How Do De-icing Materials Affect Concrete?

Specimens subjected to temperature cycles and wet-dry cycles in 1.06 molal ion concentration NaCl and CaCl 2 solutions (Fig. 1 and 2, respectively) show few signs of damage. The only apparent change is a slight discoloration of the CaCl 2 specimens (Fig. 2).

Specimens subjected to MgCl 2 and CMA solutions exhibited signs of damage, as shown in Fig. 3 and 4, respectively. The MgCl 2 specimens (Fig. 3) were subjected to wet-dry cycles for 80 weeks, after which the test was terminated because the modulus of elasticity had dropped below 90% of its initial value. The CMA specimen (Fig. 4) completed 95 weeks of wet-dry cycling.

The specimens subjected to 6.04 molal ion concentration CaCl 2 and MgCl 2 solutions (Fig. 5 and 6) had the most damage, with a loss of material from the ends and edges of the specimens and some delamination. The damage appears to be the result of both physical damage due to crystal formation in the concrete pores and chemical changes in the cement paste.

The specimens subjected to the 6.04 molal ion concentration CMA solution (Fig. 7) exhibited a nearly uniform loss of material on all exposed surfaces, a change that appears to result primarily from chemical changes in the cement paste.

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