Assessment of particulates matrix ratio and its influence on mechanical properties of granite particulates

1. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
INTERNATIONAL JOURNAL OF MECHANICAL ENGINEERING
17 – 19, July 2014, Mysore, Karnataka, India
AND TECHNOLOGY (IJMET)
ISSN 0976 – 6340 (Print)
ISSN 0976 – 6359 (Online)
Volume 5, Issue 9, September (2014), pp. 266-270
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IJMET
© I A E M E
ASSESSMENT OF PARTICULATES MATRIX RATIO AND ITS INFLUENCE
266
ON MECHANICAL PROPERTIES OF GRANITE PARTICULATES
REINFORCED EPOXY COMPOSITE
Joel Antony D’Mello[1], S. S. Balakrishna[2]
[1] M Tech Scholar, Department of Mechanical Engineering, Sahyadri College of Engineering Management, Karnataka,
India
[2] Professor Head, Department of Mechanical Engineering, Sahyadri College of Engineering Management,
Karnataka, India
ABSTRACT
Influence of epoxy content and granular size of granite in processing of prepared PMC using epoxy polymeric
matrix reinforced with granite particulates has been investigated. The percentage of epoxy content, granite granular ratio
and Compressive load are the parameters used for the study. An L27 orthogonal array and ANOVA were used to
emphasize the contribution of individual parameters. The test samples subjected to compression test recorded a high
compressive strength of 116 MPa for 20 percentage of weight epoxy and 50-50 granite particulate ratio.
Keywords: ANOVA, Compression, Compressive Strength, Epoxy, Granite.
1. INTRODUCTION
The use of fiber reinforced composite materials has found growing importance in every field of engineering due
to its overwhelming advantages over conventional materials. However the presence of two or more dissimilar phases
indicts the composite material into encountering prominent challenges during material characterization. The testing
processes involved in fiber reinforced composite materials are not the same as in the case of conventional metals due to
their stress and load handling capacity. Therefore, testing of composite materials usually incorporates conditions and
requirements that are not encountered in conventional metal testing. Here an alternative material embedded with high
stiffness and damping is used for making machine tool structure. Epoxy granite is one such material that exhibits good
material properties like high stiffness, damping and coefficient of thermal expansion. Thus the present study involves
analyzing the material properties of epoxy granite experimentally.
The compressive strength is largely being considered as an advertence property for structural applications and is
popularly called to be known as material strength. The optimization of compressive strength and the understanding its
relationship with the processing variables may be accomplished by applying statistical techniques such as design of
experiments (DOE). The main advantage of applying DOE is the possibility of assigning a great number of variables and
studying interactions between them. The number of total experimental runs (N) or experimental observations are
determined by the relation N = mk, where m defines the number of levels of each variable under investigation and k,
number of variables under investigation.
Antonio et al [1] conducted compression tests on epoxy polymeric matrix reinforced with particulate ceramic
granite. Experiments were planned and executed according to the Factorial design technique using two variables at two
levels. The obtained cylindrical samples were submitted to compressive strength tests and the results showed a maximum

2. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
resistance of 114.23 MPa at 20 (%) weight epoxy. Lee et al [2] studied the slides of high speed CNC milling machines
designed with fiber reinforced composite materials to overcome high speed operations. These fabricated composite
structures reduced the weight of the vertical and horizontal slides considerably by 34% and 26% respectively, and
increased damping by 1.5–5.7 times without sacrificing stiffness. Sulaiman et al [3] studied the effect of hardener on
mechanical properties of carbon reinforced phenolic resin composites experimentally. The results delineated that
composite with 15% hardener content show an increase in flexural strength, tensile strength and hardness. The ultimate
tensile strength (UTS), flexural strength and hardness for 15% hardener were recorded to be 411.9 MPa, 51.7 MPa and
85.4 HRR respectively. Rama Krishna et al [4] concluded that granite epoxy composite materials are resistant to acetic
acid, concentrated hydrochloric acid and sodium hydroxide. Flaminio et al [5] studied damping effect on Granite-epoxy
which was found to be significantly higher than the gray cast iron. For the same volume of composite materials with
weight fractions of about 80% of granite and 20% of epoxy, damping properties showed approximately three times
increment compared to gray cast iron. Selvakumar et al [6] concluded that for the same stiffness, the epoxy granite
structure offers considerable weight reduction with very good damping characteristics. Ravindra et al [7] studies
revealed that toughened epoxy resin composites with Hydroxyl terminated polyurethane (HTPU) in different proportions
enhance the properties compared to neat matrix. The tensile and flexural strength of granite powder filled 1% HTPU
toughened epoxy composites showed a superior result compared to those of granite powder filled epoxy composites.
Jung et al [8] conducted studies to improve the damping characteristics of a spindle cover for high speed machine tools;
the cover was reinforced carbon fiber epoxy composite. The tests revealed damping improvement of composite hybrid
spindle over a wide frequency range. Based on the literature cited above the present work is one such attempt to analyze
the material characterization of Granite epoxy composites by compression tests.
267
2. EXPERIMENTAL PROCEDURE
2.1 Materials
The matrix implemented was epoxy with a standard grade of L12 (3202) since it provides good resistance to
alkalis and good adhesive properties and a K6 hardener was used. The reinforcement employed was Ceramic Granite,
crushed and sieved to different granular sizes to accumulate the study. Two different granular sizes of 75-105 micro
meter and 300-424 micro meter were selected and experimentation was conducted for a 50:50, 60:40 and 70:30 granule
mixtures. The sample preparation was planned by first adding hardener to epoxy resin in ratio of 1:10 followed by
mixing with granite to promote heterogeneity in compression samples. The specimens used in the study were Teflon
molded. The mould cavities followed ASTM 695 and L/D ratio was fixed to 2. The obtained specimens remained in
cavity for 24 hours followed by 4 hours of heat curing at 60ºC initially and then cured for 200 hours at room temperature.
2.2 Plan of Experiments
The Taguchi technique for the design of experiments is used for the plan of experiments with three factors at
three levels. The design parameters considered were weight percentage of Epoxy and granite granular ratio. The factors
that are considered in this experiment along with their levels are as shown in Table 1. The experiment consists of 27 tests
corresponding to the number of rows and columns assigned with the parameters. The first column is assigned to weight
percentage of epoxy content and second column to granite granular ratio. A standard L27 orthogonal array was chosen
with twenty seven rows and two columns as presented in Table 2. The experiments were conducted as per the orthogonal
array with level of parameters given in each row. The test results were subjected to the analysis of variance.
Table 1: Process parameters and their values
Level Epoxy Wt%
Granite Granule
Mix
1 15 50-50
2 20 60-40
3 25 70-30
2.3 Experimentation
Compression tests were carried on the specimen using FIE make Universal Testing Machine of 40Ton capacity,
establishing a load rate of 1.2kN/min. The specimens prepared as per ASTM were subjected to compression at steady
state loading till fracture to observe the maximum compressive strength. The compressive strength was recorded through
an FIE software interfaced to the UTM. The material characterization is measured as a function of Epoxy content and
Granular grit ratio.

3. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
Epoxy Weight
%
15 50-50 76
15 50-50 76
15 50-50 73
15 60-40 90
15 60-40 93
15 60-40 89
15 70-30 73
15 70-30 100
15 70-30 99
20 50-50 112
20 50-50 105
20 50-50 116
20 60-40 112
20 60-40 109
20 60-40 107
20 70-30 110
20 70-30 102
20 70-30 99
25 50-50 105
25 50-50 98
25 50-50 105
25 60-40 93
25 60-40 105
25 60-40 96
25 70-30 103
25 70-30 106
25 70-30 99
268
3. RESULTS AND DISCUSSIONS
The material characterization and behavior of the granite–epoxy composites has been studied as a function of
Epoxy and granite weight content. The results obtained as per the L27 orthogonal array are shown in the Table 3.
3.1 Analysis of Variance
The objective of employing analysis of variance (ANOVA) was to inspect the parametric significance on the
compressive property of the composite. The results of the experimental analysis are shown in Table 3. The maximum
compressive strength observed during the test was recorded to be 116 MPa and this was observed for an epoxy weight
percentage of 20 and 50:50 granite granular grit ratio. These results are subjected to Analysis of variance as shown in
Table 4 and studied accordingly. The last column of the tables shows the percentage contribution of each factor on the
total variation indicating the influence of the parameter on the compression.
Table 2: Orthogonal array L27 of Taguchi Table 3: Experimental Results
SI No
Epoxy
Content
Granite
Granule
Ratio
1 1 1
2 1 1
3 1 1
4 1 2
5 1 2
6 1 2
7 1 3
8 1 3
9 1 3
10 2 1
11 2 1
12 2 1
13 2 2
14 2 2
15 2 2
16 2 3
17 2 3
18 2 3
19 3 1
20 3 1
21 3 1
22 3 2
23 3 2
24 3 2
25 3 3
26 3 3
27 3 3
Granite
Granule Mix
Compressive
Strength MPa
Considering the Anova results for compression tests shown in Table 4; it highlighted statistically that variable
epoxy content was significant having a probability of approximately 63%, while granite granulation did not exhibit a
significant outcome on the compressive strength showing a diminished probability of 1.3%. Similarly the interaction
between epoxy and granite granules showed a impending probability of approximately 15%. It is remarkable to scrutinize
that at an epoxy weight percentage of 20, exhibited highest compressive strength of 116 MPa compared to 15 percent and
25 percent in weight. To highlight during fabrication of specimen 15 % by weight of epoxy and remaining percentage by
weight of granite granule mix, observations were made that small quantity of epoxy was not able to exhibit complete wet
ability which created difficulties in manual fabrication. For more content of epoxy, other 25% by weight showed
sedimentation of granite granules took place in the mould cavity during curing process.

4. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
Fig.1: Experimental results for Variation of Compressive strength with respect to Epoxy weight percentage for
different granular ratios
Table 4: ANOVA for Compression tests of Granite Epoxy
Source DF SS MS F P P%
269
Epoxy
Content_1
2 2404.96 1202.48 28.55 0 63.32
Granule Grit
Ratio
2 52.52 26.26 0.62 0.547 1.3
Interaction 4 570.59 142.65 3.39 0.031 15
Error 18 758 42.11 20
Total 26 3786.07
Main Effects Plot for COMPRESSIVE STRENGTH N/sq mm
1 2 3
110
105
100
95
90
85
80
1 2 3
EPOXY CONTENT
Mean
FIBER GRIT RATIO
Data Means
Probability Plot of COMPRESSIVE STRENGTH N/sq mm
60 70 80 90 100 110 120 130 140
99
95
90
80
70
60
50
40
30
20
10
5
1
COMPRESSIVE STRENGTH N/sq mm
Percent
Mean 98.11
StDev 11.85
N 27
AD 0.895
P-Value 0.019
Normal - 95% CI
Fig. 2: Variation of Compression strength Fig. 3: Normal probability plot of
with respect to Epoxy and Grit ratio Compressive strength
1 2 3
110
100
90
80
1 2 3
110
100
90
80
EPOXY CONTENT
FIBER GRIT RATIO
EPOXY
CONTENT
1
2
3
FIBER
GRIT
RATIO
1
2
3
Interaction Plot for COMPRESSIVE STRENGTH N/sq mm
Data Means
Fig. 4: Interaction plots of variables

5. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
270
The interaction effect plotted in Fig. 4 monitors, when change in epoxy from 15% to 20% by weight exhibits a
positive slope highlighting its contribution elevating the compressive strength, but a negative slope is obtained when
epoxy content increased from 20% to 25% by weight. Similarly granular ratio affected very little towards the
improvement of compressive strength.
CONCLUSION
Taguchi’s robust design method is used to study the compressive behavior of the granite – epoxy composite and
the following conclusions were drawn from this study:
It is observed that the maximum compressive strength of 116 MPa for 20% weight epoxy and 50% small and 50%
large granite grit ratio. The results obtained were found to be slightly advantageous in magnitude when compared to
other form of granite materials such as Harcrete (93% granite and Compressive strength
c=107.6 MPa) and Anocast
(with quartz having c of 110 to 117Mpa) [1].
Statistical analysis delineated that epoxy content had a significant influence of approximately 63% followed by
granite epoxy interaction influencing approximately close to 15% and granite grit ratio was less of approximately 2%
on the compressive behavior of composite. The pooled error associated was very less.
The observed results on experimentation compared the literature with regard to compression strength which leads its
application towards structural parts of machine tools.
REFERENCES
[1] Antonio P. F., Shimabukuro, F. “Characterization of Compression Strength of Granite-epoxy Composites Using
Design of Experiments”, Journal of Materials Research, 11:(4), 2008, pp.399-404.
[2] Lee G. D., Suh D. J., Kim S. H., Kim M. J. “Design and manufacturing of Composite high speed machine tool
structures”, Journal of Composite Science and Technology, 64, 2003, pp.1523-1530.
[3] Sulaiman, S., Yunus, R., Ibrahim, N. A., Rezaei, F. “Effect of Hardener on Mechanical Properties of Carbon
Fiber Reinforced Phenolic Resin Composites”. Journal of Engineering Science and Technology, 3:(1), 2008,
pp.79-86.
[4] Rama Krishna H. V., Padma Priya S., Rai S. K “Tensile, Impact, and Chemical Resistance Properties of
Granite Powder–Epoxy Composites”, Journal of Reinforced Plastics and Composites, 24, 2005, pp. 451-460.
[5] Antonio P.F., Flaminio L. P.”Behavior of Granite-Epoxy Composite Beams Subjected to Mechanical
Vibrations”. Journal of Materials Research, 13 :(4), 2010, pp.497-503.
[6] Selvakumar, A., Mohanram, P.V. “Analysis of Alternative Composite Material for High Speed Precision
Machine Tool Structures”. International Journal of Engineering. 2012
[7] Shetty R. R., Rai S. K. “Tensile, Flexural, Density and Void Content Studies on Granite Powder Filled Hydroxyl
Terminated Polyurethane Toughened Epoxy Composite”. Journal of Reinforced plastics and composites. 2008.
[8] Suh, D. J., Chang H. S., Lee G. D., Choi K. J., Park S. B., “Damping characteristics of Composite Hybrid
Spindle covers for high speed machine tools”. Journal of Processing Materials Technology, 113, 2001,
pp.178-183.