Experimental study of the influence of the temperature and duration of heat treatments at early age on the risk of concrete expansion associated with Delayed Ettringite Formation

Delayed Ettringite formation (DEF) is an autogenous expansive reaction that can affect concrete. A long enough exposure to high enough temperature are the necessary conditions to develop DEF. The results of experimental laboratory investigations that aim to quantify the effect of thermal history on DEF characteristics (namely magnitude and kinetics of expansion) are presented. A threshold of temperature for the concrete at early age, a pessimum effect with the heating duration and a relation between thermal energy and swelling parameters (kinetics and magnitude) are highlighted.