Impacts of corrosion inhibiting admixture and supplementary cementitious material on early strength concrete

Abstract

This research aimed to evaluate the influence of alccofine 1203 on a mineral admixture and sodium nitrite as a corrosion inhibitor on the properties of concrete. To achieve these aims, an experimental investigation was carried out on a set of composite samples comprising five distinct concrete formulations. Five different mixes for the concrete were used as the overlay materials such as NC as a reference concrete, alccofine concrete (i.e. 25% cement replaced with alccofine), and alccofine concrete with varying dosages of sodium nitrite (i.e. 1%, 1.25%, and 1.5%). Alccofine reduced the workability and water absorption and increased the compressive strength of the concrete (5%) at curing age of 28 days. Adding sodium nitrite further reduced water absorption of the concrete and workability but compressive strength of 29.15% and 26.93% for the curing period of 3 and 7 days, respectively. The pH of the concrete powdered solution became more alkaline with the replacement of alccofine and addition of sodium nitrite. Free chloride content dropped by 48 and 66%, respectively, with the introduction of GGBS and sodium nitrite. Corrosion properties of the concrete samples were examined using open circuit potentials and linear polarization resistance of various concrete mixes after being immersed in 1 M H2SO4 and 3% NaCl environment. The findings indicated a notable improvement in the corrosion resistance, water absorption test, thermal conductivity, strength properties, and microstructural properties of concrete with the incorporation of SN in combination with alccofine. The application of the response surface method allowed for the prediction, validation, and optimization of experimental data using a regression equation.