硅酸盐学报

基于声发射的高原大温差环境桥墩混凝土开裂机理

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董昊良 ¹^,² , 李化建 ¹^,² , 杨志强 ¹^,² , 黄法礼 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): 719-730

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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) : 719 -730

基于声发射的高原大温差环境桥墩混凝土开裂机理

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董昊良¹^,², 李化建¹^,², 杨志强¹^,², 黄法礼¹^,²

作者信息

^1．中国铁道科学研究院集团有限公司铁道建筑研究所，北京 100081

^2．高速铁路轨道系统全国重点实验室，北京 100081

通讯作者:

李化建（1976—），男，博士，研究员。

作者简介:

董昊良（1999—），男，博士研究生。

Study on Cracking Mechanism of Pier Concrete in High Altitude Large Temperature Difference Environments Based on Acoustic Emission

Haoliang DONG¹^,², Huajian LI¹^,², Zhiqiang YANG¹^,², Fali Huang¹^,²

Affiliations

^1.Railway Engineering Research Institute, China Academy of Railway Science Corporation Limited Beijing 100081, China

^2.State Key Laboratory Track Technology of High-Speed Railway, Beijing 100081, China

Corresponding Author:

LI Huajian (1976-), male, Ph.D., Professor. E-mail: chinasailor@163.com

DONG Haoliang (1999-), male, Doctoral candidate. E-mail: dhlCARS@163.com

出版时间: 2026-02-20 doi: 10.14062/j.issn.0454-5648.20250658

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摘要

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混凝土结构开裂是高原大温差环境桥墩亟待解决的关键技术难题。本工作提出了一种模拟高原昼夜温差环境的桥墩混凝土开裂试验方法，证实了声发射技术在评估混凝土内部裂缝萌生与损伤演化的可行性，揭示了大温差条件下桥墩混凝土结构的开裂机制。结果表明：大温差环境桥墩混凝土结构呈现3阶段损伤发展规律，即微裂缝（损伤）累积阶段、宏观开裂阶段和裂缝扩展阶段。升、降温使处于第1阶段和第3阶段桥墩混凝土结构的损伤或裂缝进一步累积和发展，而宏观开裂现象多发生于自80～60 ℃的降温阶段，其原因是降温过程中混凝土表层收缩，但因中部仍保持膨胀状态而产生了更多损伤。同时，声发射监测数据证明，温度循环引起的疲劳拉应力是导致混凝土损伤累积和开裂的主要因素，且在温度循环过程中混凝土内部产生的拉伸裂缝占比超过90%。

关键词

高原大温差环境 / 桥墩混凝土 / 声发射 / 开裂特征 / 损伤演变

Abstract

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Introduction

In regions characterized by excessively high diurnal temperature variations and strong radiation (high-temperature difference environments), concrete structures face heightened risks of cracking during service. Excluding the influence of hydration heat released by the concrete itself, energy absorption from the external environment during service is identified as the direct cause of concrete cracking. Surface cracking represents one of the primary failure modes for concrete in plateau regions with large temperature differences. In such environments, concrete structures are susceptible to cracking not only due to wind-induced drying shrinkage but also from intense solar radiation and excessive diurnal temperature fluctuations. Notably, vertical structures like bridge piers exhibit complex cracking patterns, with cracks often forming a crisscross network on the surface. As a non-homogeneous composite material with low thermal conductivity, concrete experiences internal/external temperature gradients and thermal stresses arising from differences in the coefficients of thermal expansion between cementitious systems and aggregates, which constitute the principal mechanisms for structural cracking. Existing methods for detecting and identifying cracks in concrete structures include manual visual inspection, infrared thermography, and Digital Image Correlation (DIC) techniques. Manual visual inspection, while the most direct and simplest method, suffers from low accuracy due to human subjectivity. Infrared thermography identifies cracks based on thermal conductivity differences between cracked and intact concrete; however, its performance is significantly affected by ambient temperature, humidity, and wind speed, making it unsuitable for regions with dramatic climatic variations like high-temperature-difference environments. DIC, a widely used image analysis tool, precisely captures strain field distributions in concrete under load, enabling accurate crack localization and evaluation. Nevertheless, DIC is limited to surface observations and cannot monitor the development of internal micro-cracks or damage. Additionally, its stringent requirements for ambient lighting hinder its application in long-term field monitoring of actual structures.

