"Antifreeze" is a misnomer applied to admixtures for cold weather mortar that are really accelerators, and not depressants of the mortar freezing point. These mixtures may decrease the compressive and bond strengths of the masonry if they are used in quantities that significantly lower the freezing point in the mortar. Antifreeze compounds have little benefit and are not recommended. Accelerators may reduce the time that newly constructed masonry needs to be protected from cold temperatures, but they do not eliminate the need for such protection.

Accelerators normally used include soluble carbonates, silicates and fluosilicates, aluminous cements, calcium aluminate, and some organic compounds such as triethanolamine. Calcium chloride is sometimes used as an accelerator, but may produce side-effects such as corrosion of steel (reinforcement, ties, anchors). For that reason, calcium chloride should not be permitted for use in mortar.

Corrosion inhibitors in accelerators are not recommended because they have not been evaluated in cold weather masonry construction.

Air-entraining admixtures can increase mortar workability and impede freeze/thaw deterioration. However, an excessive amount of air-entrainment should not be used in cold weather masonry construction because it will result in lower compressive strength and lower bond strength.

Coloring agents should be limited to finely ground metallic oxides, in quantities that do not exceed 10% of the cement content by weight. Carbon black, if used, should be limited to 2% of the cement content by weight.

 
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