Evaluating corrosion resistance of recycled aggregate concrete integrating ground granulated blast furnace slag

• Published in: Construction & building materials 2023-03, Vol.370, p.130676, Article 130676
• Main Authors: Shankar Biswal, Uma, Dinakar, Pasla
• Format: Article
• Language: English
• Subjects: Carbonation; Chloride migration; Corrosion; Half-cell potential; Potentiodynamic polarization; Recycled aggregate; Surface Resistivity
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2023.130676

•Lower compressive strength was observed for GGBS based RAC mixes at early ages and at later ages comparable CS was obtained.•Resistivity increased almost two times with the inclusion of GGBS.•As expected, GGBS based RAC showed greater carbonation depths.•Inclusion of GGBS increased the resistance to chloride ion migration.•The corrosion rates for GGBS based RAC were almost half that of the OPC based RAC. By understanding the importance of recycled aggregates in the development of sustainable environment, the present study investigated the corrosion performance of recycled aggregate concrete. Since the water to binder ratio has a substantial impact on the performance of concrete, corrosion studies was conducted on a wide spectrum of water to binder ratio varying from 0.25 to 0.75 at 0.1 intervals. In addition, the impact of 50 % ground granulated blast furnace slag on corrosion performance was investigated for the same range of water to binder ratio. For all these developed concretes, coarse natural aggregates were totally replaced with coarse recycled aggregates and their corrosion performance was explored through surface resistivity test, accelerated carbonation test, rapid chloride migration test, half-cell potential, and corrosion rate test. From the results it can be concluded that the inclusion of ground granulated blast furnace slag into the recycled aggregate concrete mix 1) achieved 70 MPa compressive strength in 90 days of curing 2) increased the surface resistivity to 88 kΩcm and 3) decreased the carbonation resistance. By accessing the real time corrosion resistance of steel inside the concrete, an increase in potential and decrease in corrosion rate was observed for ground granulated blast furnace slag based concrete. Hence, it can be concluded that the inclusion of ground granulated blast furnace slag in the recycled aggregate concrete mixes increased the corrosion resistance.