Dynamic Properties of Fly Ash

Due to the ever-increasing demand for electricity, generation of fly ash in large quantities has become a problem throughout the world. The utilization of fly ash in rail and road embankments in earthquake-prone areas requires thorough understanding of its dynamic strength characteristics. A series of resonant column and cyclic triaxial tests have been carried out on fly ash to investigate the influence of various factors on its maximum dynamic shear modulus (Gmax) and dynamic damping (Ds). Correlations for predicting Gmax and Ds for fly ash have been proposed. The fly ash is found to be far more liquefiable than sand. The particle-size distribution and low unit weight play a vital role in the determination of cyclic strengths. The dynamic shear damping is found to be very much influenced by the confining pressure and induced strain, but independent of the relative density of the fly ash. The damping of sand is found to be always more than the damping of the fly ash irrespective of the confining pressure.