Degradation of submerged/wet concrete under cyclic compression and cyclic shear
Degradation of submerged/wet concrete under cyclic compression and cyclic shear
复制标题
循环压缩和循环剪切下水下/湿混凝土的降解
DOI：
10.1051/matecconf/201925805012
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发表时间：
2019
影响因子：
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通讯作者：
藤山 知加子・ 子田 康弘・ 仙頭 紀明
中科院分区：
文献类型：
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作者：
Yanyan Liu;Akira Igarashi;宮崎泰樹，貝沼重信;藤山 知加子・ 子田 康弘・ 仙頭 紀明
本研究的目的是确定在钢筋混凝土 (RC) 桥面板中观察到的具体混凝土退化情况。为了控制这种现象，进行了基础研究。对具有不同预载和约束条件的水下混凝土圆柱体试件循环施加压缩载荷和外部水压。装载过程中普遍观察到罐内水的浑浊度，且随着循环次数的增加，浑水的pH值稳步上升。此后，在分裂样本的内表面上发现了没有水泥基体的细骨料。对这些现象进行了定量分析，分析表明循环水压作用于预裂试件内部并冲刷了其水泥基体。还使用循环剪切试验检查了粗糙裂纹表面的退化情况，有/没有向裂纹供水。当存在供水时，剪切滑移和正交位移随着循环次数的增加而明显放大。结合液化的力学性能讨论了水剪切开裂混凝土的力学性能。这些基础研究可以帮助确定降解的加速因素，并为实际使用提供一定的阈值。
The aim of this study is to identify a specific degradation of concrete that has been observed in bridge decks made of reinforced concrete (RC). To control the phenomenon, fundamental studies were conducted. Compressive loads and external water pressure were cyclically applied to submerged concrete cylinder specimens with different pre-loading and restraint conditions. The turbidity of the water in the tank was generally observed during the loading, and the pH of the turbid water steadily increased as the number of cycles increased. Thereafter, fine aggregates without a cement matrix were found on the inner surfaces of split specimens. These phenomena were quantitatively analyzed, and the analyses suggested that cyclic water pressure acted on the inside of pre-cracked specimens and washed out their cement matrix. The degradation of a rough cracked surface was also examined using the cyclic shear test, with/without a water supply to the crack. The shear slip and the orthogonal displacement were clearly amplified with an increase in the number of cycles when the water supply was present. The mechanical properties of cracked concrete with water in shear was discussed in accordance with that of liquefaction. These fundamental studies could help to determine the acceleration factors of the degradation and provide certain thresholds for practical use.