Abstract
Pond ash, being a form of coal ash, consists mainly of glassy particles with a significant percentage containing internal occluded voids. By analysing the evolution of particle size distribution before and after triaxial testing at normal stress range using a Laser Particle Size Analyser, specific gravity and SEM photography, it was found that these hollow particles may breakup as a result of shearing. This type of particle disintegration is different from localised grain crushing or shearing off of asperities at high contact stress points. The stress-strain responses measured in an extensive programme of triaxial testing were synthesised. It was established that a unique and consistent critical state line was achieved, irrespective of initial state, drainage conditions and stress histories. Furthermore, the overall pattern of stress-strain responses was related to the location of initial state relative to the critical state line. This supports the use of critical state soil mechanics framework in synthesising and modelling the stress-strain behaviour of pond ash.
