Numerical Modeling of Cathodic Protection for Sustainable Cementitious Materials Incorporating Rice Husk Ash

Abstract

Reinforced concrete (RC) structures are widely used in engineering due to their physical, chemical and mechanical characteristics that guarantee good durability. However, one of the main mechanisms of degradation of these structures is associated with the corrosion of the reinforcement, which often occurs due to carbonation of the concrete and/or the presence of chloride ions. To avoid or mitigate the corrosive process of the reinforcements, one of the most used techniques is the cathodic protection (CP). To design new CP systems or verify existing ones, numerical computational simulations based on the boundary element method (BEM) are used. This work aims to analyze CP systems in RC beams using BEM and experimental input data: resistivity and cathodic polarization curves. The latter are obtained experimentally and represent the relation between the applied current and the electrochemical potential generated on the metal surface. For that, three different environmental conditions were taken into account: after curing (100 days), immersed in distilled water and immersed in seawater. The cementitious materials used were pastes and concretes, without addition of rice husk ash (RHA, reference samples), and with addition of 20% of RHA. The resistivity values decreased after curing in distilled water and in seawater, as expected. The simulations show that the efficiency of the cathodic protection system depends on the impressed current intensity and the geometric arrangement of the anodes.