Test Group | Clay Content (%) | pH Values | Number of Specimens |
1 | −10 | 4, 5, 6, 7, 8, 9, 10 | 28 |
2 | 0 | 4, 5, 6, 7, 8, 9, 10 | 28 |
3 | 10 | 4, 5, 6, 7, 8, 9, 10 | 28 |
4 | 20 | 4, 5, 6, 7, 8, 9, 10 | 28 |