Finite Element Modelling of Steel Corrosion in Reinforced Concrete Cylinders

Abstract

Corrosion of reinforcement steel is a major factor affecting the deterioration of reinforced concrete structures. During corrosion, steel undergoes several phases of chemical reactions with consequent variation in steel section geometry and mechanical properties. At ultimate corrosion stage, the effective cross section area of steel is reduced with equivalent decrease in load carrying capacity leading to unsafe structures. During initial phase of corrosion, chemical reactions generate new products which irregularly increase steel bar diameters. The resulted products induce additional stresses on the structural member, causing cracking and spalling of the concrete cover, and subsequently faster deteriorate the member strength. This paper presents the effect of the induced stresses of corrosion products on concrete cracking experimentally and numerically. Experimentally several pull-out specimens were tested to identify the effect of corrosion at different stages, and, numerically, a two dimensional finite element model was developed to study the crack initiation and propagation in concrete using nonlinear analysis and specific properties for both steel and concrete elements.