| 杨柯红,肖东,陈爽,王婷,唐丽,黄锐.火灾高温对轻骨料混凝土蠕变行为及微观结构的影响[J].火灾科学,2026,35(1):59-67. |
| 火灾高温对轻骨料混凝土蠕变行为及微观结构的影响 |
| The influence of high temperature in fire on the creep behavior and microstructure of lightweight aggregate concrete |
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| DOI：10.3969/j.issn.1004-5309.2026.01.07 |
| 基金项目:四川省轨道交通线路智慧运维工程研究中心课题(2024GD-Y13);四川省科技计划重点研发项目(2022-ZY00-00005-CG) |
| 作者 | 单位 | | 杨柯红 | 1. 郑州工商学院工学院, 郑州, 451400 | | 肖东 | 2. 轨道交通线路智慧运维四川省工程研究中心, 成都, 610218 | | 陈爽 | 2. 轨道交通线路智慧运维四川省工程研究中心, 成都, 610218 | | 王婷 | 2. 轨道交通线路智慧运维四川省工程研究中心, 成都, 610218 | | 唐丽** | 3. 成都生产力促进中心, 成都, 610041 | | 黄锐 | 4. 四川省公路规划勘察设计研究院有限公司, 成都, 610041 |
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| 中文关键词: 火灾环境 轻骨料混凝土 蠕变行为 微观机理 耐火性 |
| 英文关键词:Fire environment Lightweight aggregate concrete Creep behavior Microscopic mechanism Fire resistance |
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| 中文摘要: |
| 为研究火灾高温下粉煤灰陶粒骨料混凝土蠕变响应及微观结构形貌,对经不同温度(20 ℃、200 ℃、400 ℃、600 ℃和800 ℃)处理后的陶粒骨料混凝土试件进行了分级单轴压缩蠕变、电镜扫描(SEM)及X衍射(XRD)试验。结果表明:粉煤灰陶粒骨料混凝土分级压缩蠕变曲线呈典型的台阶式增长趋势,蠕变依次经历了减速蠕变和等速蠕变;温度与应力水平对蠕变的影响存在耦合协同效应;蠕变比随应力水平的变化曲线形态呈“勾形”,与20 ℃相比,200 ℃、400 ℃、600 ℃和800 ℃下的临界蠕变破坏应力分别降低了4.3%、8.7%、12.3%及25.1%,即随着温度升高,试件越易发生蠕变失稳破坏;采用推荐的Burgers蠕变模型对粉煤灰陶粒骨料混凝土两阶段蠕变特性进行表征,拟合度较高,相关系数R2≥0.98;高温导致混凝土各组分发生物理化学变化,导致热裂纹萌生、扩展,结构孔隙率增加、致密性下降以及界面过渡区性质劣化,而粉煤灰陶粒的化学稳定性和结构完整性均强于天然骨料,因而抗高温蠕变性更加优异。 |
| 英文摘要: |
| To study the creep response and microstructure morphology of fly ash ceramic aggregate concrete under high temperature in fire, graded uniaxial compression creep, electron microscopy (SEM) and X-ray diffraction (XRD) tests were conducted on ceramic aggregate concrete specimens treated at different temperatures (20 ℃, 200 ℃, 400 ℃, 600 ℃ and 800 ℃). The results indicate that the graded compression creep curve of fly ash ceramic aggregate concrete shows a typical step-like growth trend, with creep experiencing deceleration creep and constant velocity creep in sequence; There is a coupling synergistic effect between temperature and stress level on creep; The curve shape of creep ratio with stress level shows a "hook" shape. Compared with 20 ℃, the critical creep failure stress at 200 ℃, 400 ℃, 600 ℃, and 800 ℃ is reduced by 4.3%, 8.7%, 12.3%, and 25.1%, respectively. That is to say, as the temperature increases, the specimen is more prone to creep instability failure; The recommended Burgers creep model was used to characterize the two-stage creep characteristics of fly ash aggregate concrete, with a high degree of fit and a correlation coefficient R2≥0.98; High temperature causes physical and chemical changes in various components of concrete, leading to the initiation and propagation of hot cracks, an increase in structural porosity, a decrease in density, and a deterioration of interfacial transition zone properties. However, the chemical stability and structural integrity of fly ash ceramic particles are superior to those of natural aggregates, resulting in superior high-temperature creep resistance. |
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