硅酸盐学报

钢管约束混凝土中硫酸根离子传输特征与扩散模型

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曹杰荣 ¹^,² , 金鸣 ¹^,² , 丁庆军 ³ , 赵海涛 ⁴ , 庄智杰 ⁵ , 刘加平 ¹^,²

硅酸盐学报 | 混凝土耐久性机理表征与预测方法专题—研究论文 2026,54(2): 611-622

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硅酸盐学报 |混凝土耐久性机理表征与预测方法专题—研究论文 2026 , 54 (2) : 611 -622

钢管约束混凝土中硫酸根离子传输特征与扩散模型

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曹杰荣¹^,², 金鸣¹^,², 丁庆军³, 赵海涛⁴, 庄智杰⁵, 刘加平¹^,²

作者信息

^1．东南大学材料科学与工程学院，南京 211189

^2．东南大学，重大基础设施工程材料全国重点实验室，南京 211103

^3．武汉理工大学材料科学与工程学院，武汉 430070

^4．河海大学土木与交通学院，南京 210024

^5．江苏苏博特新材料股份有限公司，南京 211103

通讯作者:

刘加平（1967—），男，博士，教授。

作者简介:

曹杰荣（1991—），男，博士，助理研究员。

Transport Characteristics and Diffusion Model of Sulfate Ions in Steel Tube Confined Concrete

Jierong CAO¹^,², Ming JIN¹^,², Qingjun DING³, Haitao ZHAO⁴, Zhijie ZHUANG⁵, Jiaping LIU¹^,²

Affiliations

^1.School of Materials Science and Engineering, Southeast University, Nanjing 211189, China

^2.National Key Laboratory of Major Engineering Materials for Major Infrastructure, Nanjing 211103, China

^3.School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China

^4.College of Civil and Transportation Engineering, Hohai University, Nanjing 210024, China

^5.Jiangsu SuBOT New Materials Co., Ltd., Nanjing 211103, China

Corresponding Author:

LIU Jiaping (1967-), male, Ph.D., Professor. E-mail: liujiaping@cnjsjk.cn

CAO Jierong (1991-), male, Ph.D., Assistant Researcher. E-mail: jierongcao@126.com

出版时间: 2026-02-20 doi: 10.14062/j.issn.0454-5648.20250602

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摘要

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硫酸盐侵蚀会引发混凝土膨胀开裂，进而加速硫酸根离子向内部迁移，最终导致混凝土性能快速劣化。外围钢管能通过其套箍效应有效抑制混凝土的开裂，能够提升混凝土抗硫酸盐侵蚀性能。为探明钢管约束下混凝土中硫酸根离子传输行为，本研究选用普通硅酸盐水泥（高C₃A含量）与抗硫酸盐水泥（低C₃A含量），开展了不同壁厚钢管约束下混凝土抗硫酸盐侵蚀试验；通过径向膨胀、约束应力、离子传输及孔结分布，系统研究了钢管约束条件下混凝土中硫酸根离子的传输特征与机制。研究结果表明：相比无约束混凝土，钢管套箍效应有效抑制了硫酸盐侵蚀诱发的混凝土膨胀开裂，密实了混凝土基体，并显著降低了硫酸根离子的扩散系数与浓度。钢管提供的约束应力均随水泥中C₃A含量、硫酸盐浓度及钢管壁厚的增加而提高。所建立的钢管约束下基于混凝土时变孔隙率的硫酸根离子扩散模型与试验数据吻合良好。

关键词

硫酸盐侵蚀 / 钢管约束 / 硫酸根离子传输 / 传输模型

Abstract

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Introduction

In the saline soil environments of the western China, bridge piers often experience "root rotting" in the adsorption zone about 50 cm above the ground/water surface due to dual sulfate erosion. This phenomenon manifests as severe spalling and cracking, significantly shortening the service life of the bridges. It is thus urgent to take effective measures in the section to retard sulfate transport under capillary action and enhance the durability of concrete. Physical coating layers such as epoxy resin can effectively block sulfate ingress into the piers, but a long-term exposure to ultraviolet radiation and high temperatures can lead to aging and failure. Although fiber-reinforced composites can isolate erosion and restrain concrete, they exhibit a poor high-temperature resistance and may release toxic gases in case of fire. In contrast, steel tube-confined concrete improves load-bearing and seismic capacity and effectively inhibits expansion cracking of concrete caused by sulfate erosion. This study was to investigate the influence patterns and mechanisms of sulfate ion transport in steel tube-confined concrete. The effect of steel tube confinement on the sulfate ion transport behavior in concrete was investigated at different steel tube wall thicknesses, C₃A contents, and sulfate concentrations. In addition, a corresponding sulfate ion transport model was also established.

Methods

Specimens were cast using cylindrical molds made of PVC and steel tubes with the dimensions of φ100 mm×50 mm. After 24 h demolding, the specimens were standard-cured for 28 d. After curing, the specimens in PVC molds were removed, and their sides were sealed with epoxy resin to serve as unconfined specimens, ensuring one-dimensional sulfate ion transport.

