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A system dynamics to integrate materials science and structural mechanics

整合材料科学和结构力学的系统动力学

基本信息

批准号：
12450174
负责人：
MAEKAWA Koichi
金额：
$ 9.6万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

(1) In order to predict long-term durability performances of concrete materials, ion migration/dissolution and decomposition of C-S-H gel crystals were modeled in this study. The proposed material model were implemented into DuCOM thermo-hygro system, which covers heat, moisture, chlorides, carbon dioxide, and oxygen transport. In addition, the accelerated experimental results on ion migration and in-situ measurement data were gathered.(2) By reconstructing the thermodynamics theory describing moisture profile in cementitious materials, it has been succeeded to predict continuous hydration process of low water-to-cement ratio concrete.(3) We developed a generalized equilibrium model presenting the relationship between free and bound chiorides for arbitrary powder materials. In case of concrete containing blast furnace slag, the bound component fixed as Freedel's salt is riot significant, but the contribution of adsorbed component brought by dense micro-pore structure is relatively large.(4) A experimental study on shear behavior and tension stiffening of RC beam corroded by ah electric circuit was carried out. It has been cleared that shear capacity depends on the location of corrosion area. We verified that mechanical behavior of corroded structure can be numerically evaluated by the zoning method and the multi directional crack model.(5) Through cyclic loading test for bending and uni-axial members of expansive concrete, we proposed a concept to explain nonlinear behavior of expansive concrete under tensile stress. It was shown that high crack resistance of chemical prestressed member was brought by high deformability before the generation of crack as well as the increase of tensile strength due to prestressing.(6) Based on the revised JSCE code, DuCOM system was modified and customized for Windows environment. This software can predict material properties of concrete by giving mix proportions and environmental conditions.

(1)为了预测混凝土材料的长期耐久性能，本研究模拟了C-S-H凝胶晶体的离子迁移/溶解和分解。将所提出的材料模型应用于DuCOM热湿系统中，该系统涵盖了热量、水分、氯化物、二氧化碳和氧气的传输。此外，收集了离子迁移加速实验结果和现场测量数据。(2)通过对描述胶凝材料水分分布的热力学理论的重构，成功地预测了低水灰比混凝土的连续水化过程。(3)我们开发了一个广义平衡模型，提出了任意粉末材料的自由和结合氯离子之间的关系。对于含高炉渣的混凝土，Freedel盐固定的结合组分贡献不大，而致密微孔结构带来的吸附组分贡献较大。(4)进行了钢筋混凝土梁受电锈蚀后抗剪性能和受拉加固的试验研究。研究表明，混凝土的抗剪承载力取决于腐蚀区的位置。验证了分区法和多向裂纹模型可以对锈蚀结构的力学行为进行数值评估。(5)通过对膨胀混凝土受弯构件和单轴构件的低周反复加载试验，提出了膨胀混凝土在拉应力作用下的非线性行为的概念。结果表明，化学预应力构件的高抗裂性是由裂缝产生前的高变形能力和预应力提高抗拉强度带来的。(6)基于修改后的JSCE代码，对DuCOM系统进行了修改和定制，使其适用于Windows环境。该软件可以通过给定配合比和环境条件来预测混凝土的材料性能。