This study investigates effect of different concentrations of ethylenediaminetetraacetic disodium dihydrate (EDTA-Na₂: C₁₀H₁₄N₂Na₂O₈.2H₂O) and sodium nitrite (NaNO₂) admixtures, individually or in synergistic/partial NaNO₂ replacement model, on the corrosion of concrete steel-rebar in NaCl and in H₂SO₄ media. Electrochemical monitoring techniques were employed for 48 steel-reinforced concrete samples immersed in the saline/marine and microbial/industrial simulating test environments for 96 days. These test data were subjected to the analyses of the Normal and the Weibull distribution fitting models, for each of which goodness of their fitting the electrochemical test data were studied using the Kolmogorov–Smirnov test statistics. Analysed results showed that EDTA-Na₂ admixture concentrations exhibited better inhibition effectiveness, with relatively good effectiveness in their synergistic admixtures, than their equal-mass NaNO₂ counterparts in both corrosive environments. Also, post-electrochemical experiment subjection of the concrete samples to testing and analyses of ASTM C39/C39M-03 and ASTM C267-01 showed that use of the optimally inhibiting 8 g EDTA-Na₂ (per 2 × 10^–3m³ concrete) culminates in gross reduction in compressive strength of concretes in both test-media. However, lowered EDTA-Na₂ concentrations exhibited better strength improvements with high corrosion inhibition in the test environments. These suggest suitability of EDTA-Na₂ as an environmental-friendly NaNO₂ alternative for inhibiting steel-rebar corrosion in saline/marine and microbial/industrial environments.