Streustromkorrosion von Stahlfaserbeton

The trend toward sustainability also demands a reduction of CO2-intensive materials such as steel in tunnel construction. In this context, fiber-reinforced concrete, particularly steel fiber-reinforced concrete, presents a promising alternative. Due to the electrical conductivity of the steel fibers, the evaluation of stray current corrosion becomes relevant, not only in reinforced concrete, although there are currently no normative regulations in Austria. Stray current corrosion occurs due to unwanted electrical currents, which can cause corrosion in concrete structures with steel reinforcements. Tunnel constructions with direct current-powered tramways are particularly affected. To investigate stray current corrosion in steel fiber-reinforced concrete, the principle of percolation was applied, which describes the transition from insulating to conductive behavior depending on the fiber content. This process determines the so-called percolation threshold. Experimental studies, conducted as part of a research project and a bachelor’s thesis, showed that the percolation threshold is higher than theoretically expected, at fiber contents exceeding 125 kg/m³. Below this threshold, electrical conductivity remained low, indicating a minimal risk of stray current corrosion. An adjusted value was proposed for calculating the stray current risk, though further investigations are necessary for precise validation.