硅酸盐学报

盐结晶侵蚀下水泥基材料孔隙结构与传输性能演变规律

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熊青香 ¹^,² , 刘清风 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): 470-483

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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) : 470 -483

盐结晶侵蚀下水泥基材料孔隙结构与传输性能演变规律

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熊青香¹^,², 刘清风¹^,²

作者信息

^1．上海交通大学海洋工程全国重点实验室，上海 200240

^2．上海市公共建筑和基础设施数字化运维重点实验室，上海 200240

通讯作者:

刘清风（1986—），男，博士，教授。

作者简介:

熊青香，上海交通大学船舶海洋与建筑工程学院助理研究员，硕士生导师、上海市浦江学者。2021年于法国国立应用科学院（INSA RENNES）取得博士学位，同年入职上海交通大学从事科研工作至今。担任国际SCI期刊Case Studies in Construction Materials和中文EI期刊材料导报的青年编委，兼任国际结构材料学会(RILEM)胶凝材料界面水分传输技术委员会（TC-MMS）专家委员、上海市土木工程学会工程材料专委会委员。主持国家自然科学基金、上海市浦江人才计划、中国博士后基金面上项目等国家/省部级纵向课题多项。近三年在CCR、CCC、CBM、CMS、MTENG-ASCE等建材领域国际权威期刊发表论文20余篇。主要研究方向为水泥基胶凝材料微结构建模与表征、多孔材料传质传输反应数值计算、混凝土结构材料耐久性、碱激发材料盐结晶理论研究。

熊青香（1992—），女，博士，助理研究员。

刘清风，上海交通大学教授、博士生导师，上海市公共建筑和基础设施数字化运维重点实验室副主任，国家优秀青年科学基金获得者、“十四五”国家重点研发计划项目青年首席科学家。担任Cement &Concrete Composites、Materials and Structures等7家国际SCI期刊及硅酸盐学报、建筑材料学报等6家中文EI期刊编委，并兼任RILEM、FIB、ACI、ICE、中国硅酸盐学会、中国土木工程学会、中国建筑学会、中国大坝工程学会等十余家学术组织的专家委员/理事。主要从事混凝土结构/材料耐久性研究，发表论文160余篇，SCI他引5000余次，H-index为46，连续多年入选Elsevier中国高被引学者、斯坦福大学全球前2%终身影响力科学家、中国知网TOP1%高被引学者。主持5项国家自然科学基金等国家／省部级纵向课题20余项，研究成果被纳入国际结构混凝土学会标准ModelCode 2020等5本中外标准规范，以第一完成人获中国建筑材料科学技术奖、中国硅酸盐学会青年科技奖、国际结构材料学会古斯塔沃·科洛内蒂奖章等重要奖项。

Salt Crystallization-Induced Pore Structure Evolution and Transport Properties Degradation in Cementitious Materials

Qingxiang XIONG¹^,², Qingfeng LIU¹^,²

Affiliations

^1.State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University, Shanghai 200240, China

^2.Shanghai Key Laboratory for Digital Maintenance of Buildings and Infrastructure, Shanghai 200240, China

Corresponding Author:

LIU Qingfeng (1986-), male, Ph.D., Professor. E-mail: liuqf@sjtu.edu.cn

XIONG Qingxiang (1992-), female, Ph.D., Assistant Researcher. E-mail: qingxiangxiong@sjtu.edu.cn

