Issue 50

M. Ameri et alii, Frattura ed Integrità Strutturale, 50 (2019) 149-162; DOI: 10.3221/IGF-ESIS.50.14

glass fiber (for determining the optimum bitumen percentage) were 0.3 % of the weight of the asphalt mixture. Tab.3 shows control parameters of optimum bitumen percentage for 3 group samples.

Figure 2 : The shape of fiber (a) basalt fiber b) glass fiber [14].

Glass fiber

Basalt fiber

Element

Oxide

Oxide mass percentage

Element mass percentage

Oxide mass percentage

Element mass percentage

Al Si Ca Fe

Al

O 2

11.86 58.25 21.09

6.3

17.35 42.43 8.88 11.68 2.33 9.45 3.67

9.17 19.76 6.37 8.17 1.94

3

2 SiO CaO

24.24 15.05 0.21 0.36 0.32 0.22

Fe

O 2 O 2

0.3

3

K

K

0.43 0.54

Mg Na

MgO

5.7

Na

O 2

0.3

2.81 1.53

0.41

0.25

2.55

Ti

TiO

2

Table 2 : Component for basalt and glass fiber material [14].

Control Samples

Parameters

Glass

Basalt

Marshal stability at optimum percentage

883

807

854 3.15 74.3 15.2

Flow at optimum percentage

4.2

3.6

Percentage of empty space filled with bitumen

74.7 15.6

75

Percentage of empty stone materials per percentage of possible bitumen

15.7

Table 3 : Parameters for controlling optimum bitumen percentage.

E XPERIMENTAL TEST

Indirect tensile strength test ndirect tensile strength test is often used for evaluation of moisture sensitivity of asphalt mixtures. The produced asphalt samples are divided into two groups, dry and wet. In order to produce dry samples, before breaking them, their temperature should reach to the room temperature. For this purpose, the samples can be put in plastic bags to prevent it from getting wet and then they should be saturated at least for 1 hour in water at 25°C temperature. For producing wet sample in vacuum, the wet samples should be put in vacuum instrument. Saturate ratio should be between 55 - 80 percent of the asphalt vacant place. If the samples saturation is more than 80%, that sample should be removed. Then, the samples are put vertically between the two jaws of the indirect tensile strength instrument. Diagonal load is I

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