THE FRACTURE OF CONCRETE DUE TO EROSIVE WEAR BY HIGH-VELOCITY WATER-FLOW

Wear and erosion of concrete structures by high velocity water flow is a basic aspect of the durability of marine and water constructions. T he mechanism of concrete failure in such constructions is not well und erstood. Using high velocity water jets for simulating the loading, th e authors observed the general behavior of the material during failure and investigated the influence of water velocity and exposure time. T he results show that the interface between hardened cement paste and a ggregate grains plays the main rob in the fracture process. The basic mechanism of material failure is the generation and propagation of cra cks at this interface. It is found that a critical loading intensity, which is characterized by a threshold velocity and a threshold exposur e time, must be achieved in order to induce the erosion process. Throu gh mass removal measurements, a mathematical relation between both par ameters and the erosion intensity is found. Using a computer program f or simulating the hydrodynamics inside a crack, the water pressure and flow velocities in a modal crack were calculated.