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硅酸盐通报 ›› 2026, Vol. 45 ›› Issue (4): 1282-1295.DOI: 10.16552/j.cnki.issn1001-1625.2025.0945

• 资源综合利用 • 上一篇    下一篇

Mg2+-SO42--Cl-侵蚀粉煤灰-偏高岭土复掺再生混凝土离子传输与物相组成演化研究

刘东明1(), 杨关飞1, 朱辉国1, 王家滨2(), 韩会阳2   

  1. 1.中交二公局第四工程有限公司,洛阳 471013
    2.西安工业大学建筑工程学院,西安 710021
  • 收稿日期:2025-09-22 修订日期:2025-10-27 出版日期:2026-04-20 发布日期:2026-05-14
  • 通信作者: 王家滨,博士,副教授。E-mail:wangjiabin@xatu.edu.cn
  • 作者简介:刘东明(1990—),男,高级工程师。主要从事建筑固废资源化的研究。E-mail:427779303@qq.com
  • 基金资助:
    国家自然科学基金(51908440);陕西省自然科学基金(2024JC-YBMS-268)

Ion Transport and Mineral Phases Composition Evolution in Recycled Aggregate Concrete with Fly Ash-Metakaolin Exposed to Mg2+-SO42--Cl- Solution

LIU Dongming1(), YANG Guanfei1, ZHU Huiguo1, WANG Jiabin2(), HAN Huiyang2   

  1. 1.CCCC-SHEC Fourth Engineering Co. ,Ltd. ,Luoyang 471013,China
    2.School of Civil & Architecture Engineering,Xi’an Technological University,Xi’an 710021,China
  • Received:2025-09-22 Revised:2025-10-27 Published:2026-04-20 Online:2026-05-14

摘要:

我国西部地区盐渍土广泛分布,其中腐蚀性Mg2+SO42?-、Cl-对再生混凝土(RAC)结构耐久性产生了极大的危害。试验采用7.5%MgSO4-7.5%Na2SO4-5.0%NaCl(质量分数)溶液模拟西部盐渍土中的主要腐蚀介质,开展RAC盐腐蚀试验。采用固液萃取法、电位法和化学滴定法,分别测试了RAC中水溶性Mg2+SO42?-、Cl-、Ca2+的含量和pH值,探究偏高岭土取代率对RAC中离子含量与传输过程的影响。测试并分析盐腐蚀RAC的物相组成,揭示物相组成的演化规律与影响机制。腐蚀离子含量均随着RAC中偏高岭土的取代率增大逐渐提高,Ca2+含量和pH值则持续降低。侵蚀时间相同时,Cl-在RAC中的传输范围最大,Mg2+的传输范围最小,Ca2+和pH值的变化受Mg2+SO42?-扩散的影响显著。偏高岭土取代率增大,RAC中不溶性腐蚀产物的物相组成快速减少,可溶性腐蚀产物物相组成增多;随着侵蚀时间与暴露深度的增加,腐蚀产物物相组成先由简单向复杂转变后再逐渐简单化。侵蚀时间短或暴露深度大的RAC中,腐蚀产物物相组成简单或仅存在水化产物物相。

关键词: 再生混凝土, 盐渍土环境, Mg2+-SO42?--Cl-侵蚀, 偏高岭土取代率, 离子传输, 物相组成

Abstract:

Saline soils widely distributed in western China contain aggressive ions of magnesium, sulfate and chloride, severely threatening the durability of recycled aggregate concrete (RAC) structures. A solution simulating the primary aggressive media of these soils—comprising 7.5% MgSO4, 7.5% Na2SO4, and 5.0% NaCl (mass fraction)— was utilized for RAC salt attack experiments. Water-soluble contents of magnesium, sulfate, chloride, and calcium, and pH values were measured by solid-liquid extraction, potentiometry, and chemical titration methods to investigate the effect of metakaolin replacement ratio on ion content and transport behavior. Analysis of mineral composition of exposed RAC elucidates evolutionary patterns and influencing mechanisms. Results indicate that aggressive ion contents increase gradually with higher metakaolin replacement ratios, whereas calcium content and pH values decrease continuously. At equivalent exposure times, chloride exhibites the widest migration range within RAC, compared to the most restricte migration shown by magnesium. Changes in calcium concentration and pH are significantly influenced by magnesium and sulfate diffusion. Higher metakaolin replacement ratios result in a rapid decrease in the mineral composition of insoluble corrosion products and an increase in that of soluble corrosion products. Prolonged exposure times and greater exposure depths cause the mineral composition of corrosion products to transform from simple to complex, followed by progressive simplification. Simplified mineral compositon of corrosion products, or those consisting solely of hydration product phases, is observed in RAC subjected to either short-term exposure time or deeper exposure depths.

Key words: recycled aggregate concrete, saline soil envoronment, Mg2+-SO42?--Cl- erosion, replacement ratio of metakaolin, ions transport, mineral composition

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