| 摘要: |
| 通过三点弯曲施荷，对C30和C50钢筋混凝土构件诱导了宽度为20~88μm不等的微裂缝，然后采用中子透射技术对微裂缝钢混构件中的水分侵入过程进行了可视化成像探测，并对侵入过程中水分的空间分布进行了定量表征.结果表明，即使C30和C50混凝土的微裂缝仅为20μm，也为水分的侵入提供了畅通通道；水分在短时间内即快速充满裂缝，继而在水平方向上沿裂缝两侧、在垂直方向上超越裂缝末端侵入水泥基体；C30混凝土裂缝宽度为82μm(与混凝土保护层厚度比值为039%)时，受拉钢筋与水泥基体界面存在较明显的水分侵入，但其含量较低；水分侵入含量在微裂缝处最高，并以此为中心向裂缝两侧呈对称状逐渐降低. |
| 关键词: 微裂缝 钢筋混凝土 水分渗透 中子成像 定量分布 |
| DOI：103969/j.issn1007 9629201503014 |
| 分类号: |
| 基金项目:国家重点基础研究发展计划（973计划)项目(2015CB655104)；国家自然科学基金资助项目（51420105015，51278260，51208316） |
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| Visualization and Quantification of Water Penetration into Micro cracked Steel Reinforced Concrete |
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ZHANG Peng1, LI Shaochun1, ZHAO Tiejun1, WANG Penggang1, YANG Jinbo2
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1.School of Civil Engineering, Qingdao Technological University, Qingdao 266033, China;2.Beijing Shunyi Commission of Housing and UrbanRural Development, Beijing 101300, China
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| Abstract: |
| Micro cracks with average widths ranging from 20μm to 88μm were induced by three points bending on two types of reinforced concrete C30 and C50. The process of water penetration into these micro cracked concrete were studied experimentally by means of neutron radiography. The spatial water distributions in cracked concrete during water penetration were calculated quantitatively. The results indicate that cracks provide preferential paths for water penetration into cracked concrete even though the crack width is only 20μm. Water penetrated into the fine cracks once contacted the cracked concrete, it will be immediately followed by migrating into the adjacent region from two sides of the cracks horizontally and into the region behind the cracks end vertically. When crack width is up to 82μm, which corresponds to the ratio of 039% between crack width and cover thickness, there is also water ingress existing in the interfaces between steel reinforcement and cement matrix. But the water content in this area is very low. The water profiles have peaks at the positions of cracks, where the profiles start decreasing from both sides of cracks symmetrically. |
| Key words: micro crack steel reinforced concrete water penetration neutron radiography quantitative distribution |
