膨润土与水泥掺比对塑性混凝土变形特性的影响

Impacts of bentonite and cement mixing ratio on deformation characteristics of plastic concrete

通过4组不同膨润土与水泥掺比(0.93,0.50,0.35,0.26)的塑性混凝土常规三轴压缩试验,研究了膨润土与水泥掺比对塑性混凝土变形特性(割线模量、峰值应变、体积变形、模强比)的影响规律。试验结果表明,随着膨润土与水泥掺比的降低,塑性混凝土峰值应变和最大体积压缩量均显著降低,即材料抗裂性和变形性能显著降低。膨润土与水泥掺比对模强比的影响规律不一致,膨润土与水泥掺比为0.93或0.50时,塑性混凝土模强比有随围压增加而先增后降的趋势;膨润土与水泥掺比为0.35或0.26时,塑性混凝土模强比表现为随围压增加而逐渐降低的趋势。最后,根据三轴试验结果整理分析了符合Duncan-Chang本构模型的塑性混凝土本构参数。

By use of conventional triaxial compression tests, changing trends of the secant modulus, volumedeformation, peak strain and the ratio of modulus to strength of the plastic concrete are obtained from changedbentonite and cement mixing ratios （ 0. 93, 0. 50, 0. 35, 0. 26）. The analysis results show that the peak strain andthe maximum volume compression drop significantly with the decrease of the bentomite and cement mixing ratio,namely the crack resistance and ductility of the material are significantly decreased. The impacts of the bentoniteand cement mixing ratios on the ratio of modulus to strength are not very remarkable. When the bentonite andcement ratios of the plastic concrete are 0. 93 or 0. 50, the ratios of modulus to strength are first increased and thendecreased with increase of the confining pressure. But when the betonite and cement ratios are 0. 35 or 0. 26, theratios of modulus to strength decrease gradually with increase of the confining pressure. Finally, according to theresearch results of the triaxial tests, the analysis of parameters of the constitutive model for the plastic concreteconforming with the Duncan-Chang constitutive model has been made in the testing.