in terms of impact strength?
Step 1: Ho = M1 = M2= the 2 groups of tiles do not differ in terms of impact strength
H1 = M1 M2 = the 2 groups of tiles do differ in terms of impact strength
Step 2: .05 level
Step 3: dfb = k-1 2-1 = 1
dfw = N-k = 4-2 = 2
Step 4: DR: if F 13.51 reject Ho DR: if F < 13.51 accept Ho
Trial E1 F/G
1 900 1874
2 713 1874
1613 3748
x2 = 5361
Step 5: (5.1) total sum of squares
SSt = X2
_ ( X)2
N
= 5361 (143.3) 2
4
= 227.3
(5.2) sum of squares for between groups
SSb = ( X)2 + ( X)
2 - ( X)
2
n1 n2 N
= (30.0)2
+ (26.7) 2
+ (43.3)2
+ (43.3)2
- (143.3)
2
2 2 2 2 4
= 223.5
(5.3) sum of squares for w/in groups
SSw = SSt SSb =28.3 24.5 = 3.8
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69
(5.
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