| 王来贵*,陈强,杨建林,刘向峰,刘囝,赵月.高温后水泥砂浆试件抗压性能与变形场演化实验研究[J].实验力学,2018,33(2):307~317 |
| 高温后水泥砂浆试件抗压性能与变形场演化实验研究 |
| Experimental study of compressive behavior and deformation field evolution of cement mortar sample subjected to elevated temperature |
| 投稿时间：2016-11-16 修订日期：2016-03-03 |
| DOI：10.7520/1001-4888-16-247 |
| 中文关键词: 高温 水泥砂浆试件 数字散斑 变形破坏 标准差统计 |
| 英文关键词:high temperature cement mortar sample digital speckle deformation and failure standard deviation statistics |
| 基金项目:国家自然科学基金(51474121、 51404136)资助 |
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| 摘要点击次数: 764 |
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| 中文摘要: |
| 为研究不同温度作用后水泥砂浆试件的抗压性能及变形破坏规律，对不同温度作用后的试件进行单轴压缩实验，同时采用数字散斑相关方法(DSCM)观测试件局部变形，利用标准差统计分析应变场的变化规律。结果表明：(1)在200℃~800℃温度作用后，高龄期的试件更易发生破坏，试件单轴抗压强度的降低主要是由于水化反应形成的骨架结构在高温作用后发生分解；(2)20℃、200℃和400℃作用后的水泥砂浆试件具有明显的脆性特征，相对而言，600℃和800℃作用后的试件塑性特征明显；(3)局部应变场演化过程分为四个阶段：应变均匀分布阶段、应变成核阶段、应变局部化阶段和破坏阶段；(4)利用标准差统计应变场表征试件变形的不均匀程度，与试件整体应力-应变曲线对比，在接近峰值应力时，应变场标准差急剧增大，表明试件即将发生破坏。上述结果可为预测高温作用后水泥基材料的变形破坏提供参考。 |
| 英文摘要: |
| In order to study the compression behavior and deformation failure pattern of cement mortar sample subjected to different high temperatures, uniaxial compression experiment was carried out. In experiment, digital speckle correlation method (DSCM) was adopted to observe sample's local deformation; the evolution of strain field was analyzed by standard deviation statistics. Experimental results show that (1) At the temperatures of 200℃ to 800℃, cement mortar samples with high curing age are more prone to failure, the reduction of cement mortar sample uniaxial compressive strength is mainly due to the decomposition of skeleton structure formed by hydration reaction after high temperature action; (2) Cement mortar samples have obvious brittle feature when temperature is 20℃、200℃ and 400℃ respectively, in contrast, plastic characteristics of cement mortar sample are obvious when temperature is 600℃ and 800℃ respectively; (3) Evolution process of local strain field can be divided into four stages: strain uniform distribution stage, strain nucleation stage, strain localization stage and failure stage; (4) Standard deviation statistics is used to characterize the uneven degree of sample deformation. Compared with sample's overall stress-strain curve, the standard deviation of strain field increases sharply, when stress is approaching peak value, which indicates that the sample is close to damage. Above results can provide a reference for predicting the deformation and failure of cement-based materials after high temperature action. |
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