Temperature Influence on Inhibitory Efficiency of Three Phosphate Inhibitors by Mass Loss

The effect of temperature on steel samples immersed in concrete pore solutions contaminated by chlorides incorporating three inhibitors based on phosphate (Na3PO4, K2HPO4, and Na2PO3F) was studied by gravimetric measurements at several ranges: 298, 308, and 318 K. The results obtained for the use of these three products show that the inhibitory efficacy is lower at 318 K than that detected at 308 and 298 K of temperature. Also, we find that the best inhibitory efficiency at 298 K was detected for Na2PO3F (75.80% at 0.05 mol/l of concentration) followed by K2HPO4 (65.05% at 2.5 10−3 mol/l) and then Na3PO4 (61.48% at 7.5 10−3 mol/l)

Effectiveness of corrosion inhibitors in simulated concrete pore solution

International audience10 Steel embedded in concrete is normally in a passive state against corrosion due to a thin iron 11 oxide layer that forms on the steel surface and remains stable in the high alkaline environment 12 of the concrete. This protective film must be destroyed (depassivation) and this can be mainly 13 done in two ways: by the attack of chlorides on the steel (seawater, de-icing salt, unwashed 14 sea sand, admixtures etc.) or by carbonation. Corrosion inhibitors may be a good alternative to 15 protection steel against corrosion due to its lower cost and easy application. Many researchers 16 are inclined to use surface applied corrosion inhibitors and prefer to use the Cl-/inhibitor 17 parameter as an indication of chloride inhibitor threshold level. The objective of this study 18 was to fill the gap left by public research in developing methods of corrosion control of 19 reinforcement in concrete by synthetic solutions to emulate concrete environment. Three 20 inhibitors were distinguished as passivation inhibitors in real solution extract and synthetic. In 21 this study the tests with calcium nitrite (CNI), sodium monoflurophosphate (MFP) and 22 ethanolamine based inhibitors showed reductions in the overall rates of corrosion after the 23 inhibitive treatments. 2