Some engineering properties of volcanic sand

Pumice sand is widespread over the central part of the North Island due to frequent past volcanic activity. The pumice has distinct properties different from that of quartz sands. The index and engineering properties are reviewed. The most significant difference from typical quartzitic sands is the grain softness of pumice. The particles are easily crushed by a finger nail. The other major difference is the void ratio, which is about twice that of typical quartz sans. This two factors are suggested as being substantially responsible for its different behaviour, as found ins a series of consolidated drained triaxial tests on specimens with free end platens.