Experimental observations of stray current effects on steel fibres embedded in mortar

• Customised specimens with steel fibres or rebars were subjected to direct stray current.
• The conditions required to circulate current in the fibres/rebars were investigated.
• The length of the reinforcement is the predominant requirement for current transfer.
• The risk of stray current induced corrosion of steel fibre reinforced concrete is very low in real structures.

It is known that stray direct current can cause corrosive damage over time to bar reinforced concrete, but knowledge on the consequences to steel fibre reinforced concrete is limited. This paper presents analyses and corresponding results from an experimental program (parametric study) investigating the conditions required for current to be picked up by embedded steel fibres or reinforcement (rebars). The experiments showed that there is a clear ‘length effect’ related to the susceptibility of stray current being picked up by embedded steel (fibres or rebars): the shorter the reinforcement, the larger potential gradient between anode and cathode is required.