All the specimens were immersed in a Na₂SO₄ solution (replaced every two weeks), and radial expansion and ion content were measured at specified ages. The radial expansion of confined and unconfined concrete specimens was determined by a ±0.001 mm electronic micrometer (Sanliang Co., Japan). The total sulfate ion concentration in the concrete was characterized by an inductively coupled plasma atomic emission spectrometer (ICP-AES). The pore structure of sulfate-eroded concrete was determined by a low-field nuclear magnetic resonance (LF-NMR) technology (Suzhou Niumag Analytical Instrument Co., Ltd., China)

Results and Discussion

Compared with unconfined concrete, steel tube confinement reduces the sulfate ion content and diffusion coefficient in concrete. Increasing the C₃A content, sulfate concentration, and steel tube wall thickness further decreases the sulfate ion content and diffusion coefficient in steel tube-confined concrete. This is because sulfate erosion causes a concrete expansion, and the confinement effect of the steel tube restrains this expansion, putting the steel tube in tension and the concrete in compression, effectively inhibiting expansion cracking of the concrete. This reduces ion transport channels and delays ion migration into the interior. A larger wall thickness (i.e., a higher steel ratio) provides a stronger circumferential confinement, thereby increasing concrete compactness and inhibiting ion ingress. However, the improvement in confinement stress due to wall thickness is limited, thus slightly enhanceing its hindering effect on ion diffusion. As sulfate concentration and C₃A content increase, the formation of expansive sulfate products such as ettringite increases, leading to a higher confinement stress. This effectively inhibits expansion cracking caused by erosion, thereby slowing down ion diffusion.

Under sulfate erosion, steel tube confinement effectively inhibits expansion cracking of concrete caused by expansive products such as ettringite. As the erosion age increases, the increase in sulfate ion concentration significantly accelerates the chemical erosion process, promoting the formation of gypsum crystals. This reaction consumes calcium hydroxide in the system and triggers the decalcification and decomposition of calcium silicate hydrate (C-S-H) gel, leading to a noticeable discoloration of the paste structure. As the stability of hydration products decreases, the microstructure of the material deteriorates, manifested by an increase in the proportion of harmful pores and total porosity. The evolution of the pore structure further alters transport pathways, forming fast channels for ion migration, ultimately enhancing the transport efficiency and erosion diffusion range of sulfate ions within the concrete. Based on this mechanism, a time-varying porosity sulfate ion transport model for concrete considering the effect of steel tube confinement can be established.

Conclusions

Under sulfate erosion, the steel tube could restrain a concrete expansion through the confinement effect, putting itself in tension and the concrete in compression, thereby inhibiting cracking. Steel tube confinement could reduce sulfate ion content and diffusion coefficient in concrete. Increasing C₃A content, sulfate concentration, or steel tube wall thickness further decreased sulfate ion content and diffusion coefficient.

A time-varying porosity-based sulfate ion diffusion model was established, accurately predicting sulfate ion concentration in steel tube-confined concrete under sulfate erosion.

Key words

sulfate erosion / steel tube confinement / sulfate ion transport / transport model

引用本文

曹杰荣, 金鸣, 丁庆军, 赵海涛, 庄智杰, 刘加平. 钢管约束混凝土中硫酸根离子传输特征与扩散模型. 硅酸盐学报, 2026 , 54 (2) : 611 -622 . DOI: 10.14062/j.issn.0454-5648.20250602

Jierong CAO, Ming JIN, Qingjun DING, Haitao ZHAO, Zhijie ZHUANG, Jiaping LIU. Transport Characteristics and Diffusion Model of Sulfate Ions in Steel Tube Confined Concrete[J]. Journal of the Chinese Ceramic Society, 2026 , 54 (2) : 611 -622 . DOI: 10.14062/j.issn.0454-5648.20250602

基金

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国家自然科学基金项目(U52293430; 52379118; 52508254)
广西科技重大专项项目(AA23062034)
淮河入海水道二期工程枢纽建设质量及安全保障提升关键技术研究(RHSD2/FW-2024-03)
国家资助博士后研究人员计划(GZC20252110)

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2026年第54卷第2期

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文章信息

doi: 10.14062/j.issn.0454-5648.20250602

接收时间：2025-08-13
首发时间：2026-10-27
出版时间：2026-02-20

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出版历史

收稿日期：2025-08-13
修回日期：2025-10-13

基金

国家自然科学基金项目(U52293430; 52379118; 52508254)

广西科技重大专项项目(AA23062034)

淮河入海水道二期工程枢纽建设质量及安全保障提升关键技术研究(RHSD2/FW-2024-03)

国家资助博士后研究人员计划(GZC20252110)

作者信息

^1．东南大学材料科学与工程学院，南京 211189

^2．东南大学，重大基础设施工程材料全国重点实验室，南京 211103

^3．武汉理工大学材料科学与工程学院，武汉 430070

^4．河海大学土木与交通学院，南京 210024

^5．江苏苏博特新材料股份有限公司，南京 211103

通讯作者:

刘加平（1967—），男，博士，教授。

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https://castjournals.cast.org.cn/joweb/gsyxb/CN/10.14062/j.issn.0454-5648.20250602

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2种不同金属材料的力学参数

科 Family	属数 Number of genus	种数 Number of species	占总种数比例 Percentage of total species (%)	属 Genus	种数 Number of species	占总种数比例 Percentage of total species (%)
鹅膏菌科Amanitaceae	2	11	5.26	鹅膏菌属 Amanita	10	4.78
小菇科 Mycenaceae	2	12	5.74	丝盖伞属 Inocybe	5	2.39
多孔菌科 Polyporaceae	8	14	6.70	蜡蘑属 Laccaria	5	2.39
红菇科 Russulaceae	3	23	11.00	小皮伞属 Marasmius	6	2.87
				小菇属 Mycena	11	5.26
				光柄菇属 Pluteus	5	2.39
				红菇属 Russula	17	8.13
				栓菌属 Trametes	5	2.39

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