Methods

The raw materials used in this study included cement, coarse aggregates, fine aggregates, and water. The cement was P·O 42.5 ordinary Portland cement. The coarse aggregates consisted of continuous graded crushed stones with particle sizes ranging from 5 mm to 10 mm and 10 mm to 20 mm. The fine aggregates were natural river sand with a fineness modulus of 2.8 and graded in Zone II. To accelerate the simulation of concrete cracking characteristics under extreme temperature environments, a "square-inner-circle-outer" composite concrete structure was designed for temperature cycling tests. During the temperature cycling process, stress concentration induced by temperature gradients occurs at the edges and corners of the internal prismatic component, amplifying the thermal stress-induced damage to the concrete.

Acoustic Emission (AE) Technology exhibits unique advantages in monitoring concrete cracking under high-temperature difference environments. Compared to other detection/monitoring methods, AE offers real-time crack capture, high precision, crack localization, fracture type classification, and minimal environmental interference. Radhika et al. employed AE analysis to investigate fracture behavior and damage mechanisms in concrete beams under static and fatigue loads. Li et al. utilized AE to study damage degradation patterns and crack types in concrete under varying fatigue stress levels, categorizing the fatigue failure process into four stages. Jiao et al. applied AE to analyze the damage characteristics of steel fiber, basalt fiber, and glass fiber-reinforced manufactured sand concrete under load. However, current AE applications predominantly focus on damage assessment under mechanical loads, with its feasibility for internal damage monitoring and cracking state evaluation in concrete structures under high-temperature-difference environments remaining unverified.

First, a prismatic specimen with dimensions of 100 mm × 100 mm × 400 mm was cast according to the mix design and cured in a standard curing environment for 28 d. The cured prismatic specimen was then placed at the center of a cylindrical mold with a diameter of 200 mm and a height of 400 mm. Fresh concrete with the same mix design was cast into the mold. After 1 day of indoor membrane-covered curing, the specimen was demolded and transferred to a standard curing environment for an additional 7 d, completing the preparation of the "square-inner-circle-outer" composite concrete specimen. Prior to testing, concrete specimens cured for 7 d were dried for 21 d under constant temperature and humidity conditions (20±2) ℃ and relative humidity (60±5)%. Subsequently, the specimens were polished smooth and thoroughly cleaned to ensure effective sensor adhesion and facilitate observation of surface crack development. Eight sensors were attached to both the upper and lower sections of the lateral surface of cylindrical specimens, coupled to the sample interface area using high-temperature-resistant silicone couplers. To investigate the evolution of cracking damage in concrete under extreme temperature cycling, this study set the environmental chamber temperature to cycle between 0 ℃ and 80 ℃, with each cycle lasting 4 h. Concrete specimens standardly cured for 7 d underwent 40 consecutive temperature cycles in the chamber, with AE data acquisition covering the entire duration of each temperature cycle.

Results and discussion

During the 40 temperature cycles, the acoustic emission AE equipment captured a total of 539 events generated by concrete stress release or crack propagation, which occurred throughout the entire temperature cycling process. High-amplitude signals indicate intense energy release at crack tips, typically associated with rapid crack propagation or unstable cracking. Most AE signals exhibited stable amplitudes between 50 dB and 80 dB during temperature cycling, reflecting the gradual accumulation of damage and crack extension under thermal fatigue stress induced by repeated expansion-contraction cycles. High-amplitude AE signals predominantly occurred during temperature rises to 60-80 ℃, demonstrating that concrete under thermal cycling is more susceptible to rapid damage accumulation or stable crack propagation at elevated temperatures. A concentrated increase in AE event counts was observed during the 16th temperature cycle, coinciding with a peak cumulative energy of 1943 aJ, indicating significant macroscopic cracking. Furthermore, the cumulative AE energy effectively characterizes the overall structural damage process. A sharp rise in cumulative energy over time correlates with the formation of fracture process zones, and abrupt changes in the energy-time curve slope serve as a criterion for microcrack coalescence into macrocracks.

