硅酸盐学报

约束对单面盐冻混凝土内部损伤的影响：微裂纹萌生与扩展

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高志浩 ¹^,²^,³ , 王振地 ³ , 王玲 ³

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): 768-780

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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) : 768 -780

约束对单面盐冻混凝土内部损伤的影响：微裂纹萌生与扩展

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高志浩¹^,²^,³, 王振地³, 王玲³

作者信息

^1．北京交通大学土木建筑工程学院，北京 100044

^2．中交公路长大桥建设国家工程研究中心有限公司，北京 100011

^3．中国建筑材料科学研究总院有限公司，北京 100024

通讯作者:

王振地（1984—），男，教授级高级工程师。

作者简介:

高志浩（1992—），男，博士。

Influence of Restraint on Salt Frost Damage of Concrete: Initiation and Propagation of Microcracks

Zhihao GAO¹^,²^,³, Zhendi WANG³, Ling WANG³

Affiliations

^1.Beijing Jiaotong University, School of Civil Engineering, Beijing 100044, China

^2.China Communications Construction Company Highway Bridges National Engineering Research Centre Co., Ltd., Beijing 100011, China

^3.China Building Materials Academy, Beijing 100024, China

Corresponding Author:

WANG Zhendi (1984-), male, Professor. E-mail: wzhendi@163.com

GAO Zhihao (1992-), male, Ph.D. E-mail: zhihao369@foxmail.com

出版时间: 2026-02-20 doi: 10.14062/j.issn.0454-5648.20250197

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摘要

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现行单面盐冻试验中，混凝土试件处于自由形变状态，这与混凝土的实际服役状态不符，因此混凝土抗冻性研究有必要考虑实际服役中的约束作用。本工作研究约束作用对单面盐冻混凝土孔结构损伤及微裂纹萌生与扩展的影响及机理。利用改进数字图像处理方法，实现了水灰比0.60的约束态和自由态混凝土在单面盐冻作用下孔结构与微裂纹的单独分析。每8次单面盐冻循环测试混凝土的孔结构和微裂纹，计算获得最可几孔径（d_M）、平均孔径（d）、孔径分布标准偏差（d_σ）、劣化孔数量占比（P_dam）、微裂纹平均长度（L_mean）和微裂纹平均宽度（W_mean）；实时监测32次盐冻循环过程中混凝土应变，计算获得残余应变（S_n）。结果表明约束态混凝土的d_M、đ、d_σ、P_dam、L_mean和S_n分别比自由态混凝土少11%、10%、5%、7%、7%、30%；通过计算孔均微裂纹数量和长度发现，与自由态混凝土相比，约束态混凝土内微裂纹更倾向于扩展宽度而非萌生新的微裂纹。灰色关联度显示，约束作用通过限制盐冻混凝土的孔径扩张，抑制微裂纹萌生，从而减少了盐冻作用诱导的残余应变。

关键词

约束态混凝土 / 单面盐冻 / 内部损伤 / 孔结构 / 微裂纹

Abstract

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Introduction

The freezing and thawing (F-T) is one of the main threats for concrete in cold regions. The migration and phase transformation of moisture inside concrete induced by the F-T cycles is the origin of surface scaling and internal damage, which can induce the deformation of the matrix. The deterioration process of concrete can be further accelerated with the deicing salt. Previous studies usually followed the standardized methods. The deformation of concrete during the F-T cycles is free, which is different from the concrete in a service state. The concrete specimen is only equivalent to one unit in the concrete member. All concrete units undergo a deformation subjected to the F-T cycles, limiting the free deformation of adjacent concrete units. The limitation between adjacent concrete units is a form of restraint. Some restraint devices are developed to limit the deformation of concrete during F-T cycles. Conventional concrete frost resistance tests underestimate surface damage but overestimate internal damage due to the lack of consideration for restraint. However, the impact of restraint on the deterioration of concrete pore structure and the initiation/propagation of microcracks due to F-T cycles is unclear. Characterizing the internal damage of concrete is an important way to investigate the mechanism of concrete frost damage. The common method is to use digital image processing (DIP) to analyze the deterioration of concrete microstructure induced by F-T cycles, which has the advantages of convenient sample preparation and unrestricted sample size. In recent years, DIP methods have been also combined with morphological image processing to form a method of segmenting, extracting, and quantitatively analyzing for pores and microcracks that rely on "shape factors" to identify pores and microcracks. This paper was to focus on the restrained and unrestrained concrete as research objects. The pore structure and microcrack parameters were statistically analyzed after the single-side salt F-T test. The residual strain of concrete was calculated. The comparative analysis of the differences between two types of concrete in terms of pore structure deterioration and microcrack initiation was carried out to elucidate the influence of restraint on the deterioration of concrete pore structure and microcracks. The results could be expected to guide the mix design of frost resistant concrete in cold regions, ensuring the long service life of concrete materials.

