A study on corrosion inhibitors for concrete application

The inhibiting behavior of many organic and inorganic substances against st eel corrosion was evaluated in an alkaline chloride solution, constituted b y a saturated calcium hydroxide solution containing 0.1 M chloride ions. Be sides 0.05 M sodium nitrite (SN), among the tested substances, only 0.005 M 5-hexyl-benzotriazole (C6BTA), 0.05 M sodium beta-glycerophosphate (GPH), and saturated dicyclohexylammonium nitrite (DCHAMN) were able to prevent pi tting corrosion over 30-day exposures to the aggressive electrolyte. Moreov er, very good results were obtained with steel specimens coated by DINITROL AV 30(R), which is a commercial corrosion inhibitive filming product. Chlo ride-polluted mortars embedding steel rods were also prepared to assess the influence of the most promising inhibitors, added either as admixtures or as impregnation agents, under conditions closer to those experienced in con crete. The inhibiting efficiencies (IE) were tested by Electrochemical Impe dance Spectroscopy (EIS). Good results were obtained with admired tungstosi licic acid (TSAH), with GPH or DCHAMN penetrated from the outside or in the presence of DINITROL AV 30(R) coating. (C) 2000 Elsevier Science Ltd. All rights reserved.