Based on energy characteristics, the concrete damage and cracking process can be divided into three stages: microcrack accumulation, macrocrack initiation, and crack propagation. After multiple temperature cycles, internal microcracks interconnect during the cooling phase due to shrinkage stresses, ultimately forming macrocracks. This phenomenon is validated by the concentrated energy release and abrupt slope changes in the cumulative energy curve during cooling. Both microcracks and macrocracks in concrete under thermal cycling are predominantly tensile in nature, with over 90% of cracks attributed to thermal fatigue tensile stresses. In summary, the composite concrete structure designed in this study can effectively evaluate the temperature cycling resistance of concrete. The number of temperature cycles corresponding to the onset of macrocracks (Stage II) serves as a quantitative metric for assessing concrete cracking resistance.

Conclusions

This paper addresses the damage and cracking of bridge pier concrete under plateau high-temperature-difference environments. A testing method simulating concrete cracking in such environments was proposed, combining AE technology to achieve real-time monitoring and quantitative analysis of internal damage evolution. The damage mechanisms under high-temperature-difference conditions were elucidated. The key conclusions are as follows: 1) Micro-cracks initiate in bridge pier concrete during the early stages of temperature cycling under high-temperature-difference environments. The cracking process can be divided into three stages: micro-crack (damage) accumulation, macroscopic cracking, and crack propagation. 2) During the micro-crack (damage) accumulation and crack propagation stages, both temperature rise and fall exacerbate damage or crack development in the concrete. However, macroscopic cracking predominantly occurs during the cooling phase from 80 ℃ to 60 ℃. This is attributed to the faster surface temperature reduction compared to the interior, creating a non-uniform deformation effect characterized by "outer shrinkage and inner expansion." 3) Temperature fatigue tensile stress is identified as the primary cause of bridge pier concrete cracking under high-temperature-difference environments. Over 90% of the total cracks observed under temperature cycling are tensile cracks. Furthermore, the failure mode exhibits continuous damage accumulation and propagation along macroscopic primary cracks.

Key words

plateau environment with large temperature differences / bridge pier concrete / acoustic emission / cracking characteristics / damage evolution

引用本文

董昊良, 李化建, 杨志强, 黄法礼. 基于声发射的高原大温差环境桥墩混凝土开裂机理. 硅酸盐学报, 2026 , 54 (2) : 719 -730 . DOI: 10.14062/j.issn.0454-5648.20250658

Haoliang DONG, Huajian LI, Zhiqiang YANG, Fali Huang. Study on Cracking Mechanism of Pier Concrete in High Altitude Large Temperature Difference Environments Based on Acoustic Emission[J]. Journal of the Chinese Ceramic Society, 2026 , 54 (2) : 719 -730 . DOI: 10.14062/j.issn.0454-5648.20250658

基金

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国家自然科学基金(52438002; 52208299)
中国铁道科学研究院集团有限公司院基金(2024YJ207)
科学探索奖XPLORER PRIZE

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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.0454-5648.20250658

接收时间：2025-09-05
首发时间：2026-10-27
出版时间：2026-02-20

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收稿日期：2025-09-05
修回日期：2025-11-12

基金

国家自然科学基金(52438002; 52208299)

中国铁道科学研究院集团有限公司院基金(2024YJ207)

科学探索奖XPLORER PRIZE

作者信息

^1．中国铁道科学研究院集团有限公司铁道建筑研究所，北京 100081

^2．高速铁路轨道系统全国重点实验室，北京 100081

通讯作者:

李化建（1976—），男，博士，研究员。

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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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