The penetration value of a bitumen sample tested at 25°C is 80. When this sample is heated to 60°C and tested again, the needle of the penetration test apparatus penetrates the bitumen sample by d mm. The value of d can’t be less than ___ mm.
A. 5
B. 8
C. 10
D. 20
Answer:B
The penetration value of a bitumen sample tested at 25°C is 80. When this sample is heated to 60°C and tested again, the needle of the penetration test apparatus penetrates the bitumen sample by d mm. The value of d can’t be less than ___ mm.
A. 5 B. 8 C. 10 D. 20