L’influence de la corrosion sur le comportement mécanique d’un tablier d’un pont

Abstract

In recent decades, many buildings in Algeria were made of reinforced concrete. The structures, in general, and the bridges, in particular, are subject to several chemical and mechanical reactions that can alter and influence the mechanical behavior, and eventually, the bearing capacities of these structures over the years. One of the main causes of this deterioration is the corrosion of reinforcement. Like some diseases of the concrete itself, the steel corrosion in concrete is a physico-chemical process, an issue that does not, therefore, pertain to the engineers' mechanics-oriented culture in the construction industry. The damage due to corrosion is manifested by metal expansions leading to the formation of cracks that may cause the detachment of the concrete cover. In addition to the loss of the concrete cover, structural damage to the structure may occur, due to the loss of traction bars and the reduction of their original diameter (loss of tensile capacity). Corrosion develops mainly during two processes: on the one hand, the carbonation of concrete becomes slow and uniform along the frame and, on the other hand, the attack by chlorides which, being present in sufficient quantities at the edge of the frame, generate pitting. This process is rapid and highly localized in kinetic term. When the corrosion becomes active, the mechanical behaviour of the structure changes. This is chiefly due to the decrease in the section of corroded reinforcement. The volume of steel corrodes is significantly greater than that of sound steel. This increase in volume creates pressure on the concrete and the crack. The objective of the present research work is to study the influence of corrosion on the mechanical behavior of structures to approximate the behavior of corroded reinforced concrete. This undertaking requires the knowledge of many experimental parameters. The means of protection of steels are numerous but few of them can be effective in the case of frames because they have not only to protect the steel surface but also meet a number of other conditions. In fact, the adhesion between reinforcement and coated concrete must meet the required values through standardization, and the coating must be stable in the pore solution of cement paste.