出版时间: 2026-02-20 doi: 10.14062/j.issn.0454-5648.20250467

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摘要

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水泥基材料的孔隙结构是决定其耐久性能的关键因素。盐结晶作为典型的耐久性劣化诱因，通过物理与化学反应改变孔隙结构并影响传输性能。为解析这一复杂过程，本工作首先构建了盐结晶作用下孔隙填充路径及孔隙结构演变数学模型；在此基础上提出了固有渗透性能预测方法，并考虑水饱和度和与气体分子滑移效应的影响，构建了非饱和状态下的气体渗透修正模型；最终，通过耦合孔隙结构特征参数和渗透系数的关系，建立了吸水率及毛细吸水高度预测模型，并采用第三方试验数据验证模型的可靠性。研究结果表明：盐结晶空间分布与外部环境相对湿度及内部干湿界面位置密切相关，非线性填充路径模型可反映局部孔径分布演变规律。其次，采用渗透模型成功预测了6组砂浆的固有渗透系数和3组砂浆的非饱和气体渗透系数，证实了水饱和临界阈值的存在，当超过该阈值时气体传输性能显著衰减。最后，发现吸水性能与孔隙结构呈正相关，与相对湿度呈负相关，且在盐结晶过程中孔隙率的增大会强化吸水性能，这一趋势在高湿度环境（RH>80%）下尤为突出。

关键词

孔隙结构 / 盐结晶 / 非饱和状态 / 渗透系数 / 吸水率

Abstract

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Introduction

The durability of cementitious materials in coastal environments is fundamentally challenged via salt crystallization, and a prevalent deterioration mechanism alters pore structure and degrades transport properties. While total porosity is commonly considered, pore size distribution (PSD) proves more critical. It is indicated that large pores (i.e., 0.1-5.0 μm) facilitate salt solution ingress, while small pores (i.e., <0.1 μm) generate high crystallization pressures. However, the existing models often fail to capture the complex crystallization at wet-dry interfaces in cement-based materials. This study was to develop a comprehensive mathematical framework using log-normal distributions to characterize the initial PSD and model its evolution under salt attack. We established predictive methods for permeability and sorptivity that could account for pore structure evolution, with validation through independent experiments. In addition, this study also analyzed the performance variations under different testing conditions and investigated water absorption behavior during salt crystallization.

Methods

The research methodology was founded on theoretical modeling and third-party experimental validation. First, a mathematical model for pore structure evolution was proposed. The initial pore size distribution (PSD) of cementitious materials was described by a composite log-normal distribution function, dividing pores into four families, i.e., large interlayer pores, gel pores, small capillary pores, and large capillary pores. Two distinct pore-filling paths during salt crystallization were hypothesized, i.e., A uniform (U) filling model, where salt deposits uniformly across all pores with a constant corrosion amount, and a non-linear (NL) filling model, where crystallization is concentrated near the wet-dry interface, with a corrosion amount proportional to the initial pore radius. The position of this critical interface was determined based on ambient relative humidity (RH) using the Kelvin-Laplace equation.

Subsequently, a novel intrinsic permeability prediction model (i.e., the Pore Size Distribution-Permeability (PSD-K) model) was derived from the Hagen-Poiseuille equation, explicitly incorporating total porosity, pore tortuosity, and the full PSD. For unsaturated conditions, this model was extended to predict gas permeability via integrating the wet-dry interface parameter r_c. Further refinements accounted for gas slippage effects and the influence of water saturation based on the Van Genuchten-Mualem model, yielding an apparent gas permeability. Finally, a sorptivity and capillary rise height model was formulated via coupling the PSD-K model with capillary pressure described by the Young-Laplace equation. All models were rigorously validated with the published experimental data from various mortar specimens subjected to salt exposure and drying-wetting cycles.

Results and discussion

The validation against MIP data from a PC specimen after Na₂SO₄ immersion reveals a porosity reduction from 25.9% to 16.9%. The nonlinear (NL) filling model demonstrates a superior capability in capturing localized pore structure evolution, compared to the uniform (U) model. For a calculated critical radius of 64.9 nm at RH of 96.5%, the NL model accurately predicts a pore modification in the size range of 20-100 nm, dominating transport processes. However, discrepancies occur in smaller (i.e., <20 nm) and larger (i.e., >100 nm) pore regions, primarily due to the oversimplified assumption of uniform hydration product deposition. This indicates a need for future models to incorporate non-uniform hydration effects for improved prediction accuracy.

