深圳大学学报理工版

有害离子通过水为媒介在水泥基材料内部传输,引起钢筋混凝土的劣化发展,缩短了混凝土结构的服役年限. 为研究水泥基材料因水分传输引起的劣化机理,基于X射线断层扫描技术,采用碘化钠溶液作为图像增强剂,对水分在水泥净浆内部的传输过程进行原位和无损可视化追踪,分析水在水泥基体的吸水渗透深度变化. 研究表明,当采用质量分数为10%的碘化钠溶液时,X射线断层扫描技术可清晰表征水分在净浆中的二维和三维传输过程; 通过X射线断层扫描技术测定的吸水深度与时间平方根呈线性关系,符合Locas-Washburn方程.

Harmful ions transport inside the concrete by the medium of water, causing the deterioration of concrete and the steel-bar corrosion development and shortening the service life of concrete. In order to study the degradation mechanism of cement-based material due to water transportation, this study in-situ traces the water transport process in cement paste non-destructively and quantitatively analyzes the relationship between water uptake depth and absorption time by means of X-ray computed tomography microscope(X-ray μCT)combined with NaI enhancing. The results show that the 2D and 3D evolution of water transport in cement paste could be clearly characterized by X-ray μCT method with mass fraction of 10% NaI solution. What's more, the absorption depth measured by X-ray μCT is linear with the square root of time, which is consistent with Locas-Washburn equation.

引言
1 实验
2 结果与讨论
3 结论

图1 试验样品示意图<br/>Fig.1 Schematic presentation of test specimen

图1 试验样品示意图
Fig.1 Schematic presentation of test specimen

表1 水泥成分质量分数<br/>Table 1 Components and mineral composition of portland cement%

表1 水泥成分质量分数
Table 1 Components and mineral composition of portland cement%

图2 毛细吸水试验的示意图<br/>Fig.2 Schematic presentation of water uptake test

图2 毛细吸水试验的示意图
Fig.2 Schematic presentation of water uptake test

图3 X-ray μCT系统成像工作原理图<br/>Fig.3 Schematic illustration of X-ray μCT system

图3 X-ray μCT系统成像工作原理图
Fig.3 Schematic illustration of X-ray μCT system

图4 水泥净浆试样吸水30 min后的重构形态图 <br/>Fig.4 The reconstructed morphology images of water uptake in cement sample for the first 30 min

图4 水泥净浆试样吸水30 min后的重构形态图
Fig.4 The reconstructed morphology images of water uptake in cement sample for the first 30 min

图5 不同时间试样中毛细吸水深度变化2D图<br/>Fig.5 The 2D evolution of water uptake at different times in the center of the cement sample

图5 不同时间试样中毛细吸水深度变化2D图
Fig.5 The 2D evolution of water uptake at different times in the center of the cement sample

图6 不同时间试样中毛细吸水深度变化3D图<br/>Fig.6 The 3D evolution of water transport at different times in cement paste

图6 不同时间试样中毛细吸水深度变化3D图
Fig.6 The 3D evolution of water transport at different times in cement paste

图7 不同时间沿中轴线切开的试样图<br/>Fig.7 The testing specimens along cut-off axis at different times

图7 不同时间沿中轴线切开的试样图
Fig.7 The testing specimens along cut-off axis at different times

表2 不同吸水时间净浆试样沿中轴线切开的深度测量值<br/>Table 2 The measured depth along cut-off axis of the testing specimens at different times

表2 不同吸水时间净浆试样沿中轴线切开的深度测量值
Table 2 The measured depth along cut-off axis of the testing specimens at different times

图8 水分上升高度与吸水时间平方根的关系<br/>Fig.8 Height of water front versus the square root of exposed time

图8 水分上升高度与吸水时间平方根的关系
Fig.8 Height of water front versus the square root of exposed time

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备注

引言

1 实验

2 结果与讨论

3 结论

期刊信息

备注

引言

1 实 验

2 结果与讨论

3 结 论

期刊信息

1 实验

3 结论