Strategies for Prevention of Delayed Ettringite Formation in large Concrete Sections

With many large scale civil engineering construction projects being undertaken, there is a possibility to find large concrete pours in thick members. Due to the hydration process, temperatures in concrete will increase during early stages and when the temperature exceeds 70⁰C, Delayed Ettringite Formation (DEF) can take place. DEF can have adverse long term effects when moisture is present leading to severe cracking of the concrete as it ages. Thus the key to prevent DEF is to control the maximum temperature that concrete could reach during early stages. Mineral additives like fly ash can play a major role in this regard. This paper presents several strategies to mitigate DEF, including the selection of limiting values for member thicknesses that could be cast with different mixes and grades of concrete in different climatic regions in Sri Lanka.

ENGINEER, Vol. 48, No.02, pp. 1-13 2015