Abstract: This paper discusses the influence mechanism of pore liquid viscosity on concrete strength under dynamic loading. We conduct an experimental study on the dynamic behaviors of concrete materials under different conditions: dry, water-saturated, filled with liquids of different viscosity, and high-temperature baking. Influence of filling liquid viscosity on concrete strength under dynamic loading is analyzed using its strength increase and dynamic increase factor separately; multiple regression analysis is used to examine the impacts of pore liquid viscosity and loading rate on concrete strength under dynamic loading. On the basis of statistical analysis on the test data from previous studies and of our own, we analyze internal water migration in concrete, and discuss the influence mechanism of pore water and capillary water on the dynamic properties of concrete. We show that under seismic loading, it is more reasonable to use absolute values to describe concrete strength increase corresponding to the range of strain rates. And, no considerable difference in strength increase has been observed between dry and saturated concretes, and the effect of viscosity on concrete strength is mainly from capillary water inside the material.

Key words: viscosity, dynamic loading, strength, free water, concrete