Application of synchrotron microtomography for pore structure characterization of deteriorated cementitious materials due to leaching
Application of synchrotron microtomography for pore structure characterization of deteriorated cementitious materials due to leaching
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DOI：
10.1016/j.cemconres.2009.10.009
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发表时间：
2010-08-01
影响因子：
11.4
通讯作者：
Takeda, N.
中科院分区：
文献类型：
--
作者：
Sugiyama, T.;Promentilla, M. A. B.;Takeda, N.
采用电化学迁移技术进行加速浸出试验，制备了劣化砂浆和水泥净浆(w/c=0.50)。该技术使CaO/SiO(2)摩尔比降至2.0以下。使用同步辐射X射线计算机显微断层扫描技术，对硬化水泥浆体和砂浆中劣化水泥基质的内部微结构进行了无损三维成像。日本。在0.5微米/体素的空间分辨率下进行图像分析后，显微层析图像成功地显示了退化水泥基质中增加的孔隙空间，有效孔隙率在0.31~0.38之间。此外，随机游走模拟得到的孔隙空间扩散曲折度也作为孔隙结构输运参数进行了评估。有迹象表明，由于孔洞连通性在亚微米尺度上变大，主要由孔洞溶解引起的水泥基质的劣化使扩散曲折度减小到个位数。(C)2009爱思唯尔有限公司。保留所有权利。
Deteriorated mortars and cement pastes (w/c = 0.50) were prepared by an accelerated leaching test using electrochemical migration technique. This technique enabled the reduction of the CaO/SiO(2) molar ratio to less than 2.0. Non-destructive three-dimensional imaging of the internal microstructure of the deteriorated cement matrix in hardened cement paste and mortar was performed using synchrotron X-ray computed microtomography at SPring-8. Japan. After image analysis at a spatial resolution of 0.5 mu m/voxel the microtomographic images successfully visualized increased pore spaces in the deteriorated cement matrix with the effective porosity ranging from 0.31 to 0.38. In addition the diffusion tortuosity in the pore space derived from random walk simulation was also evaluated as a pore structure-transport parameter. Indications suggest that the deterioration of the cement matrix due primarily to the dissolution of portlandite decreases the diffusion tortuosity to a single digit as the degree of pore connectivity becomes larger at the submicron scale. (C) 2009 Elsevier Ltd. All rights reserved.