EFFECT OF SODIUM NITRITE AS A CORROSION INHIBITOR ON WORKABILITY AND STRENGTH DEVELOPMENT OF CONCRETE
Authors: *Ogirigbo O.R, Ezekiel K.A, Duru F, Owolabi R
The use of corrosion inhibitors as admixtures in the Nigerian construction industry is gradually becoming a common practice. However, studies relating to how these admixtures affect the properties of concrete are very few. This study investigated the effect of sodium nitrite - a type of corrosion inhibitor - on some properties of fresh and hardened concrete. Two different concrete mixes (C20 and C25) were prepared. Sodium nitrite was added in dosages of 0.3, 0.6 and 1.0% of the mixing water. The fresh concrete mix was tested for workability by performing a slump test, while compressive strength was determined on the hardened concrete at 7, 14 and 28 days. The results obtained showed an increase in workability when sodium nitrite was added at dosages below 0.6%, and a decrease at dosages of 1.0%. The compressive strength of concrete dosed with 0.6% sodium nitrite recorded after 7 days was similar to that of concrete without sodium nitrite. However, after 28 days, concrete mixes dosed with sodium nitrite had lower strengths compared to those without sodium nitrite. This was attributed to increased alkali-aggregate reaction and was seen to be more pronounced on the C20 concrete, which contained a higher proportion of aggregates.
Affiliations: Department of Civil Engineering, Faculty of Engineering, University of Benin, PMB 1154, Benin City, Nigeria
Keywords: Sodium Nitrite, Slump, Compressive Strength, Corrosion Inhibitor, Concrete
Published date: 2016/12/30