After the establishment of a reliable pore structure evolution model, we further evaluate its impact on the key transport property indicator-permeability coefficient. The PSD-K model can predict an intrinsic permeability for six mortar groups, having reasonable agreement with gas intrusion data (i.e., 0.66-7.51×10^-17m² for M40-M60). However, the PSD-K and the Katz-Thompson (K-T) models both overestimate water-based measurements by 1-3 orders of magnitude, revealing fundamental test-method dependencies. This discrepancy stems from C-S-H gel swelling during water intrusion, which compresses pore space versus enhanced flow due to gas slippage effects in dried specimens. For unsaturated conditions, the modified model confirms a critical water saturation threshold (i.e., about 0.8), beyond which gas permeability decreases dramatically as a liquid phase blocks continuous pore networks. The PSD-K model effectively tracks the permeability-porosity relationship during salt crystallization, demonstrating the model capability in simulating the performance degradation under chemical attack.

Beyond permeability, capillary water absorption represents another crucial process driving salt solution ingress, whose evolution patterns are similarly investigated. The sorptivity model shows a correlation with the experimental data for mortar specimens with varying slag contents. The results indicate that the sorptivity of GBFS0 mortar (i.e., 39.4% porosity) exhibits approximately four times higher than that of GBFS50 mortar (i.e., 8.4% porosity) due to its greater volume of large capillary pores (i.e., >100 nm) that dominate absorption processes. The results of environmental analysis reveal a negative correlation between RH and sorptivity as a higher initial water saturation reduces capillary driving forces, particularly in finer pores. Furthermore, salt-induced porosity increases significantly an enhanced sorptivity, with this effect being markedly pronounced under high-humidity conditions (RH > 80%) where the wet-dry front occupies larger pores, making absorption more sensitive to pore volume changes. These findings can provide crucial insights for predicting salt damage risks in various service environments.

Conclusions

This study established a theoretical framework for quantifying salt crystallization impacts on cementitious materials. The key findings demonstrated that the nonlinear pore-filling model could predict pore structure evolution, particularly in the critical size range of 20-100 nm, with the MIP data confirming a porosity reduction from 25.9% to 16.9% and crystallization localization at wet-dry interfaces. The PSD-K model could predict an intrinsic permeability, showing a reasonable agreement with the gas intrusion data (i.e., ~7.51×10^-17 m² for M60) and identifying a critical water saturation threshold (i.e., ~0.8) for gas transport. The sorptivity model captured a fourfold difference between high-and low-porosity mortars, revealing that salt-induced porosity increase coupled with a high humidity (i.e., RH>80%) drastically enhanced water absorption. This integrated framework could provide an effective tool for durability assessment of concrete in salt environments.

Key words

pore structure / salt crystallization / unsaturated state / permeability / sorptivity

引用本文

熊青香, 刘清风. 盐结晶侵蚀下水泥基材料孔隙结构与传输性能演变规律. 硅酸盐学报, 2026 , 54 (2) : 470 -483 . DOI: 10.14062/j.issn.0454-5648.20250467

Qingxiang XIONG, Qingfeng LIU. Salt Crystallization-Induced Pore Structure Evolution and Transport Properties Degradation in Cementitious Materials[J]. Journal of the Chinese Ceramic Society, 2026 , 54 (2) : 470 -483 . DOI: 10.14062/j.issn.0454-5648.20250467

基金

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国家重点研发计划项目(2024YFB3715100)
国家自然科学基金青年项目(52208268)

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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.0454-5648.20250467

接收时间：2025-06-13
首发时间：2026-10-27
出版时间：2026-02-20

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收稿日期：2025-06-13
修回日期：2025-07-18

基金

国家重点研发计划项目(2024YFB3715100)

国家自然科学基金青年项目(52208268)

作者信息

^1．上海交通大学海洋工程全国重点实验室，上海 200240

^2．上海市公共建筑和基础设施数字化运维重点实验室，上海 200240

通讯作者:

刘清风（1986—），男，博士，教授。

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https://castjournals.cast.org.cn/joweb/gsyxb/CN/10.14062/j.issn.0454-5648.20250467

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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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