Recently, Committee 212 of the American Concrete Institute (ACI) published "Admixtures for Concrete," which echoes the ACI 201 document "Guide to Durable Concrete." The position seemingly taken by these significant ACI Committees is that while chloride of itself does not cause corrosion it furnishes the electrolyte which, with moisture and oxygen, allows corrosion to proceed. Recognizing that it is impractical to suggest chloride-free concrete the two ACI documents give practical limits which should be of benefit to owners of concrete structures.
It has been suggested that concrete producers test their materials to learn how much chloride ion is present from all sources such as aggregates, cement, water and admixtures. It has been further suggested that admixture suppliers be required to show in their literature and on their product labels the chloride ion percent by weight of cement contributed to concrete at the recommended admixture addition rate.
A number of new admixtures seek to emulate the accelerating properties of calcium chloride without having its corrosive potential. These include formulations based on calcium nitrite, formic acid, calcium formate and the like. Some of these formulations are showing remarkable potential and their use is increasing rapidly. The cost of these chloride-free admixtures is often two, three, or more times that of calcium chloride. Many of them, however, not only act as accelerators but in addition as water-reducers. Though they cost much more than calcium chloride, they seem to offer concrete a long, trouble-free life-span. For the building owner the money-saving request to use calcium chloride as an accelerator may not always save money in the long run.