Expansive clays, collapsing sands, unbound pavement materials and unsaturated soil theory

Fredlund (2002) demonstrated by an example (Regina clay, solute suction 150 to 200 kPa) that solute suction is relatively more important than matric suction when suctions are low; the opposite applies at higher suctions such that total suction may be almost the same as matric suction at levels of suction greater than 1,500 kPa (Fredlund 2002). For more saline soils, a correction may be appropriate.