CORROSION INHIBITORS IN CONCRETE

摘要

This report discusses the behavior of various corrosion inhibitors for steel in concrete. Three commercially available inhibitors (two based on organic compounds and one calcium nitrite-based) were selected for detailed examination. Each inhibitor was evaluated in several types of concrete mix designs. The mixes included Portland cement concrete as the control, concrete admixed with silica fume, and concrete admixed with fly ash for comparison. Non-destructive tests in progress of steel- reinforced concrete laboratory specimens are used to identify the time at which corrosion of the reinforcement initiates. Standard specimens containing either of the two organic corrosion inhibitors performed relatively equal to control specimens (Type II cement, no pozzolans, no inhibitors). Standard specimens containing the calcium nitrite-based inhibitor showed improved performance. However, specimens containing silica fume exhibit no corrosion activity to date. Based on current data, the calcium nitrite-based inhibitor was effective in mitigating corrosion in high permeability concretes. However, low-permeability concrete specimens containing pozzolans (particularly silica fume) continue to exhibit a significantly longer time to corrosion initiation than specimens containing only conventional corrosion inhibitors.