Effect of Electrochemical Penetration of Lithium Ions on Concrete Expansion Due to ASR

抄録

Concrete expansion due to alkali-silica reaction (ASR) is one of the serious deterioration mechanisms of concrete structures. However, no promising repair method for ASR has been established yet. In a bid to remedy this situation, an electrochemical technique to accelerate the penetration of the lithium ions (Li⁺) in a lithium-based electrolyte solution into concrete has been developed for the purpose of suppressing ASR-induced expansion due to Li⁺. From the results of past research work, the penetration area of Li⁺ is limited around the concrete surface and it is difficult to make Li⁺ penetrate into the deeper part of concrete.
In this study, experimental investigation was carried out aiming to grasp the influence of the kinds of lithium salts and the temperature of the electrolyte solution on the migration properties of ions in concrete and ASR-induced expansion of concrete. The electrochemical migration of Li⁺ was found to accelerate with rises in temperature and the effective diffusion coefficient of Li⁺ increased three times with changes in temperature from 20°C to 40°C in the case of a Li₂CO₃ electrolyte solution. Moreover, ASR-induced expansion of concrete after this treatment was suppressed compared with the case of non-treated specimens.