Permeability of Panki fly ash under stress

Abstract

The influence of stress state on permeability of fly ash has been investigated using a combined setup of odometer and falling head permeability devices. The specimens have been prepared using air pluviation method for obtaining loosest state, standard proctor test for compacted state, and soaking method under load for weathered state of Panki fly ash. A series of 1-D consolidation tests at different loading conditions have been performed on these specimens, and then the permeability of fly ash has been obtained for constant stresses of 27 kPa, 71 kPa, 143 kPa, 269 kPa, 528 kPa and 1046 kPa for three types of specimens. The correlations have been developed between permeability and stress values for all three cases considering the effect of initial state of the specimen. This research can be useful for designing and construction of civil engineering structures such as ash dyke, highway and railway embankments, small dams and other structures where continuous external forces act on them. Permeability of Panki fly ash was obtained to be significantly lower for soaked state as compared to loosest and compacted state of fly ash under given stress level possibly due to the formation of some substances between the particles during soaking of fly ash under water for 18 days indicating weathering reaction.