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).Ce document d\ue9crit la performance des armatures d?acier dans des dalles de b\ue9ton que l?on a immerg\ue9es dans une solution de chlorure de sodium \ue0 3,4 % pendant six (6) mois. Les dalles avaient \ue9t\ue9 coul\ue9es avec du ciment Portland, avec et sans fum\ue9es de silice et laitier de haut fourneau. L?\ue9paisseur d?enrobage des barres d?armature d?acier dans le b\ue9ton allait de 13 \ue0 76 mm. L?imperm\ue9abilit\ue9 du b\ue9ton aux ions chlore a \ue9t\ue9 d\ue9termin\ue9e suivant la norme ASTM C 1202. La r\ue9sistance \ue0 la corrosion des barres d?armature d?acier a \ue9t\ue9 \ue9tablie par relev\ue9 de potentiel par demi-pile de la polarisation lin\ue9aire et des techniques d?imp\ue9dance \ue0 courant alternatif. Les r\ue9sultats des \ue9preuves ont r\ue9v\ue9l\ue9 que tant les b\ue9tons de fum\ue9es de silice que ceux de laitier affichaient une p\ue9n\ue9trabilit\ue9 tr\ue8s faible aux ions chlore, la valeur de la charge accept\ue9e \ue9tant inf\ue9rieure \ue0 1000 C, et ce ind\ue9pendamment du rapport eau de g\ue2chage-ciment.Peer reviewed: YesNRC publication: Ye