硅酸盐学报

真空暴露对聚合物—纤维改性混凝土力学性能的影响

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龙朝飞 ¹ , 龙广成 ¹ , 胡正勇 ² , 唐卓 ¹ , 张玉庭 ¹ , 封杰 ¹ , 杜航宇 ¹ , 彭磊 ¹ , 蒋定 ¹

硅酸盐学报 | 研究论文 2026,54(1): 243-257

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硅酸盐学报 |研究论文 2026 , 54 (1) : 243 -257

真空暴露对聚合物—纤维改性混凝土力学性能的影响

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龙朝飞¹, 龙广成¹, 胡正勇², 唐卓¹, 张玉庭¹, 封杰¹, 杜航宇¹, 彭磊¹, 蒋定¹

作者信息

^1．中南大学土木工程学院，长沙 410075

^2．中铁六局集团丰桥桥梁有限公司，北京 100070

通讯作者:

龙广成（1973—），男，博士，教授。

作者简介:

龙朝飞（1997—），男，博士研究生。

Effect of Vacuum Exposure on Mechanical Properties of Polymer-Fiber Modified Concrete

Zhaofei LONG¹, Guangcheng LONG¹, Zhengyong HU², Zhuo TANG¹, Yuting ZHANG¹, Jie FENG¹, Hangyu DU¹, Lei PENG¹, Ding JIANG¹

Affiliations

^1.School of Civil Engineering, Central South University, Changsha 410075, China

^2.Fengqiao Bridge Co., Ltd. of China Railway Sixth Group Co., Ltd., Beijing 10070, China

Corresponding Author:

LONG Guangcheng (1973-), male, Ph.D., Professor. E-mail: longguangcheng@csu.edu.cn

LONG Zhaofei (1997-), male, Doctoral candidate. E-mail: lzf2033195@163.com

出版时间: 2026-01-20 doi: 10.14062/j.issn.0454-5648.20250466

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摘要

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针对超高速磁悬浮管道等真空工程中服役混凝土脆性增大问题，本工作提出聚合物与非金属纤维协同改性策略。通过可再分散乳胶粉（RDP）、丁苯乳胶改性乳化沥青（MEA）与超高分子量聚乙烯纤维（PEF）、碳纤维（CF）的复合掺加，并结合颗粒紧密堆积模型设计制备了一类高密实、高韧性混凝土。利用声发射技术与Kneedle拐点识别算法，系统揭示了常压暴露（AE）及真空暴露（VE）对改性混凝土力学损伤行为的影响机制。结果表明：AE和VE均提升了混凝土的抗压强度（最高30.9%），但VE对抗弯强度不利（降幅达22.8%）；对照组混凝土在VE下的压缩韧性和弯曲韧性显著降低，而通过聚合物和纤维改性可以有效避免此问题。扫描电子显微镜观察发现，真空可强化聚合物的成膜效应，有效桥接水化产物并与纤维形成高韧性的三维网络结构，从而抑制微裂纹扩展；其中RDP与PEF的组合可发挥最优协同增韧效果，使试件峰后韧性得以较好保持。声发射特征参数分析结果表明，VE 使损伤预警时间提前，并加剧了纤维-基体界面的黏结滑移，进而产生更多的剪切裂纹信号。CF在拔出过程中易发生脆断，而PEF可以通过滑移变形耗散能量，与聚合物协同抑制多尺度裂纹扩展，适用于在真空环境下服役。

关键词

混凝土 / 真空暴露 / 聚合物 / 纤维 / 声发射

Abstract

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Introduction

Vacuum environment engineering has attracted significant attention due to its revolutionary applications in ultra-high-speed transportation, space technology, and frontier physics experiments. Concrete, as the most widely used construction material globally, remains an ideal choice for constructing ultra-high-speed vacuum pipelines and space bases. However, under harsh vacuum conditions, concrete faces severe challenges such as rapid dehydration, increased brittleness, drying shrinkage cracking, and reduced durability. To effectively enhance the vacuum service performance of concrete, this study designs a type of polymer-fiber modified concrete that leverages the film-forming toughening effects of polymers and the high strength and high elastic modulus characteristics of fibers to effectively mitigate the brittle behavior of concrete when exposed to vacuum. Utilizing acoustic emission techniques, the study examines how vacuum conditions, polymers, and fibers affect the mechanical properties of the modified concrete, further elucidating the underlying mechanisms with scanning electron microscopy (SEM) imaging.

Methods

Based on the principles of dense particle packing and gradational hydration, a mix design was developed for the binder system (including cement, fly ash, slag, and silica fume). Redispersible latex powder (RDP) and styrene-butadiene latex-modified emulsified asphalt (MEA) were selected as the polymer modification materials, while ultra-high molecular weight polyethylene fibers (PEF) and carbon fibers (CF) were chosen as the fiber reinforcement materials. To balance the strength and toughness of the concrete, the polymer dosage was set at 3.5% by mass of the binder, and the fiber volume fraction at 0.8%. A polycarboxylate-based superplasticizer was used at 1.2% by mass of the binder to ensure the workability of the fresh paste. The concrete was mixed using a dual-axis horizontal mixer. Initially, the coarse and fine aggregates and binder were dry-mixed for 1 min, then water and superplasticizer were added and mixed for 1 min. Finally, the polymer and fibers were incorporated and mixed for an additional 2-3 min to produce a fresh paste. The specimens were cured under standard conditions for 28 days before being exposed to either atmospheric exposure (AE) or vacuum exposure (VE) conditions.

