Percent calcium chloride, chloride ion, soluble chloride what does it all mean? The mix designer usually speaks of adding an amount of calcium chloride that is a certain percent of the weight of cement in the concrete. Those who study corrosion of reinforcing steel are concerned with the amount of chloride ion, particularly the soluble chloride ion, per cubic yard of concrete. It is important to distinguish between these two values, and to learn how they are related.

As an accelerator, calcium chloride acts on the setting and hardening of cement. The amount of calcium chloride needed depends on the amount of cement used, so the mix designer talks about calcium chloride content as a percent by weight of cement. Chemists and engineers are concerned with the amount of chloride ion per cubic yard of concrete because the chloride ion concentration can affect the rate of corrosion. If you are working under chloride ion limitations/restrictions, read carefully to be sure which way the limits are stated some are expressed as a percentage by weight of cement and others have been stated in parts per million of concrete.