Chloride permeability and chloride-induced corrosion of concrete containing lithium slag as a supplementary cementitious material
Md Tanvir Ehsan Amin, Prabir Kumar Sarker, Faiz Uddin Ahmed Shaikh, Anwar Hosan
Abstract
The durability of concrete structures in marine environments is often compromised by chloride penetration which accelerates the corrosion of reinforcing steel. As supplementary cementitious materials (SCMs) are widely used to reduce chloride penetration in concrete, this study introduces lithium slag (LS) as an emerging SCM at 20–60 % replacement of cement. To assess its impact on chloride penetration and corrosion resistance, RCPT, chloride diffusion test and accelerated corrosion tests were conducted. The results showed that LS significantly reduced chloride penetration even at higher cement replacement levels (40–60 %) and the chloride ion penetration decreased by 76–78 % compared to that of the control mix. Among the mixes, 40 % cement replacement by LS showed the best performance with reduced rebar corrosion rates, higher electrical resistance, and lower chloride penetration over time due to its compact structure and reduced porosity. In addition, the 40LS mix also reduced the mass loss of steel bar by 25 % and crack width by 48 % in the accelerated corrosion test. Finally, the chloride diffusion coefficient was found 30 %, 49 %, and 14 % lower for the 20LS, 40LS, and 60LS samples, respectively, compared to that of the control sample. The findings demonstrate that LS is an effective SCM for enhancing chloride resistance and mitigating reinforcement corrosion in concrete. • RCPT value decreased extensively with increment of LS (20–60 %) as SCM. • Notable 48.8 % reduction in chloride diffusion coefficient (0–20 mm) observed by using 40 % LS as SCM. • 20–40 % usage of LS as SCM delayed corrosion initiation and mitigated corrosion-induced cracks. • Higher concrete resistivity found with lower pore solution conductivity using LS (20–60 %).