CHAPTER 4: PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA 2009-2010
CHAPTER 4
PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA
In this various tests conducted on the specimens will be looked into. This study aims to
investigate the workability and the compressive strength of the concrete mixture which contains
natural fibers as an admixture. All the specimens were cured in a water tank before testing.
Natural fibers were added with the fiber-cement ratio of 0.10%, 0.15%, 0.25%, and 0.75%
respectively.
Table 4.1: Results of quality test for fine and coarse aggregates
TEST
COARSE
AGGREGATES
FINE
AGGREGATES
SPECIFIC GRAVITY 2622 2344
MOISTURE CONTENT 0.37 %
1.46 %
ABSORPTION 0.79 2.5
UNIT WEIGHT ------------------------- -------------------------
•LOOSE 1475 1412
•RODDED 1663 1610
FINENESS MODULUS - 2.82
Table 4.1 shows the result taken from the physical and mechanical test for fine and
coarse aggregates.
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CHAPTER 4: PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA 2009-2010
DESIGN PARAMETERS
These parameters were computed as stated in the ACI mix design method, the parameters
are the following:
Choice of slump…..………..25mm (minimum)
100mm (maximum)
Maximum aggregate size…..19mm
Mixing water……………….205 kg/m3 (non air entrained)
Water cement ration………..0.68 (non air entrained)
Cement content…………….301.5 KG
Coarse aggregate content…..1028kg
Fine aggregate content……..732kg
Mixing water…………........193.1 kg (adjustment for aggregate moisture)
Table 4.2: Summary of design mix
Quantities/(m3) Cement (kg) Water (kg) F.A (kg) C.A. (kg)Fiber
content
per m3 301 192 823 1032 -
Control 6.5 4.1 17.7 22 -
*0.10% 6.5 4.1 17.7 22 6.5
0.15% 6.5 4.1 17.7 22 9.75
*0.25% 6 3.8 16 20.5 15
0.75% 6 3.8 16 20.5 44.9
Table 4.2 shows the summary of the design mix as computed based on the ACI mix
design method.
* The 0.25% and 0.75% are the first trial mix; the factor of safety is 25%
* The 0.10% and 0.15% are the second trial mix; the factor of safety was adjusted to 35%
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CHAPTER 4: PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA 2009-2010
SLUMP TEST
The slump height was measured in terms of millimeters unit. The results of the test are as
follows:
Table 4.3: Results of Slump Test for first trial
SPECIMENS
*WEIGHT
OF FIBER
(g)
WEIGHT
OF
CEMENT
(kg)
WEIGHT
OF
SAND
(kg)
WEIGHT
OF
GRAVEL
(kg)
SLUMP
HEIGHT
(mm)
REMARKS
PASSED/FAILED
Control 0 6 16 20.5 50 passed
0.25% fiber content
Coconut coir 15 6 16 20.5 60 passed
Pineapple 15 6 16 20.5 18 failed
Sugarcane 15 6 16 20.5 20 failed
Abaca 15 6 16 20.5 21 failed
0.75% fiber content
Coconut coir 44.9 6 16 20.5 36 passed
Pineapple 44.9 6 16 20.5 20 failed
Sugarcane 44.9 6 16 20.5 6 failed
Abaca 44.9 6 16 20.5 19 failed
The design slump height for this research is from the range of 25mm to 100 mm, table
4.3 shows that only the normal concrete and the concrete which contains coconut coir has the
passing slump height.
*the weight of the fiber is based from the fiber-cement ratio stated in the previous chapter
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CHAPTER 4: PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA 2009-2010
Figure 4.1: slump test result for first trial
Figure 4.1 shows the result of the slump test done in the first trial of mixing. The design
range is from 25mm to 100mm, but the result shows that for nine batch mixes, majority of the
results are below the minimum slump height of 25mm. Compared to the control (normal
concrete), its slump height is 50mm which is within the design range. It only means that the
control has higher workability and consistency compared to the concrete mixture which contains
0.25% and 0.75% fiber content (pineapple, sugarcane bagasse and abaca)
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CHAPTER 4: PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA 2009-2010
Table 4.4: Results of Slump Test for second trial mix
SPECIMEN
*WEIGHT
OF FIBER
(g)
WEIGHT
OF
CEMENT
(kg)
WEIGHT
OF SAND
(kg)
WEIGHT
OF
GRAVEL
(kg)
SLUMP
HEIGHT
(mm)
REMARKS
PASSED/FAILED
Control 0 6.5 17.7 22 98 passed
0.10% fiber content
Coconut coir 6.5 6.5 17.7 22 83 passed
Pineapple 6.5 6.5 17.7 22 47 passed
Sugarcane 6.5 6.5 17.7 22 65 passed
Abaca 6.5 6.5 17.7 22 56 passed
0.15% fiber content
Coconut coir 9.75 8.2 16 22 62 passed
Pineapple 9.75 8.2 16 22 38 passed
Sugarcane 9.75 8.2 16 22 29 passed
Abaca 9.75 8.2 16 22 34 passed
Table 4.4 shows the result of the slump test for the second trial. The fiber-cement ratio in
this trial is 0.10% and 0.15% respectively. It shows that all the slump height is within the design
range of 25mm to 100mm
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CHAPTER 4: PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA 2009-2010
*the weight of the fiber is based from the fiber-cement ratio stated in the previous chapter
Figure 4.2: slump test result for second trial
Figure 4.2 shows the result of the slump test done in the second trial of mixing. The result
shows good results since all the slump height are within the design range of 25mm to 100mm,
but the concrete mixture which contains natural fibers (coconut coir, pineapple, sugarcane
bagasse, and abaca) are still lower than the plain concrete.
