USING HUMECTANTS TO ENHANCE THE PERFORMANCE OF EMBEDDED GALVANIC ANODES

摘要

Embedded galvanic anodes are small puck-shaped devices used to provide sacrificial corrosionrnprotection to the reinforcing steel in concrete structures. The anodes consist of a zinc core surroundedrnby a cementitious matrix. The addition of humectants to the mortar shell has been shown to increase thernanode's electrical current output significantly. A large variety of chemical additives can be used tornperform this function, however some may have detrimental side effects. In this study, the current outputrnof a standard anode without humectant is compared against the output of anodes containing halide andrnnon-halide type humectants. The anodes were identical in other respects, and were cast into concreterntest slabs to simulate a field installation. The halide humectant generated the largest current output, andrnthe control generated the least. However, while the halide salt yielded the most favorable results, it isrnpotentially very damaging to reinforcing steel and may not prove to be a suitable candidate. Morernbalanced options including the use of non-halide humectants and modified anode size and configurationrnhold promise, but require further examination to determine their long-term effect on anode output.