Use of sodium molybdate in reinforced concrete exposed to chlorides

Author(s): D. R. da Silva, H. S. Júnior, A. C. Vieira da Nóbrega, M. V. V. Almeida de Sá
Paper category: Workshop
Book title: International RILEM Workshop on Integral Service Life Modelling of Concrete Structures
Editor(s): R.M. Ferreira, J. Gulikers, C. Andrade
Print ISBN: 978-2-35158-058-5
e-ISBN: 978-2-35158-090-5
Publisher: RILEM Publications SARL
Pages: 359 - 366
Total Pages: 8
Language: English

Abstract: 
In order to prevent corrosion problems which are becoming more and more common in engineering reality we propose to add the corrosion inhibitor sodium molybdate to minimize or to delay the beginning of the corrosion reactions. It was used a mixture proportions of 1.0:1.5:2.5 (cement, sand and stone), superplastifier 2% and water/cement ratio 0.40, additioned of the sodium molybdate in the proportion of 0.5 to 3.5% related to the cement weight. The steel corrosion process was evaluated using electrochemical techniques and was studied the influence of this addition on the fresh and hardened concrete properties. The inhibitor didn’t influence the compressive strength and the water absorption. The workability was reduced, but it showed a 100mm at its critic point at 2% addition, showing efficiency. Concerning the polarization resistance, after the 68th day the 2% sodium molybdate showed corrosion density around 0.19 μA/cm2, standing under this level until the 336th day when it was around 0.18 μA/cm2, showing a better performance than the reference concrete, since it after the 30th day showed corrosion density around 0.40 μA/cm2. The corrosion potential along the time showed that the despassivation occurred after around the 430th day in contrast to the 230th day of the reference concrete.

Keywords: concrete, corrosion inhibitor, sodium molybdate, electrochemical measurements.

Online publication: 2013
Publication Type: full_text
Public price (Euros): 0.00