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Durability of mixtures containing calcium nitrite based corrosion inhibitor
AbstractThe influence of calcium nitrite based corrosion inhibitor on the corrosion of reinforcing steel embedded in 14 different mortars is experimentally investigated in this work. Two Portland cements, NPC and SR (type I and V according to ASTM Standards) and 12 blended cements were used. The pozzolanic materials used were three lignite fly ashes, silica fume and one natural pozzolan (Milos' Earth). All blended cements were produced in the laboratory by grinding Portland clinker, gypsum and the appropriate pozzolanic material. One commercially available blended cement (CEM II/A-M 32.5N) was also used in this research. Mortar specimens (cylinders 100×40 mm) were prepared, according to DIN 1164 with and without calcium nitrite and used for measurements of carbonation and chloride-induced corrosion for a time period of 2 years. Chloride resistance was monitored according to ASTM C876 on specimens immersed in a 5% NaCl solution after an initial curing of 28 days. The carbonation depth was measured on cylinders cured in a severe environment using a spray indicator enabling the estimation of different pH values. Results show that calcium nitrite has a beneficial effect in shifting the corrosion potential towards electropositive direction especially in the case of NPC and SR cements. The corrosion potential of blended mixtures was also shifted towards electropositive direction, but since the pozzolanic materials had a beneficial effect by themselves, the reduction was comparative smaller. The beneficial effect of calcium nitrite was also confirmed by the gravimetric weight loss measurements performed after 2 years of immersion in the 5% NaCl solution. Carbonation depth of all mixtures was reduced or remained the same when calcium nitrite was used. Chloride permeability was not seriously influenced by the addition of calcium nitrite, as it is indicated by the total chloride measurements performed after 2 years of immersion in the 5% NaCl solution.
Durability of mixtures containing calcium nitrite based corrosion inhibitor
AbstractThe influence of calcium nitrite based corrosion inhibitor on the corrosion of reinforcing steel embedded in 14 different mortars is experimentally investigated in this work. Two Portland cements, NPC and SR (type I and V according to ASTM Standards) and 12 blended cements were used. The pozzolanic materials used were three lignite fly ashes, silica fume and one natural pozzolan (Milos' Earth). All blended cements were produced in the laboratory by grinding Portland clinker, gypsum and the appropriate pozzolanic material. One commercially available blended cement (CEM II/A-M 32.5N) was also used in this research. Mortar specimens (cylinders 100×40 mm) were prepared, according to DIN 1164 with and without calcium nitrite and used for measurements of carbonation and chloride-induced corrosion for a time period of 2 years. Chloride resistance was monitored according to ASTM C876 on specimens immersed in a 5% NaCl solution after an initial curing of 28 days. The carbonation depth was measured on cylinders cured in a severe environment using a spray indicator enabling the estimation of different pH values. Results show that calcium nitrite has a beneficial effect in shifting the corrosion potential towards electropositive direction especially in the case of NPC and SR cements. The corrosion potential of blended mixtures was also shifted towards electropositive direction, but since the pozzolanic materials had a beneficial effect by themselves, the reduction was comparative smaller. The beneficial effect of calcium nitrite was also confirmed by the gravimetric weight loss measurements performed after 2 years of immersion in the 5% NaCl solution. Carbonation depth of all mixtures was reduced or remained the same when calcium nitrite was used. Chloride permeability was not seriously influenced by the addition of calcium nitrite, as it is indicated by the total chloride measurements performed after 2 years of immersion in the 5% NaCl solution.
Durability of mixtures containing calcium nitrite based corrosion inhibitor
Sideris, K.K. (author) / Savva, A.E. (author)
Cement and Concrete Composites ; 27 ; 277-287
2004-01-01
11 pages
Article (Journal)
Electronic Resource
English
Durability of mixtures containing calcium nitrite based corrosion inhibitor
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