Preparation of reconstituted sand samples in the laboratory

This paper compares the void ratio obtained in samples prepared by dry and moist tamping, and dry and wet pluviation. These 4 methods are amongst the few other commonly adopted methods used in the preparation of reconstituted sand samples in the laboratory e.g. slurry deposition and vibration. The samples were prepared in 100mm diameter and 200mm long split moulds. The effects of the number of soil layers and the drop height of the tamper, on particle packing, were studied in the tamping method. Microscopic images of these samples showed that the packing was more compact between the interface of two adjacent layers in tamped samples. In the pluviation method, the distance through which the sand particles were rained and the mass-flow were the two investigated parameters. The mass-flow was varied with the use of 3 different funnel openings. Frictional drag because of the air was ignored in the pluviation tests. The dry pluviation results seem to suggest that up to the limiting mass-flow, the funnel opening has a greater influence on the void ratio than the height through which the sand is rained. Furthermore, the tendency of the medium to dense air pluviated samples to dilate in drained triaxial test was not evident in the wet pluviated samples. The dilation was otherwise observed to be the maximum in dry tamped samples.