Effect of salt additives on concrete degradation (Phase II). Executive summary

725559PDFResearch PaperMN/RC-96/10Deicing chemicalsConcreteChemical reactions and processesCorrosionHighway maintenanceDeteriorationMinnesotaMinnesota. Dept. of TransportationJang, Ji-WonIwasaki, IwaoWeiblen, PaulNTL-HIGHWAY/ROAD TRANSPORTATION-Construction and MaintenanceNTL-HIGHWAY/ROAD TRANSPORTATION-MaterialsNTL-HIGHWAY/ROAD TRANSPORTATION-Pavement Management and PerformanceUS Transportation CollectionThis research builds on a previous investigation, which found that corrosion-inhibitor-added deicing salts caused degradation of concrete by both anions and cations. The latest research phase looked at methods to detect the chemical reactions between concrete and corrosion-inhibitor-added deicing salts, and to determine the chemical compositions of the precipitates formed by chemical reactions between concrete and the corrosion-inhibitor-added deicing salts. The research led to the following conclusions: a simple method was developed for the detection of chemical reactions between deicing chemicals and concrete; the results provided clear evidence of the chemical reactions between concrete and the corrosion-inhibitor-added deicing salts; the different amounts of precipitates (chemical reaction products) found in the test cells were dependent on the type and concentration of corrosion-inhibitor-added deicing salts; precipitates formed by chemical reactions between deicing chemicals and concrete were identified by using chemical analysis, scanning electron microscopy, and X-ray diffraction analysis; and precipitates were calcium and/or magnesium phosphates as a major component, and gypsum as a minor component. 4 Tables, 2 figures, 2 photos, references. 6,626k, 30p