| 摘要: |
| 首先采用数值模型得到水泥浆体的模拟微观结构，然后将其离散化为像素.根据该离散化微观结构建立具有扩散性能的格构单元组成的三维格构网络，求解固定离子浓度边界条件下通过水泥浆体的离子流量和内部离子浓度分布，并预测材料的扩散系数.在求解离子浓度分布的过程中，比较了差分法和共轭梯度法的优缺点，发现采用共轭梯度法更快捷.最后用稳态氯离子扩散试验验证了该模拟方法的可靠性，并预测了水泥浆体的氯离子有效扩散系数随水胶比和养护龄期的变化关系. |
| 关键词: 水泥浆体 微观结构 扩散性能 格构模型 |
| DOI：103969/j.issn1007 9629201306019 |
| 分类号: |
| 基金项目:国家自然科学基金资助项目(51308187)；江苏省自然科学基金资助项目(BK20130837)；中国博士后基金资助项目(2013M531266）；江苏省博士后基金资助项目（1202022C）；高性能土木工程材料国家重点实验室开放基金资助项目(2012CEM005) |
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| Simulation of the Steady State Diffusion Behavior Through Cement Paste by 3D Lattice Transport Model |
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LIU Lin1, CHEN Hui su2, SUN Wei2, WU Sheng xing1
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1.College of Civil and Transportation Engineering, Hohai University, Nanjing 210098, China;2.School of Materials Science and Engineering, Southeast University, Nanjing 211189, China
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| Abstract: |
| The transport property is a key factor with regard to the durability and service life of construction materials. It is of importance to establish a computer model to predict the transport properties of cement based materials on the basis of its microstructure coupled with a certain algorithm. First, the virtual microstructure of cement paste was obtained by a numerical model, which was converted to a discrete one represented by voxels. Then a three dimensional(3D) transport network was obtained according to the voxel represented microstructure. The flux through cement paste, the concentration distribution and the diffusion coefficient of cement paste under a given ion concentration boundary condition was calculated. Finite difference method(FDM) and conjugate gradient method(CGM) was compared in solving matrix equations and it was found that CGM is more efficient. Finally, the proposed model is validated by use of experimental data from steady state chloride diffusion test, and is applied to predict the chloride diffusion coefficients of cement paste with different water to cement ratio and at various hydration days. |
| Key words: cement paste microstructure diffusivity lattice transport model |
