C₁₀H₁₈N₂Na₂O₁₀ inhibition and adsorption mechanism on concrete steel-reinforcement corrosion in corrosive environments

Peer review under responsibility of University of Bahrain.

Figures & data

Table 1 Concentrations in wt% of C₁₀H₁₈N₂Na₂O₁₀ admixtures in steel-reinforced concrete samples.

S/no	Specimen by C10H18N2Na2O10 concentration	S/no	Specimen by C10H18N2Na2O10 concentration
1	0% C10H18N2Na2O10 (blank in NaCl)	2	0% C10H18N2Na2O10 (blank in H2SO4)
3	0% C10H18N2Na2O10 (blank in NaCl_Dup)	4	0% C10H18N2Na2O10 (blank in H2SO4_Dup)
5	0.0833% C10H18N2Na2O10 in NaCl	6	0.0833% C10H18N2Na2O10 in H2SO4
7	0.0833% C10H18N2Na2O10 in NaCl_Dup	8	0.0833% C10H18N2Na2O10 in H2SO4_Dup
9	0.1667% C10H18N2Na2O10 in NaCl	10	0.1667% C10H18N2Na2O10 in H2SO4
11	0.1667% C10H18N2Na2O10 in NaCl_Dup	12	0.1667% C10H18N2Na2O10 in H2SO4_Dup
13	0.25% C10H18N2Na2O10 in NaCl	14	0.25% C10H18N2Na2O10 in H2SO4
15	0.25% C10H18N2Na2O10 in NaCl_Dup	16	0.25% C10H18N2Na2O10 in H2SO4_Dup
17	0.3333% C10H18N2Na2O10 in NaCl	18	0.3333% C10H18N2Na2O10 in H2SO4
19	0.3333% C10H18N2Na2O10 in NaCl_Dup	20	0.3333% C10H18N2Na2O10 in H2SO4_Dup
21	0.4167% C10H18N2Na2O10 in NaCl	22	0.4167% C10H18N2Na2O10 in H2SO4
23	0.4167% C10H18N2Na2O10 in NaCl_Dup	24	0.4167% C10H18N2Na2O10 in H2SO4_Dup
25	0.6667% C10H18N2Na2O10 in NaCl	26	0.6667% C10H18N2Na2O10 in H2SO4
27	0.6667% C10H18N2Na2O10 in NaCl_Dup	28	0.6667% C10H18N2Na2O10 in H2SO4_Dup

Figure 1 Graphical plots of Weibull mean of electrochemical test-data from steel-reinforced concretes (a) half-cell potential (HCP) (b) electrochemical cell current (ECC) (c) corrosion rate (d) corrosion rate for samples in NaCl medium without the blank samples (e) corrosion rate of samples in H₂SO₄ medium including the blank samples in the medium.

Figure 2 Kolomogorov-Smirnov goodness-of-fit (K-S GoF) test results of the Weibull fittings of the test-data from steel-reinforced concrete samples in corrosive environments.

Figure 3 Plots of student’s t-test statistics for significance of differences between replicates of steel-reinforced concrete samples (a) in NaCl medium (b) in H₂SO₄ medium.

Figure 4 Inhibition efficiency ranking of C₁₀H₁₈N₂Na₂O₁₀ admixtures on concrete steel-reinforcement corrosion (a) in NaCl medium (b) in H₂SO₄ medium.

Table 2 Estimated parameters for models of adsorption isotherm.

Medium	Isotherm model	R^2	1/y	1/λ	Equilibrium constant Keq ≡ Kads	RL	(kJ/mol)
NaCl	Langmuir	0.9999			1.0526 × 10^6	1.8945 × 10^–7	–102.7236
	El-Awady	0.1371	3.2522		6.1944 × 10^11		–179.0361
	Freundlich	0.1278		2.426 × 10^–4	1.00003
H2SO4	Langmuir	0.9520			385.8963	1.2774 × 10^–2	–57.2803
	El-Awady	0.4260	1.3463		300.7450		–55.8483
	Freundlich	0.5842		0.2032	1.6864