Question

Bitumen grade 80/100 indicates that under the standard test conditions, the penetration value of bitumen would vary from:

• A. 0.08 mm to 0.1 mm
• B. 80 mm to 100 mm
• C. 0.8 mm to 1 mm
• D. 8 mm to 10 mm

Hint:

In penetration grading, the number represents tenths of a millimeter of penetration at 25°C under 100 g load for 5 seconds.

Answer 1

The Correct Option is B

Step 1: Understanding penetration grade of bitumen.
Penetration test measures the hardness or softness of bitumen by measuring the depth (in tenths of a millimeter) to which a standard needle penetrates under standard test conditions.

Step 2: Apply given grade.
Bitumen grade 80/100 means that the penetration value lies between 80 and 100 tenths of a millimeter, i.e., between 8.0 mm and 10.0 mm.

Step 3: Match with given options.
Option (B) is correct: 80 mm to 100 mm (in tenths of a mm, i.e., penetration units).

Step 4: Conclusion.
Therefore, the penetration value of 80/100 grade bitumen is 80 to 100 (0.1 mm units), i.e., option (B).