Influence of an aqueous environment on the fretting behaviour of steel wires used in civil engineering cables

Civil engineering cables are submitted to important loadings and are often exposed to severe environmental conditions (marine environment, rain, pollution, …). They are subjected to two main damage phenomena which are fretting-fatigue and corrosion. The influence of water on the fretting behaviour between two cable wires is investigated in this paper. Fretting tests on cold drawing steel wires were performed in this study for two different configurations (in air, and in water). For each configuration, the experimental results permit to identify the friction coefficients and the different sliding regimes (partial slip regime, mixed regime and gross slip regime). It is shown that, for small strokes, water does not change the contact conditions, and acts as a lubricant for higher strokes. The friction coefficients in gross slip regime and at the transition are strongly reduced in water compared to air. Damage mechanisms, in particular cracking, are observed for both environments. They depend on the number of fretting cycles and on the relative displacements between the wires. The immersion in water seems to reduce the cracking damage, for higher strokes.