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Title: Chloride-Free Accelerators for Concrete Setting and Hardening

Author(s): H. Justnes

Publication: Symposium Paper

Volume: 229


Appears on pages(s): 1-18

Keywords: accelerator; chloride-free; hardening; setting; strength

DOI: 10.14359/14725

Date: 9/1/2005

Calcium chloride is an excellent accelerator for concrete, improving both setting time and hardening rate. However, it can not be used for reinforced concrete in efficient dosages because of initiation of rebar corrosion. In the search for other bulk chemicals working as accelerators, calcium nitrate has proven to be a good candidate as set accelerator; however it is not a hardening accelerator (e.g. improving 1 day strength). Efforts have been made to combine calcium nitrate with other admixtures in order to make the mix work as a combined chloride-free setting and hardening accelerator. This paper sums up research over the last 10 years regarding this matter and also compares performance with other chemicals.