首页|超低温-高温交变环境下UHPC的拉伸行为及其声发射损伤时序演化

超低温-高温交变环境下UHPC的拉伸行为及其声发射损伤时序演化

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  • 国家科技期刊平台
  • NETL
  • NSTL
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为揭示极端温度环境下超高性能混凝土(UHPC)的性能演变及其劣化机制,明确了UHPC在-170～200℃范围内的拉伸行为,并基于声发射(AE)技术原位监测了UHPC的温变损伤与裂缝演化规律.结果表明:在超低温-高温交变环境下,直纤维与端钩纤维增强UHPC的拉伸破坏均呈现应变硬化特征;在单次温变循环内,UHPC的力学性能呈现起伏波动,其中超低温下最高,高温下最低;多次温变循环后,UHPC力学性能则相应降低;UHPC破坏产生的AE信号蕴含着丰富的损伤特征参数,其AE峰频形态在超低温和高温下会发生分化,而其余环境下则呈集中式单峰分布;除超低温外,其余环境下的UHPC开裂均以拉伸裂缝为主,且端钩纤维增强UHPC的拉伸裂缝数量低于直纤维增强UHPC;随着温变循环次数的增加,UHPC的拉伸裂缝数量随之减少.
Tensile behavior and its temporal evolution of acoustic emission damage of UHPC under alternating cryogenic and elevated environments
To reveal the performance evolution and degradation mechanism of ultra-high performance concrete(UHPC)under extreme temperature environments,the tensile behavior of UHPC in the range of-170 ℃ to 200 ℃ was investigated,and the temperature-variation damage and crack evolution of UHPC were in-situ monitored by acoustic emission(AE)technology.The results indicate that under the alternating cryogenic and elevated environments,the tensile failure of UHPC with straight and hooked-end steel fibers exhibits strain-hardening characteristics.In first temperature-variation cycle,the mechanical properties of UHPC show fluctuations,with the highest at cryogenic temperatures and the lowest at elevated temperatures.After multiple cycling,the mechanical properties of UHPC decrease accordingly.The AE signal generated by UHPC damage contains abundant failure characteristic parameters,and its AE peak frequency morphology differentiates at cryogenic and elevated temperatures,while that exhibits a centralized single peak distribution in other environments.Except for cryogenic temperatures,UHPC cracking in other environments is mainly tensile cracks,and the number of tensile cracks in the hooked-end fiber group is lower than that in the straight fiber group.As the cycling increasing,the number of tensile cracks in UHPC decreases.

ultra-high performance concretecryogenic temperatureelevated temperaturetensile behavioracoustic emission parametertemporal evolution

何倍、张红恩、赵铭睿、朱新平、任强、张翼、蒋正武

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同济大学材料科学与工程学院,上海 201804

同济大学先进土木工程材料教育部重点实验室,上海 201804

中海石油气电集团有限责任公司,北京 100028

超高性能混凝土 超低温 高温 拉伸行为 声发射参数 时序演化

国家自然科学基金项目国家自然科学基金项目全国建材行业重大科技攻关"揭榜挂帅"项目上海市优秀学术带头人计划

U22B2076520783692023JBGS01-122XD1403300

2024

10.14006/j.jzjgxb.2023.0529

建筑结构学报
中国建筑学会

建筑结构学报

CSTPCD北大核心
影响因子：1.546
ISSN：1000-6869
年,卷(期)：2024.45(9)