Methods

P. I 42.5 cement, natural river sand with a fineness modulus of 2.68, and graded stone by uniformly mixing the crushed stone with 5-10 mm and 10-20 mm in a mass ratio of 4∶6 were used to prepare fresh concrete at a water/cement ratio of 0.60. The 28 d cube compressive strength of the concrete specimen was 28.3 MPa. Two groups of moulds were used to cast concrete specimens. For unrestrained specimens, cylindrical plastic moulds with a diameter of 100 mm and a height of 70 mm were used. For restraint specimen, a restraint device was used. The curing and pre saturation of concrete specimens were carried out according to the salt freezing method in the CIF test and the GB/T 50082—2009. The CDF/CIF TESTER produced by Schleibinger Geräte was used to provide single-side salt F-T cycles. After each 4 F-T cycles, the DIP sample was prepared. The processing of digital images included shooting, binarization, segmentation and extraction of region of interest (ROI), and skeleton. The obtained pore parameters included pore diameter distribution, most probable pore diameter (d_M), mean pore diameter (đ), standard deviation of pore diameter (d_σ), and percentage of damaged pores (P_dam). The obtained microcrack parameters included the mean length (L_mean) and mean width (W_mean) of microcracks.

Results and discussion

The d_M , đ , d_σ and P_dam of both restrained and unrestrained concretes increase with the F-T cycles. After the 32 F-T cycles, the d_M , đ , d_σ , and P_dam of the restrained concrete are 11%, 10%, 5%, and 7% smaller than those of the unrestrained concrete, respectively. The results indicate that the restraint limits the expansion of the pores due to the F-T cycles. During the cooling process, the restraint weakens the water migration inside concrete via limiting the shrinkage deformation of concrete, thereby reducing the pore diameter shrinkage induced by water migration, the saturation of larger pores and thereby reducing the crystallization pressure. The restraint reduces the pore expansion and microcrack initiation of restrained concrete. The L_mean of restrained and unrestrained concretes increases with the F-T cycles. After the 32 F-T cycles, the L_mean of restrained concrete is 7% less than that of unrestrained concrete. The W_mean of unrestrained concrete decreases, but the W_mean of restrained concrete increases with the increase of F-T cycles. The restraint changes the evolution of microcracks in concrete due to the F-T cycles, resulting in macroscopic differences in the frost damage of the two types of concretes. Furthermore, after the 32 F-T cycles, the S_n of restrained concrete is 30% less than that of unrestrained concrete. The grey correlation degree shows that the pore expansion and microcrack length induced by F-T cycles are the main factors leading to the increase of residual strain. A correlation between the expansion of pore diameter inside restrained concrete and the increase in residual strain is greater, which is related to the weakening of water migration under the restraint.

Conclusions

The restraint had a significant inhibitory effect on the pore diameter expansion and microcrack initiation of concrete subjected to single-side salt freezing and thawing. The restrained concrete was to release stress through the expansion of microcrack width, being a key mechanism for reducing internal damage induced by the single-side salt freezing and thawing cycles. The main reason for the increase in residual strain of concrete induced by the F-T cycles could be the expansion of pore diameter and the growth of microcrack length.

Key words

restraint concrete / single-side freezing and thawing / internal damage / pore parameters / microcrack

引用本文

高志浩, 王振地, 王玲. 约束对单面盐冻混凝土内部损伤的影响：微裂纹萌生与扩展. 硅酸盐学报, 2026 , 54 (2) : 768 -780 . DOI: 10.14062/j.issn.0454-5648.20250197

Zhihao GAO, Zhendi WANG, Ling WANG. Influence of Restraint on Salt Frost Damage of Concrete: Initiation and Propagation of Microcracks[J]. Journal of the Chinese Ceramic Society, 2026 , 54 (2) : 768 -780 . DOI: 10.14062/j.issn.0454-5648.20250197

基金

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“十四五”国家重点研发计划青年科学家项目(2022YFB3708700)

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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.0454-5648.20250197

接收时间：2025-03-24
首发时间：2026-10-27
出版时间：2026-02-20

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收稿日期：2025-03-24
修回日期：2025-04-17

基金

“十四五”国家重点研发计划青年科学家项目(2022YFB3708700)

作者信息

^1．北京交通大学土木建筑工程学院，北京 100044

^2．中交公路长大桥建设国家工程研究中心有限公司，北京 100011

^3．中国建筑材料科学研究总院有限公司，北京 100024

通讯作者:

王振地（1984—），男，教授级高级工程师。

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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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