黏性对动力荷载下混凝土强度的影响机理

Influence mechanism of pore liquid viscosity on concrete strength under dynamic loading

本文研究了黏性对动力荷载下混凝土强度的影响机理。开展了水饱和、干燥和填充不同黏性液体以及高温烘烤后的混凝土动力性能试验,分别采用强度增加值和动力增强系数分析了填充液体黏度对动载下混凝土强度的影响规律,并采用多元回归分析了黏性和加载速率对动力荷载下混凝土强度影响大小。在统计分析现有动力试验数据的基础上,分析了不同试验条件下混凝土内部水分迁移规律,研究了材料内部孔隙水和毛细水对混凝土动力性能的影响机理。研究表明,在地震荷载加载速率范围内采用绝对值描述动力荷载下混凝土强度增加更合理,黏性对动载下混凝土强度的影响主要通过材料内部毛细水产生作用,常规干燥和饱和混凝土在动力荷载下的强度增加值并无差别。

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.