| 摘要: |
| 采用40mm×40mm×160mm棱柱体试件，研究了高温后大掺量粉煤灰应变硬化水泥基复合材料（HVFA SHCC）的单轴压缩力学性能，探讨了不同目标温度（100、200、400、600、800℃）和不同冷却方式（自然冷却、浸水冷却）条件下HVFA SHCC试件抗压强度、弹性模量、压缩韧性、破坏模式及质量的变化.采用扫描电子显微镜（SEM）对试件的微观结构进行分析，获得了高温后HVFA SHCC单轴压缩性能的劣化机理.结果表明：当温度低于200℃时,温度对试件力学性能及质量损失的影响较小；400～800℃时，试件内部结构变得疏松，残余力学性能劣化严重，尤其是800℃时，试件的抗压强度仅为常温状态的399%，弹性模量为常温状态的323%，压缩韧性指数为常温状态的590%，质量损失率达155%；浸水冷却试件的残余力学性能得到了一定程度的提高.同时，基于试验结果，建立了高温后HVFA SHCC的单轴压缩本构方程. |
| 关键词: 大掺量粉煤灰应变硬化水泥基复合材料 高温 冷却方式 残余力学性能 微观结构 本构关系 |
| DOI：103969/j.issn.1007 9629202101004 |
| 分类号: |
| 基金项目:中原千人计划中原科技创新领军人才项目（ZYQR201912029）；国家自然科学基金资助项目(51708510)；河南省科技攻关（国际合作项目）(182102410045)；教育部长江学者和创新团队发展计划项目(IRT16R67) |
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| Uniaxial Compressive Behavior and Constitutive Relationship of HVFA SHCC after Exposure to High Temperature |
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ZHAO Jun1, NIU Miaoxin2, ZHOU Jiajia1, WANG Zhi1
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1.School of Mechanics and Safety Engineering, Zhengzhou University, Zhengzhou 450001, China;2.School of Civil Engineering, Zhengzhou University, Zhengzhou 450001, China
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| Abstract: |
| Investigations on the residual uniaxial compressive behaviors of strain hardening cementitious composites with high volume of fly ash(HVFA SHCC) subjected to elevated temperatures were carried out. Specimens with dimension of 40mm×40mm×160mm were exposed to different temperatures（100，200，400，600，800℃）. Residual compressive strength, stress strain curves, compressive toughness, elastic modulus and failure mode were determined after two cooling methods(natural cooling and water cooling). Scanning electron microscope(SEM) was used to analyze the degradation mechanism of HVFA SHCC at mesoscale level. Experimental results indicate that the temperature has little effect on the mechanical properties and mass loss of HVFA SHCC when temperature is lower then 200℃. At 400800℃, the internal micro structures of HVFA SHCC specimen become loose and the residual mechanical properties deteriorate seriously. When the temperature is higher than 800℃, the average residual compressive strength, the elastic modulus and the toughness index of the samples is only 399%, 323% and 590% of that at room temperature, respectively. And the mass loss rate is increased to 155%. Meanwhile, the effect of cooling method on residual mechanical properties is significant. The specimens cooled in water exhibit superior residual mechanical performance. Finally, based on the test results, the uniaxial compressive constitutive relationship of HVFA SHCC after high temperature is proposed. |
| Key words: strain hardening cementitious composites with high volume of fly ash（HVFA SHCC） high temperature cooling method residual mechanical property microstructure constitutive relationship |
