Cavitation damage to geomaterials in a flowing system

Short-time cavitation erosion of rocks and cementitious composites is investigated in a laboratory flow cavitation chamber. Cavitation erosion with an exposure time as low as 10 seconds generates measurable damage. Mineral composition plays a major role in the cavitation erosion of the material. The erosion mainly occurs in an intergranular or intercrystalline mode, respectively. Fracture toughness of rock and conventional concrete is a good indication of cavitation erosion resistance. However, density is a second important evaluation parameter; materials with a low degree of pre-existing flaws, namely glass and high-strength silica cement, show an extraordinary high erosion resistance. The cavitation erosion of the rock materials tested in this study is always higher than that of conventional concrete mixtures. Elastic strain energy density is not a measure of cavitation erosion resistance of rocks and cementitious composites. A parameter Phi = d(M) . E-M . rho(M)/K-lc(n) to approximate the cavitation erosion resistance of the materials. The parameter n is a function of the R-curve-behavior. (C) 2003 Kluwer Academic Publishers.