Cation migration in mortar with different volume fractions of aggregate affected by electric field

This study used Type I Portland cement with Na ₂O _eq of 0.67% to fabricate a mortar specimen with w/c ratio of 0.5 and a dimension of φ10 ×?3 cm. The 7 volume fractions of aggregate (V _f) were adjusted to 0, 10, 20, 30, 40, 50 and 60%, and Acceleration Lithium Migration Technique (ALMT) experiments with 9 A/m ₂ constant current density were performed. The results show that for specimen with V _f of 10%, the negative effects on ion migration generated by aggregate dilution and tortuosity effects were the greatest; therefore, the removal times of Na ⁺ and K ⁺, the time it took for Li ⁺ to pass through the specimen and the time for Li ⁺ to reach steady state were all longer than in the other experiments. When V _fwas increased to 20 and 30%, the negative effect from the dilution and the tortuosity effects generated by the increase in V _f was cancelled the positive effect from ITZ on ion migration. When V _f was increased to over 30%, the percolation effect from ITZ controlled the behavior of ion migration. During the ALMT experiment, the anode steadily produced a large amount of O ₂, while the cathode produced a small amount of H ₂.