Influence of surface carbonation on the electrochemical chloride extraction of recycled aggregate concrete and sensitivity analysis

IF 10.8 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement & concrete composites Pub Date : 2025-03-15 DOI:10.1016/j.cemconcomp.2025.106041

Feng Qu , Yuhao He , Congtao Sun , Lin Chen , Gang Peng , Gongxun Wang , Hailong Hou

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引用次数: 0

Abstract

At present, applying ECE technology to existing concrete structures to enhance durability and service life is feasible. However, the combined effects of chloride salts and carbonation in marine environments introduce complex influence mechanisms on concrete structures treated with ECE, especially for reinforced concrete projects incorporating RCA. This paper studies the effect of different factors on the ECE of carbonated RAC. The effects include RCA quality and replacement rate, FA admixture, electrochemical parameters, etc. The results indicate that optimal dechlorination efficiency is observed at FA content of 10 %. Overall, increased replacement of RCA improves the dechlorination efficiency with a 26.19 % increase recorded at 100 % replacement ratio compared to NAC. After carbonation, the decomposition of hydration products such as C-S-H reduced the mechanical properties of concrete, but the extended carbonation duration enhanced the ECE effectiveness. With the extension of carbonation time to 28d, the dechlorination efficiency increases by 14.27 %. Longer times and higher energizing currents can enhance for ECE. Dechlorination efficiency of carbonated RAC increased by 42.8 % after 28d of chloride extraction, compared to 7d.Sensitivity analysis highlighted that the electrochemical parameters had the most significant effect on ECE effectiveness. The sensitivity of current density to dechlorination efficiency and the sensitivity of chloride extraction time to the [Cl⁻]/[OH⁻] are 0.241 and 5.418, respectively. This will contribute to improving the durability of RAC structures in marine environments and advancing low-carbon engineering.

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表面碳化对再生骨料混凝土电化学提取氯化物的影响及敏感性分析

目前，将ECE技术应用于既有混凝土结构，提高耐久性和使用寿命是可行的。然而，海洋环境中氯化物盐和碳酸化的综合作用对经ECE处理的混凝土结构，特别是对采用RCA的钢筋混凝土项目，产生了复杂的影响机制。研究了不同因素对碳酸化RAC ECE的影响。影响因素包括RCA质量和替换率、FA掺量、电化学参数等。结果表明，FA含量为10%时脱氯效果最佳。总体而言，与NAC相比，RCA替代率的增加提高了脱氯效率，在100%替代率下，脱氯效率提高了26.19%。碳化后，C-S-H等水化产物的分解降低了混凝土的力学性能，但碳化时间的延长提高了混凝土的ECE效果。随着碳化时间延长至28d，脱氯效率提高14.27%。更长的时间和更高的激励电流可以增强ECE。经过28d的氯萃取后，活性炭的脱氯效率比7d提高了42.8%。敏感性分析显示，电化学参数对ECE效果的影响最为显著。电流密度对脱氯效率的敏感性为0.241，氯离子萃取时间对[Cl-]/[OH-]的敏感性为5.418。这将有助于提高RAC结构在海洋环境中的耐久性和推进低碳工程。

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来源期刊

Cement & concrete composites 工程技术-材料科学：复合

CiteScore

18.70

自引率

11.40%

发文量

459

审稿时长

65 days

期刊介绍： Cement & concrete composites focuses on advancements in cement-concrete composite technology and the production, use, and performance of cement-based construction materials. It covers a wide range of materials, including fiber-reinforced composites, polymer composites, ferrocement, and those incorporating special aggregates or waste materials. Major themes include microstructure, material properties, testing, durability, mechanics, modeling, design, fabrication, and practical applications. The journal welcomes papers on structural behavior, field studies, repair and maintenance, serviceability, and sustainability. It aims to enhance understanding, provide a platform for unconventional materials, promote low-cost energy-saving materials, and bridge the gap between materials science, engineering, and construction. Special issues on emerging topics are also published to encourage collaboration between materials scientists, engineers, designers, and fabricators.