采用2次注入菌液方式,制备不同浓度营养盐处理的微生物诱导碳酸钙沉淀(MICP)胶结砂样。通过固结排水三轴试验和碳酸钙定量化学试验测定试样强度参数及碳酸钙(CaCO_3)含量,分析了营养盐浓度对胶结砂物理力学特性的影响及碳酸钙沉淀量试...采用2次注入菌液方式,制备不同浓度营养盐处理的微生物诱导碳酸钙沉淀(MICP)胶结砂样。通过固结排水三轴试验和碳酸钙定量化学试验测定试样强度参数及碳酸钙(CaCO_3)含量,分析了营养盐浓度对胶结砂物理力学特性的影响及碳酸钙沉淀量试样强度指标间的关系。结果表明,同等反应时间、同等体积营养盐溶液条件下,随着营养盐浓度的提高试样强度逐渐升高,且达到一定峰值后再下降;碳酸钙晶体分布形态较好条件下,变形模量随着试样干密度的增加而增加;碳酸钙晶体分布形态和沉淀含量共同影响MICP试样强度的提高,试验中0.5 M试样强度提高效果最好,碳酸钙含量、黏聚力、内摩擦角分别为6.03%、46.9 k Pa和41.31°。展开更多
Metallic glasses have aroused considerable interest in the past decades because they exhibit fascinating properties. First, this article briefly outlines the mechanical, thermal properties and application of the metal...Metallic glasses have aroused considerable interest in the past decades because they exhibit fascinating properties. First, this article briefly outlines the mechanical, thermal properties and application of the metallic glasses. In addition, we focus on the dynamic mechanical relaxation behaviors, i.e. main （α） and secondary （β） relaxations, in metallic glasses. The mechanical relaxation behaviors are connected to the mechanical properties and physical properties in glassy materials. The main relaxation in glassy materials is related to the glass transition phenomenon and viscous flow. On the other hand, the β relaxation is linked to many fundamental issues in metallic glasses. In these materials relaxation processes are directly related to the plastic deformation mechanism. The mechanical relaxations, particularly, the β relaxation provides an excellent opportunity to design metallic glasses with desired physical and mechanical properties. We demonstrate the universal characteristics of main relaxation in metallic glasses. The phenomenological models and the physical theories are introduced to describe the main relaxation in metallic glasses. In parallel, we show the dependence of the α. and β relaxations on the thermal treatments in metallic glasses. Finally, we analyze the correlation between the atomic mobility and the thermo-mechanical treatments in metallic glasses. On the one hand, the atomic mobility in metallic glasses is reduced by physical aging or crystallization. On the other hand, the atomic mobility in metallic glass is enhanced by deformation （i.e. compression and cold rolling）. Importantly, to analyze the atomic mobility in amorphous materials, a physical theory is introduced. This model invokes the concept of quasi-point defects, which correspond to the density fluctuations in the glassy materials.展开更多
文摘采用2次注入菌液方式,制备不同浓度营养盐处理的微生物诱导碳酸钙沉淀(MICP)胶结砂样。通过固结排水三轴试验和碳酸钙定量化学试验测定试样强度参数及碳酸钙(CaCO_3)含量,分析了营养盐浓度对胶结砂物理力学特性的影响及碳酸钙沉淀量试样强度指标间的关系。结果表明,同等反应时间、同等体积营养盐溶液条件下,随着营养盐浓度的提高试样强度逐渐升高,且达到一定峰值后再下降;碳酸钙晶体分布形态较好条件下,变形模量随着试样干密度的增加而增加;碳酸钙晶体分布形态和沉淀含量共同影响MICP试样强度的提高,试验中0.5 M试样强度提高效果最好,碳酸钙含量、黏聚力、内摩擦角分别为6.03%、46.9 k Pa和41.31°。
基金the Centre National de la Recherche Scientifique (CNRS) for providing the postdoctoral financial support
文摘Metallic glasses have aroused considerable interest in the past decades because they exhibit fascinating properties. First, this article briefly outlines the mechanical, thermal properties and application of the metallic glasses. In addition, we focus on the dynamic mechanical relaxation behaviors, i.e. main （α） and secondary （β） relaxations, in metallic glasses. The mechanical relaxation behaviors are connected to the mechanical properties and physical properties in glassy materials. The main relaxation in glassy materials is related to the glass transition phenomenon and viscous flow. On the other hand, the β relaxation is linked to many fundamental issues in metallic glasses. In these materials relaxation processes are directly related to the plastic deformation mechanism. The mechanical relaxations, particularly, the β relaxation provides an excellent opportunity to design metallic glasses with desired physical and mechanical properties. We demonstrate the universal characteristics of main relaxation in metallic glasses. The phenomenological models and the physical theories are introduced to describe the main relaxation in metallic glasses. In parallel, we show the dependence of the α. and β relaxations on the thermal treatments in metallic glasses. Finally, we analyze the correlation between the atomic mobility and the thermo-mechanical treatments in metallic glasses. On the one hand, the atomic mobility in metallic glasses is reduced by physical aging or crystallization. On the other hand, the atomic mobility in metallic glass is enhanced by deformation （i.e. compression and cold rolling）. Importantly, to analyze the atomic mobility in amorphous materials, a physical theory is introduced. This model invokes the concept of quasi-point defects, which correspond to the density fluctuations in the glassy materials.
