水压力环境中混凝土的含水量及其对力学性能的影响

为研究有压水环境中混凝土的含水量特征及孔隙水对混凝土力学性能的影响,通过试验获得了混凝土在水压力下的含水量曲线,并基于细观管道孔隙网格模型探讨了水压力变化对含水量和孔隙水分布的影响,进一步分析了混凝土含水量和孔隙水尺度对其静动态力学性能的作用机理。结果表明:混凝土含水量随水压力提高而增加,但水压力超过一定值后,含水量的增幅不显著;在高水压力下混凝土的孔隙水流动空间减少,且部分孔隙水具有更小的尺度,在动态荷载作用下孔隙水将产生显著的黏滞应力和超孔隙水压力,导致混凝土强度随应变速率提高呈非线性增长,但水压力对强度的影响不显著。简言之,水压力环境中混凝土的力学性能不仅与含水量和加载速率有关,还与孔隙水的尺度密切相关。

Water content in concrete under water pressure environment and the effect on its mechanical properties

This paper presents a study on the water content characteristic and the influence of pore water on mechanical properties when concrete under water pressure environment. The test was carried out to obtain curves of water content for concrete under different water pressure, and influence of water pressure variation on water content and distribution of pore water was discussed based on the mesoscopical pipe-pore network model. Furthermore, mechanism for effect of water content and scale of pore water on the static and dynamic mechanical properties of concrete was analyzed. The results show that water content of concrete increases with increasing water pressure, while water pressure exceeds a certain value, the increase of water content is insignificant; under high water pressure, the pore space in concrete is less for water to flow and a portion of pore water is on smaller scale,which resulting in greater viscous stress and excess pore water pressure when concrete under the dynamic loading, and these can lead to the nonlinear increase for the strength of concrete as strain rate rises. However, the strength of concrete is not affected by water pressure. In conclusion,the mechanical properties of concrete are not only related with water content and loading rate,and but also closely related to the scale of pore water.