Cracking in Reinforced Concrete Structures Damaged by Artificial Corrosion: An Overview

Background:

Corrosion of the reinforcing steel is a significant issue in construction engineering. As the corrosive attack propagates, the oxides accumulated on the steel-concrete interface cause a radial internal pressure in the structural element and induce a tensile stress state in the concrete with the consequent cracking. Except for few cases, the main outcomes on the behavior of reinforced concrete structures damaged by corrosion come from experimental results on artificially corroded specimens. For many years, the scientific community has been discussing the feasibility of artificial techniques to simulate the corrosion process in structural element. Specifically, the most disputed method is the accelerated electrolytic corrosion test, often characterized by high current intensities in order to reduce the duration of the experimental surveys.

Objective:

In the paper the influence of the current density on the degradation of a reinforced concrete element is investigated with particular reference to the kind of formed oxides and to the crack width.

Methods:

An experimental survey on steel rebars embedded in concrete cylinders and subjected to an electrolytic corrosion has been performed, with different increasing current densities. Furthermore, an analytical model, based on the classical thick-walled cylinder theory already proposed by the authors, is applied for validating the experimental results.

Results:

The oxides produced by artificial corrosion with different current densities are analyzed with X-ray diffractometry measurements. The influence of the current density on the crack widths is also pointed out.

Conclusion:

The analyses of the obtained results show that for the analysed specimens and current density range, no significant differences are found for the oxides composition. On the contrary the influence of the current density on the crack width is pointed out, and an upper limit of this parameter is indicated.

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