A: Only for collapse testing (Method C). Swell testing is irrelevant for non-cohesive, granular soils because they lack clay minerals.
A: Typically 3 to 7 days, depending on soil permeability. High-plasticity clays (CH) may require up to 14 days for full swell to stabilize. Astm D4546-21 Pdf
The standard that governs how to test these phenomena in a laboratory is . If you are currently searching for the "ASTM D4546-21 PDF," you likely need the official document for a quality control plan, a university research project, or a specific construction specification. A: Only for collapse testing (Method C)