Effects of Deicers
Sodium chloride: Sodium chloride has little or no effect on properly air entrained concrete but will damage
plants and corrode metal.
Calcium chloride: Calcium chloride in weak solutions has little chemical effect on concrete or vegetation
but does corrode metal, and strong calcium chloride solutions can chemically attack concrete. The
reaction is accelerated by high temperature
Magnesium chloride: A PCA literature search found three references comparing the effects of magnesium
chloride with sodium chloride and other deicers on the scaling resistance of concrete. Unfortunately, the
cited studies provide conflicting results.
The abstract from a German field study (Leiser 1967) states that "concrete surfaces were only slightly
affected [by magnesium chloride lye], and that the solution is less harmful than granulated salt." However,
two recent studies found magnesium chloride to be more aggressive than sodium chloride.
In the first study (Cody 1996), concrete containing dolomite coarse aggregate was cored from five highway
pavements. Small blocks were cut from the cores and subjected to wet-dry and freeze-thaw cycles in
0.75M and 3.0M solutions of NaCl, CaCl2, and MgCl2. Magnesium chloride was the most destructive deicer,
producing severe deterioration under almost all of the experimental conditions. Calcium chloride was the
next most destructive salt. Sodium chloride was relatively benign. In the second study (Lee 2000), the
researchers again found magnesium chloride to be significantly more aggressive than sodium chloride in
wet-dry and freeze-thaw conditions.
In both of these studies, the authors concluded that the major cause of deterioration by magnesium-based
deicers was the formation of non-cohesive magnesium silicate hydrates (MSH), produced by the reaction of
dissolved magnesium with calcium silicate hydrates of the cement. Because MSH does not form strong
bonds with aggregate particles, these phases cause loss of cohesion in portland cement paste and will
promote crumbling. A common finding of the above research is that all deicers can aggravate scaling,
emphasizing the need for placing high-quality, air-entrained concrete in deicer environments.
Urea does not chemically damage concrete, vegetation or metal.
Ammonium: Deicers containing ammonium nitrate and ammonium sulfate should be prohibited because
they rapidly attack and disintegrate concrete. Deicers used in low concentrations (2% to 4% by weight) can
cause more surface scaling than higher concentrations or no deicer at all.
plants and corrode metal.
Calcium chloride: Calcium chloride in weak solutions has little chemical effect on concrete or vegetation
but does corrode metal, and strong calcium chloride solutions can chemically attack concrete. The
reaction is accelerated by high temperature
Magnesium chloride: A PCA literature search found three references comparing the effects of magnesium
chloride with sodium chloride and other deicers on the scaling resistance of concrete. Unfortunately, the
cited studies provide conflicting results.
The abstract from a German field study (Leiser 1967) states that "concrete surfaces were only slightly
affected [by magnesium chloride lye], and that the solution is less harmful than granulated salt." However,
two recent studies found magnesium chloride to be more aggressive than sodium chloride.
In the first study (Cody 1996), concrete containing dolomite coarse aggregate was cored from five highway
pavements. Small blocks were cut from the cores and subjected to wet-dry and freeze-thaw cycles in
0.75M and 3.0M solutions of NaCl, CaCl2, and MgCl2. Magnesium chloride was the most destructive deicer,
producing severe deterioration under almost all of the experimental conditions. Calcium chloride was the
next most destructive salt. Sodium chloride was relatively benign. In the second study (Lee 2000), the
researchers again found magnesium chloride to be significantly more aggressive than sodium chloride in
wet-dry and freeze-thaw conditions.
In both of these studies, the authors concluded that the major cause of deterioration by magnesium-based
deicers was the formation of non-cohesive magnesium silicate hydrates (MSH), produced by the reaction of
dissolved magnesium with calcium silicate hydrates of the cement. Because MSH does not form strong
bonds with aggregate particles, these phases cause loss of cohesion in portland cement paste and will
promote crumbling. A common finding of the above research is that all deicers can aggravate scaling,
emphasizing the need for placing high-quality, air-entrained concrete in deicer environments.
Urea does not chemically damage concrete, vegetation or metal.
Ammonium: Deicers containing ammonium nitrate and ammonium sulfate should be prohibited because
they rapidly attack and disintegrate concrete. Deicers used in low concentrations (2% to 4% by weight) can
cause more surface scaling than higher concentrations or no deicer at all.
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