Cavitation erosion of concrete

Conclusions

• 1. The choice of components and composition of concrete should be based on consideration of all factors of both the environment and the concrete that can have an effect on its cavitation resistance, including the climatic factor and degree of corrosiveness and erosiveness of the water.

• 2. Concrete should be of high strength and uniformity and the concrete mix should be plastic for the placement method used. Evidently we can consider correct the suggestions of the “Methodological Recommendations” that the concrete grade should be 400 at 28 days. Higher grades can be recommended only if this does not involve a considerable increase in the cement content.

• 3. The frost resistance of concrete, especially in the surface layer, should be high. To increase it, it is recommended to use the additive hydropolysiloxane GKZh-94 at a rate of 0.2% of the weight of cement, which has shown good results. The use of other additives after conducting appropriate investigations is also possible.

• 4. To establish more confidence and to check the quality of concrete undergoing cavitation, it is necessary to develop a new criterion of frost resistance of the surface layers exposed to cavitation and to provide an appropriate method for determining it.

• 5. Both gravel and stone not containing weathered rocks, clean, and of good granular composition (with respect to the State Standard) can be used equally well as the coarse aggregate in cavitation-resistant concrete.

• 6. The surface of the concrete should be compact, smooth, and well streamlined to the flowing jet.