Concrete is a porous material and the ingress of water, oxygen, and aggressive ions, such as chlorides, can cause the passive layer on reinforced steel to break down. Additives, such as fly ash, microsilica, rice husk ash, and cane sugar bagasse ash, have a size breakdown that allows the reduction of concrete pore size and, consequently, may reduce the corrosion process. The objective of this work is to determine the corrosion rate of steel in reinforced concrete by the addition of 20% sugar cane bagasse ash by weight of cement. Six prismatic specimens (7 × 7 × 10 cm) with an embedded steel rod were prepared. Three contained 20% sugar cane bagasse ash by weight of cement and the other three did not. All specimens were placed in a 3.5% NaCl solution and the corrosion rate was determined using polarization resistance. The results showed that reinforced concrete containing sugar cane bagasse ash has the lowest corrosion rates in comparison to reinforced concrete without the additive.

A new predictive 3D FEM model is proposed using the corrosion damage function by measuring the concrete cover crack width, which is a function of the free concrete cover depth, the steel rebar diameter, the mechanical properties of the concrete, and the length of the anodic zone. A significant aspect to evaluate service lifetime conditions in corroded reinforced concrete structures (RCSs) is the concrete cover crack width. Surface cracks originate due to the pressure exerted by the volume expansion of the corrosion products and oxide layer formed on the rebars. In this work, concrete cover crack width on corroded RCS is analyzed by means of finite element method allowing a corrosion damage model to be proposed. The model obtained was used to find a theoretical relationship between the dissolved steel (corrosion process) and the concrete cover crack width. The results were validated using three experimental data sets from the literature: two corrosion case studies in natural environments and one work covering accelerated corrosion in laboratory test conditions. All the beams were exposed to the simultaneous action of flexural stresses and corrosion. A good correlation was observed between the model and the experimental results, thus supporting reliability of the analytical process and validation of the proposed corrosion damage model.

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In this paper is presented the application of the Method of Fundamental Solution (MFS) to obtain the solution of Laplace equation with linear boundary conditions to describe the distribution of potentials in corrosion cells. The results obtained by this method are compared with another numerical method, in this case finite element. As case of study takes the interior problem analyzed by McCafferty (1). In which two concentric electrodes placed in bottom of a cylindrical container, creating a galvanic cell. The results obtained by the MFS present a good agreement with the calculated by finite element.