A Study on Sodium Nitrite, Zinc Oxide and Di-Sodium Hydrogen Phosphate as Corrosion Inhibitors in Reinforced Concrete

Author(s): Rozampuia, Jyotish Kumar Das and Bulu Pradhan
Paper category: Proceedings
Book title: Proceeding of the 71st RILEM Annual Week & ICACMS 2017
Editor(s): Manu Santhanam, Ravindra Gettu, Radhakrishna G. Pillai, Sunitha K. Nayar
ISBN:978-2-35158-195-7, 978-2-35158-190-2 (Set)
e-ISBN: 978-2-35158-191-9
Publisher: RILEM Publications SARL
Publication year: 2017
Pages: 385-394
Total Pages: 10
Language : English

Abstract: Corrosion of steel is one of the most extensive forms of deterioration of concrete structures, which are exposed to chloride environment and/or affected by carbonation. Thus, steel reinforcement in concrete structures must be protected from corrosion to extend service life of these structures. In this paper, inhibition effectiveness of three corrosion inhibitors viz., sodium nitrite, zinc oxide, and di-sodium hydrogen phosphate in preventing chloride induced steel reinforcement corrosion in concrete was studied. Cube specimens for 28-days compressive strength and prismatic reinforced concrete specimens for half-cell potential and linear polarization resistance measurements were prepared using ordinary Portland cement at w/c ratio of 0.50. The inhibitors were added at dosages of 1 and 3% by weight of cement during the preparation of concrete mixtures. After 28 days of curing, prismatic reinforced concrete specimens were exposed to chloride solutions containing different concentrations of sodium chloride (1, 3 and 5%). From the results, it is observed that zinc oxide and di-sodium hydrogen phosphate (DHP) improved the compressive strength whereas, sodium nitrite slightly reduced the compressive strength of concrete as compared to control mix. All the three corrosion inhibitors mostly showed less negative half-cell potential and lower corrosion current density as compared to control mix.

Online publication :2017
Publication type :full_text
Public price (Euros) : 0.00