Chloride corrosion of steel fibre reinforcement in cement mortar

Abstract

This paper presents an experimental study on the corrosion resistance of steel fibres and steel bar reinforcement in cement mortar. The mortar matrix incorporated various amounts of calcium chloride from 2 to 10%, and the rate of corrosion was monitored by the electrode potential method. The structure of the mortar and the steel surfaces were examined by scanning electron microscopy. The results showed that the addition of calcium chloride modified the microstructure of the mortar matrix, both its water absorption capacity and its porosity increased with increasing amounts of calcium chloride. The electric potential measurements showed that while the bar reinforcement displayed corrosion at 2% calcium chloride, the fibres did not indicate any harmful corrosion until the chloride content was 6%. Chloride admixtures added to concrete may thus be less harmful to steel in steel fibre concrete than in reinforced concrete.