The thermogalvanic currents between nominally identical segments in a reinforced concrete beam were investigated. Temperature gradients induce galvanic currents that exhibit a 30 degrees C critical point. The character of the hot electrode side changes from anodic to cathodic when the temperature rises above that pivot point. Parallel tests performed in solution using carbon steel-stainless steel galvanic couples also revealed that 30 degrees C is a critical temperature. In NaOH solution the carbon steel behaves cathodically with respect to stainless steel but only for T<30 degrees C. In Ca(OH)(2) solution containing chlorides the carbon steel consistently behaves anodically while the degree of thermogalvanic current exhibits a pronounced temperature dependence. (C) 2015 Elsevier Ltd. All rights reserved.