Methods of ASTM G16 and conflicts in corrosion test data: Case study of NaNO2 effectiveness on steel-rebar corrosion

In this paper, applications of the methods of ASTM G16 for addressing inherent conflicts in laboratory measurements of corrosion test data were studied, using the inhibiting effect of NaNO2 on the corrosion of concrete steel-rebar for the case study. For this, electrochemical monitoring techniques were employed for studying effectiveness of different concentrations of NaNO2 admixture in replicated concrete samples immersed in NaCl and in H2SO4 media for an experimental period of sixty-eight days. The corrosion test data from this experimental setup were subjected to the probability density fittings of the Normal and the Weibull functions as well as to significance testing methods of ASTM G16-99 R04 specifications. Results identified 10g (0.1208M) NaNO2 admixture with optimal inhibition efficiency model, η = 88.38±4.62%, in the saline/marine simulating environment and the 8 g (0.0966M) NaNO2 admixture with optimum effectiveness, η = 13.51±83.48%, in the acidic environment. The techniques of ASTM G16 adequately identified and addressed conflicting effectiveness from the test data of NaNO2 admixtures in the studied test environments. joshua.okeniyi@covenantuniversity.edu.n