Field Evaluation of Corrosion Inhibitors for Concrete.

Report No: 99-IR1

Published in 1998

About the report:

One hundred and fifty-six exposure slabs have been constructed with and without a variety of combinations of corrosion inhibiting admixtures and topically applied inhibitors. To accelerate corrosion one hundred and thirty-six of the slabs were constructed with concrete that surrounded the top mat of reinforcement with chloride contents of 3,6, 10, and 15 Ib/yd³ (1.8,3.5,5.9, and 8.9 kg/m³). This paper presents the results from measurements made on the slabs in May 1998 after approximately 1 year of exposure. The measurements show that as the chloride ion content in the slabs increases, the macrocell current, macrocell potential, half-cell potential, and rate of corrosion increase and the resistance decreases. Macrocell currents exceed 10 µA, indicating corrosion activity, in slabs cast with chloride in the concrete except those with 3 Ib/yd³ (1.8 kg/m³ ) of chloride that were overlayed and patched or patched. Measurements taken to determine the rate of corrosion indicate high, moderate, low, and passive states of corrosion in 63,22, 12, and 3 percent, respectively, of the slabs. The measurements also show no significant difference between the slabs repaired with and without corrosion inhibitor admixtures and topical treatments. Slabs repaired with 7% silica fume showed half-cell potentials that were less negative than those repaired without silica fume.

Disclaimer Statement:The contents of this report reflect the views of the author(s), who is responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Virginia Department of Transportation, the Commonwealth Transportation Board, or the Federal Highway Administration. This report does not constitute a standard, specification, or regulation. Any inclusion of manufacturer names, trade names, or trademarks is for identification purposes only and is not to be considered an endorsement.

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Last updated: December 13, 2023

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