AE was conducted in an ambient pressure room maintained at a temperature of (20±2) ℃ and a relative humidity of 55%-65%. VE was simulated using a homemade vacuum chamber with a vacuum pressure of approximately 100 Pa, a relative humidity of <10%, and a temperature essentially identical to that of the AE environment. In accordance with GB/T 50081-2019 "Standard Test Methods for the Physical and Mechanical Properties of Concrete," uniaxial compression tests and four-point bending tests were performed on specimens before and after exposure. Extensometers were used to record the axial and mid-span displacements of the specimens, and the corresponding stress-strain curves and load-displacement curves were plotted. During the mechanical performance tests, acoustic emission monitoring was conducted simultaneously. The mechanical damage characteristics of the concrete specimens were analyzed based on the acoustic emission signal intensity, b-value, and RA-AF plots. Finally, SEM was employed to observe the microstructure of the samples, revealing the degradation mechanism of concrete under vacuum exposure as well as the modification mechanism of the polymer-fiber combination.

Results and discussion

VE is beneficial to the compressive strength of the concrete but detrimental to its bending strength. Compared with SC, the concrete in the control group under VE shows a 3.3% increase in compressive strength and a 22.8% decrease in flexural strength. For the polymer-fiber modified concrete, the compressive strength increased by 6%-31%, whereas the flexural strength decreased by 9%-16%. The modified concrete also exhibited significantly improved compression and flexural toughness under VE conditions. Notably, the combination of RDP and PEF yielded the greatest enhancement in mechanical properties, increasing compressive energy absorption capacity over two-fold and flexural energy absorption capacity more than ten-fold compared to the control group. Acoustic emission test results indicate that VE can reduce the damage-warning time by approximately 40%. The RA-AF correlation features show that the proportion of shear cracks increases significantly during the failure stage, which is attributed to intensified fiber-matrix interfacial debonding and the propagation of microcracks in the interfacial transition zone (ITZ). SEM images revealed that vacuum exposure promotes RDP/MEA film formation, creating an interpenetrating network of rigid cement paste and flexible film. This film bonds strongly with hydration products, reducing internal stresses and preventing microcracks. Additionally, PEF enhances post-peak toughness through its three-dimensional network and sliding energy dissipation, while the low fracture elongation and strong matrix adhesion of CF lead to brittle pull-out, thereby reducing concrete toughness.

Conclusions

The main conclusions of this paper are summarized as follows. The compressive and flexural toughness of the control group concrete under VE is significantly reduced, while modification with polymers and fibers can effectively avert this issue. Vacuum exposure enhances the film-forming effect of the polymer, effectively bridging hydration products and forming a high-toughness three-dimensional network structure together with the fibers, thereby inhibiting microcrack propagation. In particular, the combination of RDP and PEF exerts the optimal synergistic toughening effect, allowing the specimens to better retain their post-peak toughness. The synergistic mechanism of "film toughening-sliding energy dissipation" effectively reduces the brittleness of the concrete and improves its performance under vacuum conditions. These findings provide practical references for the optimized design of the new ultra-high-speed vacuum pipeline maglev transportation system as well as materials for deep space engineering.

Key words

concrete / vacuum exposure / polymer / fiber / acoustic emission

引用本文

龙朝飞, 龙广成, 胡正勇, 唐卓, 张玉庭, 封杰, 杜航宇, 彭磊, 蒋定. 真空暴露对聚合物—纤维改性混凝土力学性能的影响. 硅酸盐学报, 2026 , 54 (1) : 243 -257 . DOI: 10.14062/j.issn.0454-5648.20250466

Zhaofei LONG, Guangcheng LONG, Zhengyong HU, Zhuo TANG, Yuting ZHANG, Jie FENG, Hangyu DU, Lei PENG, Ding JIANG. Effect of Vacuum Exposure on Mechanical Properties of Polymer-Fiber Modified Concrete[J]. Journal of the Chinese Ceramic Society, 2026 , 54 (1) : 243 -257 . DOI: 10.14062/j.issn.0454-5648.20250466

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非金属材料创新中心创新基金(24TDA-1)

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2026年第54卷第1期

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文章信息

doi: 10.14062/j.issn.0454-5648.20250466

接收时间：2025-06-16
首发时间：2026-10-27
出版时间：2026-01-20

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出版历史

收稿日期：2025-06-16
修回日期：2025-07-18

基金

非金属材料创新中心创新基金(24TDA-1)

作者信息

^1．中南大学土木工程学院，长沙 410075

^2．中铁六局集团丰桥桥梁有限公司，北京 100070

通讯作者:

龙广成（1973—），男，博士，教授。

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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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