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| 高温后钢筋与混凝土粘结性能试验与损伤机理分析 |
| Experimental study on bond behavior and damage mechanism analysis of reinforcing steel to concrete interface after elevated temperature |
| Received:December 23, 2016 Revised:March 05, 2017 |
| DOI：10.7520/1001-4888-16-283 |
| 中文关键词: 高温后 钢筋混凝土 粘结性能 统计分析 微观损伤机理 |
| 英文关键词:after high temperature reinforced concrete bond behavior statistical analysis damage mechanisms |
| 基金项目:国家自然科学基金(51378200)资助 |
| Author Name | Affiliation | | ZHOU Zi-jian | China Ministry of Education Key Laboratory of Building Safety and Energy Efficiency, College of Civil Engineering, Hunan University, Changsha 410082, Hunan, China | | HUO Jing-si* | 1.China Ministry of Education Key Laboratory of Building Safety and Energy Efficiency, College of Civil Engineering, Hunan University, Changsha 410082, Hunan, China
2.College of Civil Engineering, Huaqiao University, Xiamen 361021, Fujian, China | | JIN Bao | 1.China Ministry of Education Key Laboratory of Building Safety and Energy Efficiency, College of Civil Engineering, Hunan University, Changsha 410082, Hunan, China
3.Wuhuan Engineering Co., Ltd., Wuhan 430070, Hubei, China |
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| 中文摘要: |
| 钢筋与混凝土的高温粘结性能是研究钢筋混凝土结构抗火性能的基础，通过制作15个立方体混凝土试块和11个中心拉拔粘结锚固试件，分别进行200~800℃高温后抗压试验和拔出试验，研究了经历不同温度后混凝土抗压强度和与钢筋粘结性能的变异情况。对历年来高温后混凝土粘结试验数据进行了统计分析，并通过有限元拟合对试验温度场进行了修正，总结了高温后钢筋与混凝土粘结性能的退化规律和影响因素，同时比对了高温后粘结强度与混凝土抗压强度、弹性模量和抗拉强度的相关性。基于现有高温后混凝土材料微观试验结果，从微观结构层面解释了宏观粘结性能变化规律，并分析了高温后粘结性能微观损伤机理。结果表明：高温后钢筋与混凝土的粘结强度随着温度升高呈现下降的趋势，且与高温后混凝土抗拉强度衰减规律相近。同时，高温后混凝土残余粘结强度与混凝土高温微观结构密切相关，与水泥凝胶体HCP孔隙率之间具有良好的相关性。 |
| 英文摘要: |
| Bond behavior of reinforcing steel to concrete interface at elevated temperature is the basis of studying fire-resistance of RC structures. Fifteen cubic concrete specimens and eleven central pull-out specimens were made, then compression tests and pullout tests were conducted to experimentally study the variation of concrete compressive strength and bond behavior after exposed to 200~800℃ temperature. Experimental data of bond behavior of reinforcing steel to concrete after exposure to temperatures conducted over the years were statistically analyzed. The experimental temperature field was corrected based on finite element analysis. Degradation and influencing factors of bonding behavior between reinforcing bar and concrete after high temperatures were summarized. At the same time, the correlation between bond strength and compressive strength, elastic modulus and tensile strength of concrete after elevated temperatures was compared and analyzed. Based on existing microstructure tests on plain concrete after elevated temperatures, the change of macroscopic bond behavior was explained from microscopic point of view. Microscopic damage mechanism of bond behavior after elevated temperature heating was analyzed. Analysis results show that the residual bond strength decreases with the increase of heating temperature, which is similar to the degradation of tensile strength of heated concrete. At the same time, the residual bond strength of heated concrete is closely related with its microstructure at elevated temperature, and also related with the porosity of hardened cement paste (HCP). |
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