Comparison between different techniques for monitoring setting and hardening of concrete

Auteurs: Aveline Darquennes, Stéphanie Staquet, Bernard Espion, Olivier Germain et Christian Pierre

Conférence NDTCE’09, Nantes, France ; Juin 2009

Three different techniques to study the evolution of the setting and the hardening of concrete are compared:

(1) ultrasonic monitoring using the FreshCon system,

(2) a resistivity method

(3) the mechanical Kelly-Bryant method.

The experimental tests were carried out on two slag cement concretes in order to compare these methods and to evaluate their ability to monitor continuously the setting and hardening process of concretes with different slag content in the cement. Globally, the initial setting age values given by the three methods were in good agreement, but only the two non-destructive methods (ultrasonic and electric) allow determining the final setting. However, the three methods are complementary and the non-destructive methods give additional information (like chemical reactions, stiffness evolution) about the hydration process of cementitious materials. They are also able to tackle the differences in the setting behaviour due to the slag content in the cement.