Corrosion of Reinforced Concrete

Title :
Damaging effects of deicing chemicals on concrete materials

Authors :
Kejin Wanga, Daniel E. Nelsena, Wilfrid A. Nixonb

Abstract :

The damaging impact of various deicing chemicals and exposure conditions on concrete materials was investigated. Five deicing chemicals (sodium chloride, calcium chloride with and without a corrosion inhibitor, potassium acetate, and an agricultural product) were studied. Freezing–thawing (F–T) and wetting–drying (W–D) exposure conditions were considered. Mass loss, scaling, compressive strength, chemical penetration, and micro-structure of the paste and concrete subjected to these deicing chemicals and exposure conditions were evaluated. Results indicated that the various deicing chemicals penetrated at different rates into a given paste and concrete, resulting in different degrees of damage. Among the deicing chemicals tested, two calcium chloride solutions caused the most damage. Addition of a corrosion inhibitor into the calcium chloride solution delayed the onset of damage, but it did not reduce the ultimate damage. Chloride-related deicing chemicals often brought about leaching of calcium hydroxide, as well as chemical alterations in concrete. Potassium acetate caused minor scaling, associated with alkali carbonation of the surface layer of concrete. Although producing a considerable number of micro-pores on the surface of the samples, the agricultural deicing product resulted in the least chemical penetration and scaling damage of paste and concrete.

Keywords :
Deicing, Freezing–thawing, Mass loss, Scaling, Strength, Wetting–drying

Source :
http://www.sciencedirect.com/science/article/pii/S0958946505001010