Buton Epure

Buton Epure

Buton Epure (BE) is a natural asphalt originally from Buton Island which contains filler from the same origin and having very good quality for asphaltic concrete mixture (grading IV, maximum size 19.1 mm).

BE-50 (consists of 50% asphalt and 50% filler) is produced by reducing the soil (filler) content in the Buton rock asphalt (Asbuton). The process is carried out by extraction, then the extracted bitumen is improved and added by selected filler which has been prepared, to make type of Buton Epure products. This Buton Epure is homogeneous binding material suitable for heavy road construction.

Up to now, there is still no specific standard for Buton Epure type (mixture of asphalt, filler and additive) in Indonesia or in other developed countries. However, by comparing the results of the Marshall test for asphaltic concrete mixture between Petroleum Asphalt and BE-50, it is proved that BE-50 has very superior characteristic especially in its stability. The stability is higher than 1,000 kg (specification standard > 800 kg). By using procedure in production of Buton Epure concrete mixture, all conditions in the Marshall test specification standard for asphaltic concrete mixture (grading IV) was fulfilled.

Buton Epure can be used for heavy road and high performance construction. For road having lower sub grade, this type of asphalt mixture will bring no problems. In developed countries which have implemented Superior Performing Asphalt Pavement (Superpave) construction, this type of asphalt mixture will meet the expectation as it will fulfill the expected criteria.

In the development of asphaltic concrete, attention should be paid on the workability which is influenced by the viscosity of the binder material (Buton Epure). For this purpose, BE-50 is used for preparing an asphaltic concrete mixture. However, in the field due to asphalt absorption and based on the mix design, BE-55 is used. The viscosity of Buton Epure is in the range of 996.5 to 418 cst at temperature between 150 and 163ºC for BE-50. For BE-55 the viscosity is at 389.7 to 197.1 cst at temperature between 145 to 160ºC.

Table 1. Quality of BE-50

No.

Type of Testing

Result

1.

Penetration, 0.1 mm

2

2.

Ductility, cm

3.5

3.

Flash Point, ºC

undetectable

4.

Softening Point, ºC

70.25

5.

Specific Gravity, g/cc

1.3908

6.

Loss on Heating, %

0.693

7.

Penetration after Loss on Heating, % original

0

8.

Solubility in CCL₄, %

91.011

Table 2. Quality of Asphaltic Concrete BE-50 content of – 11% and external filler 0.3%

No.

Standard Specification Values

SP BM***

SP AI

BE-50, 11% and

external filler 0.3%

1.

Stability

> 800 kg

–

4,088 kg

2.

Flow

> 2 mm

–

2.25 mm

3.

Voids in the mineral of aggregate (VMA)*

> 16%

> 13%

15.37%

4.

Voids in the Mix

(VITM)

3 - 5%

–

4%

5.

Voids filled with asphalt (VFWA)

> 75%

65 - 75%**

73.87%

6.

Marshall Quotient

200 - 500 kg/mm

–

1816.89 kg/mm

Legend:

*

for aggregate of maximum size 19.1 mm

**

for load > 100 million ESALs

***

SP = Superpave

BM = Bina Marga or Indonesia Road Construction Standard

AI = Asphalt Institute

END
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