不同加载速率下干燥与饱和混凝土抗压性能试验研究分析

在准静态及中低加载速率下,开展了饱和与干燥混凝土力学性能变化的试验研究。与干燥的混凝土相比,饱和混凝土的峰值应变减小,弹性模量增大,饱和混凝土的强度对加载速率较为敏感:准静态加载条件下饱和混凝土的强度有所降低,随着加载速率提高饱和混凝土强度增加的较多。本文针对试验现象进行了机理分析,将饱和混凝土的力学性能的变化归结为混凝土孔隙和裂纹中的自由水对混凝土基体有着不同的作用形式;根据应力应变曲线的特点,探讨了饱和与干燥混凝土的统一应力应变全曲线方程;建立了不同加载速率下饱和与干燥混凝土的强度率相关模型,通过与试验数据的对比,本文模型可以较好地反映两种状态混凝土力学性能的变化趋势,

Experiments of the compressive properties of dry and saturated concrete under different loading rates

The compressive properties of saturated and dry concretes including strength,elastic modulus and peak strain under different loading rates are studied by experiments.Compared with the dry concrete,the peak strain of saturated concrete decreases and the elastic modulus of saturated concrete increases much more.The strengths of saturated concrete are more sensitvie to the loading rate than dry concrete;the compressive strength of saturated concrete decreases under the quasi-static loading rate but increases under high loading rate.The mechanism of these changes is carried out based on the different acting models of free water in cracks under different loading rates.The uniform numerical stress-strain relationship is putted forward due to the good similarity on the stress-strain curve of saturated and dry concrete.The relationships between strength and loading rates of saturated and dry concrete are modeled on the different effects of free water in the concrete.Numerical models are in good agreements with the experimental data and feasible to be applied in compatation and further investigation.