Abstract: The deterioration of concrete properties from freezethaw actions are studied and the sensibility of various test methods to different deteriorating characteristics is also explored. It is revealed that the flexural strength and splitting tensile strength of concrete deteriorates more rapidly than compressive strength does, which is positively linearly related to mass loss rate and relative dynamic modulus of elasticity. When relative dynamic modulus of elasticity and mass of concrete are reduced respectively by 40% and 5%, the compressive strength is decreased respectively to 19.3% and 25.5% of the initial value. The sensibility of dynamic mechanical velocity to concrete deterioration during freeze-thaw cycles is between that of concrete strength and ultrasonic velocity. The density of hydration products of cement is decreased due to freeze-thaw actions, giving rise to cracks on the bubble wall and increase of porosities with diameter from 25 nm to 75 nm.

Key words: concrete ,    freeze-thaw cycles  ,   deterioration  ,  test  ,  microscopic structure