71 Based on the Figure 4.34, it can be seen that the added of crumb rubber into 5 had the
highest score of VMA and the score was almost same with 0 Crumb Rubber. Then, the other crumb rubber added showed almost similar score of VMA.
4.2.7 Indirect Tensile Strength Test ITS
The next test was conducted for Indirect Tensile Test ITS. This test was used 0, 3, 4 and 5 of crumb rubber with 30
o
C, 40
o
C, and 60
o
C. The result of ITS test for 0 of crumb
rubber is presented in Table 4.14. In terms of ITS, the formula is already mentioned in formula 2.2. The calculation of ITS for
ITS30
o
C is as follow:
Sample A= 80
. 74
101 14
. 3
1000 2461
. 25
1000 2
= 2128.490294
Sample B = 05
. 73
101 14
. 3
1000 11525
. 63
1000 2
= 5448.702052
Sample C = = 3859.662399
Average = = 2994.08 MPa
ITS for 40
o
C are as follow:
Sample A= 10
. 76
101 14
. 3
1000 50835
. 19
1000 2
= 1616.645716
Sample B = 50
. 76
101 14
. 3
1000 41002
. 23
1000 2
1929.8312
Sample C = = 1593.248775
Average = = 1604.95 Mpa
ITS for 60
o
C are as follow:
Sample A= 25
. 71
101 14
. 3
1000 67216
. 3
1000 2
= 325.0242021 perpustakaan.uns.ac.id
commit to user
72 Sample B =
74 101
14 .
3 1000
06559 .
2 1000
2 = 176.0319
Sample C = = 585.5860013
Average = = 455.305 Mpa
TABLE 4.14.ITS AC type
OBC ITS 30 C MPa
ITS 40C MPa ITS 60C MPa
without CR 5.60
2994,08 1604,95
455,305
with CR 3 5.485
2300 1088,6
418,281
with CR 4 5.55
2469.45 696.72
207.16
with CR 5 5.425
1404 913,4
238,1 Through review of the results of ITS test in Table 4.14 and Figure 4.35 were obtained the
observations following
Figure 4.35. ITS Test
From the figure 4.35 it is obvious that asphalt concrete without crumb rubber demonstrated the far less temperature sensitivity in comparison with asphalt concrete with
crumb rubber. As the ITS value of asphalt concrete without crumb rubber is higher than asphalt concrete with crumb rubber at different temperature. However, among three different
percentage of crumb rubber, asphalt concrete with 3 CR showed the most satisfactory result
500 1000
1500 2000
2500 3000
3500
30oC 40oC
60oC
ITS M
P a
Temperature
CR CR 3
CR 4 CR 5
commit to user
73 since the ITS value of 3 CR was more close to the ITS value of 0CR even after softening
temperature at 40
o
C compared with two others. Besides, the ITS value of two others percentage of crumb rubber was reduced drastically with the increasing of temperature.
4.2.8 Unconfined Compressive Strength UCS Test
