Corrosion Studies on XD3 Reinforced Concrete Samples Prepared by Using
Calcium Nitrate as Inorganic Corrosion Inhibitor with different
superplasticizers
Abstract
This research paper presents an analysis of the corrosion properties of
steel-reinforced concrete samples during immersion in 3.5wt.% NaCl
aqueous solution by measuring their response both cathodic and anodic
polarization in order to determine the corrosion rates in the function
of their calcium nitrate inhibitor content. This cheap inorganic
inhibitor was added to the concrete mix in concentrations of 1% and 3%
by weight of cement in addition to two different superplasticizers
(MapeiDynamon SR 31 and Oxydtron). The compressive strengths of the so
prepared samples were also checked according to the relevant European
standard and were within the acceptable limits, so this inhibitor does
not weaken this important property of the concrete samples. The test
results on steel reinforced samples immersed in 3.5wt.% NaCl aqueous
solutions at room temperature showed promising corrosion mitigating
effects just after 6 months testing period. After 6 months the lower
corrosion currents (i.e. better corrosion resistance) for both types of
superplasticizers were observed with those samples which contained 3%
calcium nitrate inhibitor. The best result was observed with sample C4
(in this case 3% calcium nitrate was added to the mixture of
cement+Oxydtron superplasticizer). The advantageous inhibition mechanism
of nitrate anions is also discussed and interpreted.