Volume 24, Issue 4 (December 2001)
Determination of Specific Gravity and Void Ratio of Pumice Materials
The vesicular nature and the soft grains of pumice deposits create difficulties in testing them and in interpreting the test results. This note examines the difficulty of measuring specific gravity and estimating void ratio. The difficulty arises from the presence in the particles of a network of internal voids or vesicles, some of which are interconnected and open to the external surface, while others are isolated inside the particle. The void ratio measured by conventional methods invariably includes some of the internal void space, and is therefore, not a true measure of void ratio in terms of the normal definition or understanding of the term. This paper examines different ways of measuring the specific gravity, and the influence of particle size on the results.