Application of segmented rebars for studying corrosion of steel in concrete

摘要

Segmented rebars consisting of one mild steel segment in between two stainlesssteel segments were used to study steel corrosion in concrete. In total four differentmild steel segment lengths were tested: 5 mm (exposed area 157 mm~2), 10 mm (314mm~2), 20 mm (628 mm~2) and 50 mm (1570 mm~2). The rebars were embedded in achloride contaminated concrete (2.5 % Cl- by cement weight) which was exposed toa high relative humidity (95-98 %) and a temperature around 20 °C. The corrosionprocess was monitored over several months during which the segments were periodicallyconnected. The galvanic current between the corroding mild steel segmentsand the passive stainless steel segments was measured. The results were comparedto linear polarization resistance measurements. In the experiment, the galvanic currentwas just half as high as the corrosion current determined by LPR for the smallestmild steel segment length and only 5 % in case of the biggest segment.