| 摘要: |
| 研究了不同温度下超高性能混凝土（UHPC）的受弯力学行为，并利用吸能效率、声发射能量释放率和振铃计数表征了UHPC脆性失效的演变机制，构建了3种UHPC受弯本构模型.结果表明：当温度为-170 ℃时，UHPC的初裂抗弯强度和峰值抗弯强度分别从20 ℃的10.6、20.9 MPa增至21.1、42.5 MPa；在20~-170 ℃范围内，UHPC的脆性随温度降低先减小后增大，并在-80 ℃时达到最小值、-170 ℃时达到最大值；相较于过镇海教授和吴泽媚博士的本构模型，线性-非线性本构模型的预测精度最高、数据离散性最低. |
| 关键词: 超高性能混凝土 抗弯强度 超低温 脆性 本构关系 |
| DOI：10.3969/j.issn.1007-9629.2024.01.004 |
| 分类号:TU528.01 |
| 基金项目:国家自然科学基金资助项目（U22B2076， 51878480， 52078369，52108241）；2021年产业技术基础公共服务平台项目（2021-H029-1-1）；上海市优秀学术带头人计划资助项目（22XD1403300）；中央高校基本科研业务费专项资金资助项目 |
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| Flexural Behaviour and Constitutive Correlation of UHPC at Cryogenic Temperatures |
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AI Jinhua1,2, HE Bei1,2, ZHANG Yi1,2, ZHANG Hongen1,2, JIANG Zhengwu1,2
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1.Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education， Tongji University， Shanghai 201804， China;2.School of Materials Science and Engineering， Tongji University， Shanghai 201804， China
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| Abstract: |
| The flexural mechanical behavior of ultra-high performance concrete （UHPC） at different temperatures was studied. The brittle failure evolution mechanism of UHPC was characterized with energy absorption efficiency， acoustic emission energy release rate and ring-down count. Three flexural constitutive models of UHPC were established. The results show that when the temperaure is -170 ℃， the first-peak and maximum flexural strength of UHPC increase from 10.6， 20.9 MPa at 20 ℃ to 21.1， 42.5 MPa， respectively. Within the range of 20--170 ℃， with the decrease of temperature， the brittleness of UHPC firstly increases and then decreases， showing the minimum brittleness at -80 ℃ and the maximum brittleness at -170 ℃， respectively. Compared to the constitutive models of Prof. Guo Zhenhai and Dr.Wu Zemei， the linear-nonlinear constitutive model has the highest prediction accuracy and the lowest data variability. |
| Key words: ultra-high performance concrete（UHPC） flexural strength cryogenic temperature brittleness constitutive correlation |
