No abstract

This work studies the influence of the saline atmospheric corrosion on the fatigue strength of 6061-T6 aluminum alloy. For this purpose, this alloy was subjected to tests in a salt spray corrosion chamber at different exposure times (1, 2, and 3 months) according to ASTM B117 standard. The morphological study of the pits was carried out by confocal microscopy. Subsequently, fatigue tests were performed at variable stresses whose maximum stress (Smax) was between 30% and 95% of the yield strength (S0) in order to keep them within the zone of elastic behavior of the material. Data were analyzed using the Basquin equation and the maximum likelihood function method. The results show a similar decrease in the conventional fatigue limit (2 × 106 cycles) after one month (98 MPa) and two months (91 MPa) of corrosion. After three months of corrosion, the material showed a very important reduction in the fatigue limit (68 MPa) with respect to the uncorroded material (131 MPa). The data of Se/S0 (fatigue limit/yield strength) versus the ratio Pm/Dm (pit average depth/pit diameter at zero depth) can be fitted to a logarithmic curve.

This article describes the elasto-plastic model that has been applied to analyse the beams damaged by corrosion. CONTECVET Manual, which contains the principles of this kind of structural evaluation, has been adopted. This Manual recommends considering the reduced section of the concrete and of the reinforcements as well as the possible reduction of the concrete steel bond. The first part of the article describes the basis of the structural model and, the mechanical behaviour of the materials. In the second part, the results of the experimental tests are presented and compared with the results of the model. The results indicate an enough good accordance, if the typical scatter of this type of experimental tests is taken into account.RÉSUMÉ. Cet article décrit le modèle élastoplastique qui a été appliqué aux poutres endommagées par l'effet de la corrosion. Comme base de l'évaluation structurelle est pris le manuel CONTECVET où les principes de ce type d'évaluation ont été presentés. Le manuel montre le besoin de tenir compte des sections réduites du béton et de l'armature ainsi que de la possible réduction de l'adhérence béton/armature. La première partie de cet article expose les bases du modèle structurel considéré et le comportement mécanique des matériaux. Dans la deuxième partie, les résultats de laboratoire sont présentés et comparés avec le modèle. Les résultats indiquent que la résistance finale est prédite d'une manière suffisamment précise si on tient compte de la dispersion typique asociée à ce type d'essai.

No abstract