Behavior of cations in mortar under accelerated Lithium Migration Technique controlled by a constant voltage

The Accelerated Lithium Migration Technique (ALMT) is an electrochemical method to remove Na⁺ and K⁺ from concrete, and simultaneously drive Li⁺ into concrete to inhibit alkali-silica reaction (ASR). This study investigates the relationship between the applied voltage and the migration behavior of cations related to ASR. The results show that after the completion of Na⁺ and K⁺ removal, migration of Li⁺ begins to enter a steady state. With the increase in applied voltage, the removal rate and removable amount of alkalis increases, the required time of alkalis removal and the time for Li⁺ to pass through the specimen decreases, and the migration coefficients of Li⁺ increase. Furthermore, the above migration parameters of cations have positive linear relationships with the average current density. After the ALMT process, the average Li/(Na + K) molar ratio of the specimen is sufficiently large to mitigate ASR problems.