Cation Migration in Mortar with Different Volume Fractions of Aggregate Affected by Electric Field

Abstract:

This study used Type I Portland cement with Na2Oeq 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 (Vf) were adjusted to 0, 10, 20, 30, 40, 50 and 60%, and Acceleration Lithium Migration Technique (ALMT) experiments with 9 A/m2 constant current density were performed. The results show that for specimen with Vf 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 Vf was increased to 20 and 30%, the negative effect from the dilution and the tortuosity effects generated by the increase in Vf was cancelled the positive effect from ITZ on ion migration. When Vf 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 O2, while the cathode produced a small amount of H2.

• Periodical: Applied Mechanics and Materials (Volumes 99-100)
• Pages: 711-714
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.99-100.711
• Online since: September 2011
• Authors: Wen Ten Kuo, Chih Chien Liu, Wei Chien Wang
• Keywords: Aggregate, Alkali-Silica Reaction, Electrochemistry, Lithium, Mortar

References

[1] C.C. Liu, Identify the reactivity of aggregates in Taiwan and using electrochemical techniques to mitigate expansion due to alkali-aggregate reaction in concrete, Ph.D. Thesis, Department of Civil Engineering, National Central University, Taiwan, 2003 (in Chinese).

[2] W.C. Wang, A Study of using one dimensional electrochemical cation migration technique to inhibit concrete ASR, Ph.D. Dissertation, Department of Civil Engineering, National Central University, ChungLi, Taiwan (2010). (in Chinese).

[3] W.C. Wang, C.C. Liu, and C. Lee, "Migration of cations in mortar under an electrical field controlled by a constant current density," Advanced Materials Research, Vols. 150-151 (2011), p.362.

DOI: 10.4028/www.scientific.net/amr.150-151.362