Application of ultrasonic methods for early age concrete characterisation

Concrete setting and hardening process are the most critical phases during construction works, influencing to properties of concrete structure, so the application of efficiency nondestructive test methods for early age concrete properties determination is crucial. Penetrometer, pull out and vicat needle methods are standardized methods for young concrete characterisation.. Paper shows that ultrasound methods have potential to be used for these purposes . Ultrasonic waves can propagate through media as transversal, longitudinal and Rayleigh waves. Material properties can be determined based at phase, velocity, frequency, attenuation, relaxation and reflection measurements. With ultrasonic methods, it is possible to determine the kinetics and degree of hydratation, setting time, compressive strength and dynamic modulus of elasticity. Measurements of longitudinal compressive waves velocity through concrete and mortar during hardening process are performed. For mixtures preparation different additives were used. Obtained results indicate possibility for hardening process monitoring and time of cementitius materials setting determination.