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CHAPTER 4: PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA 2009-2010
The figures below show the actual photos taken during the slump test made for
each batch mixes:
(a) (b)
Fresh concrete mixture which contains (a) 0.10% and (b) 0.15% sugarcane bagasse fiber
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CHAPTER 4: PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA 2009-2010
(c) (d)
Fresh concrete mixture which contains (c) 0.25% sugarcane bagasse and (d) 0.10% pineapple
fiber
(e) (f)
Fresh concrete mixture which contains (e) 0.15% pineapple fiber and (f) 0.25% pineapple fiber
(g) (h)
Fresh concrete mixture which contains (g) 0.10% coconut fiber and (h) 0.15% coconut fiber
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CHAPTER 4: PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA 2009-2010
(i) (j)
Fresh concrete mixture which contains (i) 0.25% coconut fiber and (j) 0.75% coconut fiber
(k) (l)
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CHAPTER 4: PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA 2009-2010
Fresh concrete mixture which contains (k) 0.10% abaca fiber and (l) 0.15% abaca fiber
(m) (n)
Fresh concrete mixture which contains (m) 0.25% abaca fiber and (n) 0.75% abaca fiber
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CHAPTER 4: PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA 2009-2010
COMPRESSIVE STRENGTH
As described in chapter 3, 27 concrete cylinders with the size of 150mm in diameter and
300mm in length were tested for compressive test. The specimens were tested at 6 days after
curing in a water tank. Specimens were tested for compressive strength by applying increasing
compressive load until failure occurs.
Table 4.5: Results of compressive test for first trial
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CHAPTER 4: PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA 2009-2010
The design compressive load for this mix design is 20.7 Mpa. Table 4.5 shows that the
entire specimen with natural fibers has lower compressive strength compared to the normal
concrete
* the remarks indicates whether the concrete cylinders failed or passed the desired compressive strength of 20.7Mpa
Figure 4.3: average compressive strength for first trial
Above figure shows the average compressive strength for each specimen for the first trial
where 0.25% and 0.75% fiber-cement ratio was used. In this figure, it can be seen that the result
was not good since at 0.75% fiber-cement ratio, the entire specimen produces low compressive
strength wherein it does not attain the desired compressive strength of 20.7 Mpa
Since the result of the first trial was not good, the researchers conducted another trial to
attain the design compressive strength wherein the fiber-cement ratio this time was limited to
0.10% and 0.15%
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CHAPTER 4: PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA 2009-2010
Table 4.6: Results of compressive test for second trial
Table 4.6 shows the result of the compressive strength test for the second trial. Among 27
specimens, only 2 specimens does not attain the design compressive strength of 20.7 Mpa
* the remarks indicates whether the concrete cylinders failed or passed the desired compressive strength of 20.7Mpa
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CHAPTER 4: PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA 2009-2010
Figure 4.4: average compressive strength for second trial
Above figure shows the difference in compressive strength of all the specimens in every
type of fiber and fiber-cement ratio of 0.10% and 0.15% respectively. It clearly shows that at
0.15% fiber content, all the specimens increases their compressive strength by 3% up to 26%
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CHAPTER 4: PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA 2009-2010
Figure 4.5: average compressive load vs. fiber percentage
Figure 4.5 shows the average compressive strength of the concrete mixture containing
coir fibers, sugarcane bagasse, pineapple fibers and abaca fibers is greater at the 0.15% fiber-
cement ratio and decreases at 0.25% and 0.75% fiber-cement ratio. The figure shows that
sugarcane bagasse at 0.15% fiber-cement ratio has the highest compressive strength of
26.423Mpa which is 26% higher than the normal concrete.
EFFECT OF PERCENT FIBER
The main effect of the percent fiber contribution can be seen also from the figure 4.5. The
figure shows the average compressive strength for each specimen. The plot indicates that as the
fiber content increases from 0.10% and 0.15%, the compressive strength also increases, but
decreases as the fiber content increases from 0.25% and 0.75%.
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CHAPTER 4: PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA 2009-2010
The figure below shows the photos taken after the compression test was done. Cracks can
be seen and the facture can be classified by investigating the crack formation.
(a) (b)
Figure 4.6 (a) concrete mixture which contains 0.25% abaca and (b) concrete mixture which
contains 0.75% abaca after compression test was done
(a) (b)
Figure 4.7: (a) concrete mixture which contains 0.25% pineapple and (b) concrete mixture
which contains 0.75% pineapple after compression test was done
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CHAPTER 4: PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA 2009-2010
(a) (b)
Figure 4.8: (a) concrete mixture which contains 0.25% sugarcane and (b) concrete mixture
which contains 0.75% sugarcane after compression test was done
(a) (b)
Figure 4.9: (a) concrete mixture which contains 0.25coconut coir and (b) concrete mixture
which contains 0.75% coconut coir after compression test was done
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CHAPTER 4: PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA 2009-2010
Figure 4.10: concrete mixture that contains no fiber after the compression test.
By investigation, all the concrete cylinders which contain natural fibers, from 0.25% and
0.75% fiber content, the cracks made by the ultimate load is quite minimal compared to the
concrete cylinder which contains no fiber. In figure 4.10, it can be seen that the control splits into
two after the test was done, unlike the other specimens; they only produce short cracks in some
area of the cylinder. The probable reason is that, fibers which are randomly placed as the fresh
concrete is mixing, the fibers hold the particles, which act as the roots of the mixture, which can
help lessen the formation of cracks even if it attained its ultimate load.
.
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