Trade Journals for the Concrete Industry

The use of concrete admixtures increases the possibilities to produce concrete with special properties as well as under harsh conditions. Over the years many inorganic and organic admixtures have been investigated and brought to market. After more than 20 years of application Calcium Nitrate turns out to be a very versatile concrete admixture. Initially, Calcium Nitrate has been used as a chloride free set accelerator. And soon it became popular as cold weather concrete admixture – “Anti-freeze”. The setting acceleration has been used, too, for the compensation of retardation by water reducers (Plasticisers). And over the years it was observed that the use of Calcium Nitrate leads in most cases to a moderate enhancement of the long term compressive strength. And last but not least the corrosion inhibitor effect for embedded reinforcement steel against chloride induced corrosion has been found. The setting acceleration may be achieved by small dosages (in the range 0.2% - 1.0% dry admixture by mass of cement). The interaction with polymers but also strength enhancement demands moderate dosages (1% - 3%). The corrosion inhibition requires high dosages (3% and above).