Performance of Reinforcing Steel in Concrete Containing Silica Fume and Blast-Furnace Slag Ponded with Sodium-Chloride Solution

This paper describes the performance of steel reinforcement in concrete slabs that were ponded with a 3.4% sodium chloride solution for a period of 6 months. The concrete slabs were cast using Portland cement concrete with and without silica fume and blast-furnace slag. The concrete cover to steel reinforcing bars ranged from 13 to 76 mm. The concrete resistance to chloride ion penetration was determined according to ASTM C 1202. The corrosion resistance of the steel reinforcing bars was determined using half-cell potential, linear polarization, and AC impedance techniques. The test results showed that both the silica fume and slag concretes exhibited very low penetrability to chloride ions, with the value of charge passed being less than 1000 coulombs, regardless of the water-cement ratio (w/c).