Chloride permeability of recycled aggregate concrete under the coupling effect of freezing-thawing, elevated temperature or mechanical damage
Chloride permeability of recycled aggregate concrete under the coupling effect of freezing-thawing, elevated temperature or mechanical damage
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冻融、高温或机械损伤耦合作用下再生骨料混凝土氯离子渗透率
DOI：
10.1016/j.conbuildmat.2019.117648
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发表时间：
2020-03-20
影响因子：
7.4
通讯作者：
Duan, Zhenhua
中科院分区：
文献类型：
--
作者：
Ma, Zhiming;Liu, Miao;Duan, Zhenhua
氯离子渗透常常导致钢筋锈蚀，降低钢筋混凝土的耐久性。尽管已有研究对再生骨料混凝土(RAC)的氯离子渗透性进行了研究，但很少有人考虑预损伤的RAC的氯离子渗透性。考虑到RAC可能会受到各种暴露环境的影响，本文重点研究了RAC在冻融、高温或机械损伤等耦合作用下的氯离子渗透性。首先通过冻融、高温或外加载荷试验对RAC进行初始损伤，然后对不同预损伤的RAC进行氯离子扩散试验。结果表明，再生粗集料(RCA)掺量越大，RAC的氯离子渗透率越高。在恶劣环境下，RCA的掺入增加了RAC的冻融、高温或机械损伤。氯离子渗透率随初始损伤的增加而增大，且两者之间存在良好的关系。RCA的掺入提高了RAC在恶劣环境下对氯离子渗透性的敏感性，如掺入100%RCA的RAC的氯离子扩散系数比未破坏的素混凝土高51.4%，而冻融循环75次和f(C)80%后的氯离子扩散系数分别为233.3%和62.1%。(C)2019爱思唯尔有限公司。保留所有权利。
Chloride penetration frequently leads to a steel corrosion and reduces the durability of reinforced concrete. Although the previous studies have investigated the chloride permeability of recycled aggregates concrete (RAC), the chloride permeability of RAC with pre-damage received little considerations. Considering that the RAC may be subjected to various exposure environments, this paper focused on exploring the chloride permeability of RAC under the coupling effect of freezing-thawing, elevated temperature or mechanical damage. The freezing-thawing, elevated temperature or applied loading test was first employed to induce initial damage on RAC, and then the chloride diffusivity test was conducted on RAC with various pre-damages. The findings showed that the chloride permeability of RAC increased with increasing recycled coarse aggregate (RCA) content. Exposing to harsh environment, the incorporation of RCA increased the freezing-thawing, elevated temperature or mechanical damage of RAC. The chloride permeability increased with increased initial damage, and a good relation could be observed between them. The incorporation of RCA improved the sensitivity to the chloride permeability of RAC exposed to harsh environment; such as, the chloride diffusion coefficient of RAC with 100% RCA was 51.4% higher than that of the plain concrete without pre-damage, while the results were 233.3% and 62.1% after 75 freezing-thawing cycles and 80% f(c). (C) 2019 Elsevier Ltd. All rights reserved.