| General classification | Granular materials 35% or less passing 0.075 mm |
Silt / Clay materials more than 35% passing 0.075 mm |
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|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Group classification | A-1-a | A-1-b | A3 | A-2-4 | A-2-5 | A-2-6 | A-2-7 | A4 | A5 | A6 | A-7-5 | A-7-6 |
| Sieve analysis - % passing 2.000 mm 0.425 mm 0.075 mm |
<=50 <=30 <=15 |
<=50 <=25 |
<50 >=10 |
<=35 | <=35 | <=35 | <=35 | <=35 | <=35 | <=35 | <=35 | <=35 |
| Caractéristiques of fraction passing
0.425 mm Liquid Limit Plasticity index |
<=6 | <=6 | NP | <=40 <=10 |
>40 <=10 |
<=40 >10 |
>40 >10 |
<=40 <=10 |
>40 <=10 |
<=40 >10 |
>40 <=LL-30 |
>40 >LL-30 |
| Group index | 0 | 0 | 0 | 0 | 0 | <=4 | <=4 | <=8 | <=12 | <=16 | <=20 | <=20 |
| Usual types of significant constituent materials | Stone fragments gravel and sand | Fine sand |
Silty or clayey gravel and sand | Silty soils | Clayey soils | |||||||
| General rating as subgrade | Excellent to good | Fair to poor | ||||||||||
| ISS 2500 rating | Fair to poor* | Un- suit- able* |
Excellent to good | |||||||||