Implications of grout condition on galvanic coupling and hydrogen absorption within post-tensioned bridge tendons constructed with galvanized steel ducts

Abstract

There has been concern that prestressing structural steel contained within galvanized bridge tendon ducts may become embrittled due to excessive galvanic coupling with the duct of which may be exacerbated by deficiencies within the grout fill. The objective of this work is to quantify the level of galvanic coupling achievable as a function of grout condition and to assess whether such conditions may promote water reduction and hydrogen absorption. Experimental tendon assemblies were used to quantify galvanic coupling considering a single prestressing steel wire and various grout conditions. The results were related to more realistic geometric configurations by simulations considering a range of possible kinetic boundary conditions. A model is used to estimate the amount of hydrogen that may be absorbed as a function of time considering the coupling current density.