ASTM D4546-21 outlines three laboratory procedures (Methods A, B, and C) for determining one-dimensional swell or collapse of soils, focusing on measuring swell pressure and free swell. This 10-page standard applies to unsaturated soils to evaluate volume changes under vertical stress. The official document is available for purchase at the ASTM International Store . ASTM D4546-21: Soil Swell Testing Methods | PDF - Scribd
Lab tests utilize full inundation, creating an extreme saturation state ( Astm D4546-21 Pdf
Simulates the conditions of compacted fills. Multiple identical specimens are loaded under various stresses and then wetted to determine free swell, swell pressure, and load-dependent swell/collapse curves. Test Method B Intact (Natural/Undisturbed) Astm D4546-21 Pdf