Solid-particle erosion of a geopolymer containing fly ash and blast-furnace slag

Solid-particle erosion studies were conducted on a geopolymer derived from fly ash and granulated blast-furnace slag. The erodent particles, 390 mum angular Al2O3, impacted at 30, 60, or 90degrees at a velocity of 50, 70, or 100 m/s. Steady-state erosion rates (ER) were obtained and the material-loss mechanisms were studied by scanning electron microscopy (SEM). The geopolymer responded to normal impact as a classically brittle material. Elastic-plastic indentation events led to formation of brittle lateral cracks that resulted in loss of materials erosion rate was proportional to erodent velocity to the 2.3 power. Impact at 60degrees produced similar results, with the erosion rates being in general slightly lower. Impact at 30degrees led to anomalously high erosion rates that were approximately independent of velocity. This response was attributed to presence of microcracks in the matrix and chipping of aggregates through propagation of radial cracks. (C) 2003 Elsevier B.V. All rights reserved.