Electrical Disintegration of Reinforced Concrete: Experiment and Simulation

Abstract

The paper reports on physical experiments on disintegration of reinforced concrete by the electric pulse method based on the Vorobiev effect. Concrete is fractured under the action of a compression wave propagating from the discharge channel between the electrode on the concrete surface and the reinforcement. Disintegration experiments are conducted on pebble concrete. It is shown that a single pulse results in separate cracks in the material on retention of its integrity. Disintegration of concrete and cavitation at the point of application of the electrode begin after the second or third pulse. Computer simulation is made for the action of an expanding discharge channel on reinforced concrete. A structural model of reinforced concrete is plotted, explicitly taking into account its main constituents, namely, cement, stone inclusions, and reinforcement. The inelastic behavior of cement is described within the modified Drucker–Prager–Nikolaevsky model with the nonassociated flow rule for quasi-brittle media. Cracking is simulated using the fracture criterion based on tensile stresses. The performed numerical simulation confirms the conclusions of the physical experiment: a single pulse causes the formation of separate cracks parallel to the free surface, and the network of horizontal, vertical and inclined cracks appears in the cement after 2–3 pulses, resulting in a cavity at the point of application of the electrode. Cavitation in reinforced concrete is governed by the presence of stone inclusions, whose boundaries serve as sites of redistribution of maximum tensile stresses and formation of vertical and inclined cracks, as well as of accumulation of irreversible strains and stresses retained in the cement after the first pulse.