Which of the following statements is/are correct ?
1
Bituminous materials are used in highway construction because of their load bearing capacity.
2
Bitumen is derived from fractional distillation of petroleum.
3
The minimum value of group index for soil can be taken as zero, and the maximum possible value of group index for soil is twenty.
4
The group index of a soil subgrade is 6, the subgrade soil is rated as poor.