Determination of elastic properties of high-performance concrete at early ages
Résumé
Knowledge of the elastic properties of concrete at early ages is very useful for designers, especially from a serviceability point of view. This paper discusses the determination at early ages of the elastic properties of three different concretes with water-cementitious materials ratios of 0.45, 0.35, and 0.30. Static and dynamic tests on the modulus of elasticity were carried out to monitor the evolution of this important parameter from 8 h of age and thereafter. A correlation factor between the static and dynamic moduli of concretes with a water/binder ratio between 0.30 and 0.45 is proposed. The relationship predicting the static modulus of elasticity of concrete was found to be proportional to the square root of the concrete compressive strength. The Poisson's ratio was found to decrease sharply in very little time to reach a 0.14 value at a very young age, and then increased to approximately 0.24 after 7 days.