Void distributions in samples of Ottawa sand

Abstract

The void distribution of saturated specimens of Ottawa sand is presented. The presence of water inside the sand specimen is detected using the magnetic resonance imaging (MRI) technique. The void distribution of the sample was determined from the image. The specimen was prepared in a non-metallic triaxial cell and was put insie a MRI apparatus to obtain the image. Two sample preparation methods (wet tamping and dry pluviation) were used to illustrate the uniformity of the samples in the initial state. The void distribution along the height of the sample and the three-dimensional orientational void distribution at different locations inside the sample were analysed. The results indicate that the sample generated by the drypluviation method is more uniform than the sample generated by the wet-tamping method. When the wet-tamping sample preparation technique is used, the dense sample is more uniform than the loose sample. The development of voids was investigated by a sample loaded inside the MRI device under drained compression condition. The void distribution along the height of the sample at different stages was observed. This work has demonstrated the feasibility of using the MRI technique to examine void distribution in granular material.

Aspects of simulating the dynamic compaction of a granular ceramic

“…First, this range of volume fraction is near the MPD of ρ 00 = πρ 0 /4 = 12.2 g cm −3 or 78.5% volume fraction. Second, this range of volume fraction encompasses the range of localized density variations known to exist in some dry granular materials; measurements of density gradients within dry poured Ottawa sand have been reported to be as high as 10% [56].…”