Monitoring and modelling the early age and hardening behaviour of eco-concrete through continuous non-destructive measurements: Part II. Mechanical behaviour

A recent scientific and industrial interest has been brought to combine multiple supplementary cementitious materials (SCM) in large quantities in concrete binders. The growing use of binary, ternary or quaternary cement binders calls for the development of simple, efficient and accurate experimental and numerical means to characterise and predict the behaviour of such concretes. Continuous non-destructive testing constitutes a major opportunity since it generally consists in simple test setup requiring low human interaction. In this study, isothermal calorimetry and ultrasonic pulse velocity (compression and shear waves) are performed on various concrete compositions with massive incorporation of limestone filler and blast-furnace slag. Indeed, these two additions present interesting complementary effects and positive synergies in terms of fresh properties, mechanical behaviour and durability potential. The setting time, compressive and tensile strength and elastic modulus of these concretes is investigated from the setting time to the hardened state. The existing models linking these properties to the hydration degree, ultrasonic pulse velocity or hydration time are not applicable to these materials, especially during the early age period. New models are proposed and validated for the early age behaviour of concrete with SCMbased binders.