Corrosion Behavior Of Prestressed Anchor Cable Structures

Corrosive mediums (particularly chloride and sulfate medium) with water aretypically found in the working environment of a prestressed anchor cable. The anchorcable structure itself possesses certain characteristics such as complex details, highworking stress, extremely difficult control in construction, and high hidden operationin construction and maintenance. Thus, corrosion is the key problem related to anchorcables in application. Existing relevant research mainly focuses on the corrosion type,the basic corrosion principle, and the corrosion development law of anchor cables atthe qualitative level. In this paper, the corrosion behavior of the interior bond sectionand the head of a prestressed anchor cable under chloride and sulfate attack is studiedthrough long-term systematic experiments and theoretical analysis.The tensile performance degradation problem of the interior bond section of an-chor cable under chloride environment is studied through long-term systematic ex-periments and theoretical analysis. Several serial time-varying models, such as in-stantaneous corrosion rate, weight loss rate of corrosion, and tensile capacity in thecase of both little oxegen and local oxegen, are established based on the Hill function.Four factors, namely, chloride salt concentration, pore water saturation oxygen stateand concrete strenghth, are set as the independent variables in the models.The bond behavior degradation of the interior bond section of anchor cable underchloride and sulfate environment is studied through long-term systematic experimentsand theoretical analysis. Several factors, namely, corrosion of anchor cable, sulfatesalt concentration and the bond stress constraints etc. The result shows that corrosionof steel strand has a promoting effect to the ultimate bond strength while the corrosionof sulfate on the slurry will reduce the ultimate bond strength, and what is more, theultimate bond strength decreased with the increase of sulfate concentration, the cir-cumferential confinement effect from the rock can significiently improve the ultimatebond strength.The corrosion problems of head of the prestressed anchor cable structure underchloride environment is studied through long-term systematic experiments and theo-retical analysis. Several factors, namely, chlorine salt concentration, thickness of pro-tection layer, effective prestress and. The result shows that to some extent local corro-sion exist in all parts of anchor head, and the crevice corrosion effect is relativelyweak but greater influence on the galvanic corrosion.Combined with the previous research conclutions and theoretical analysis we al- so did some research on the prediction of the whole life working state of prestressedanchor cable structure.