Compression Index and Small Strain Stiffness of Six Coal Bottom Ashes in South Korea

This study investigates the small strain stiffness (G(max)) of six coal bottom ashes in South Korea. One-dimensional compression tests using an instrumented oedometer cell were performed to measure the shear wave velocity (V-s), and the compression indices (C-c) of the six different bottom ashes were also explored in this study. The results demonstrate that, at low confinement, theC(c)of bottom ashes are comparable to that of sand under a similar void ratio. However, at high confinement, the bottom ash shows very highC(c)compared to sand due to the crushability of the weak and porous bottom ash particles upon confinement. The variations of alpha and beta, which areV(s)parameters (i.e.,V-s=alpha(sigma '(m)/1 kPa)(beta)), with differentC(c)values of the tested bottom ashes are consistent with the existing empirical relationship. TheG(max)of tested bottom ashes can be adequately captured by the existingG(max)estimating formula for angular sand, indicating that theG(max)of bottom ash is highly comparable to that of sand with a similar void ratio and confining stress.