Development of New Robust Procedures for the Determination of Maximum and Minimum Dry Densities of Sand-Paper

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The study developed and validated new procedures for measuring the maximum and minimum dry densities (ρmax and ρmin) of sand. Existing methods can produce substantially different results, affecting calculated relative density and making laboratory results difficult to compare.<br /><br />The maximum-density procedure adapts a Geolabs method: saturated sand is compacted in a mould using vibration and a surcharge. The final procedure uses one layer, a clamped mould, controlled vibration and limited water. Tests across six laboratories found good agreement, particularly for the revised Phase 2 procedure. Particle-size analyses showed no evidence of grain crushing. Results on sands from an earlier study were generally higher than those obtained with existing standard methods.<br /><br />The minimum-density procedure uses a funnel to place loose sand into a mould as the funnel is steadily raised. Careful control of the sand quantity, lifting speed and levelling is essential. Results were generally repeatable within laboratories, though differences between laboratories were larger, especially for sands with higher fines content. The procedure is recommended for sands with less than 12% fines. On previously tested sands, its results were generally lower than those from existing methods.<br /><br />Testing covered four sands with varying grain sizes and fines contents, followed by validation on six additional sands. The authors conclude that the procedures have strong potential to provide consistent, transferable measurements and recommend them as a basis for future specifications and international standards.

Keywords

sand density

maximum dry density

minimum dry density

relative density

laboratory validation

vibration compaction

funnel method

grain size

fines content

international standards