| 引用本文: | 余琼,魏晋文,张亮,许雪静,余江滔.带肋钢筋与超高延性水泥基复合材料的黏结性能[J].哈尔滨工业大学学报,2022,54(4):132.DOI:10.11918/202104070 |
| YU Qiong,WEI Jinwen,ZHANG Liang,XU Xuejing,YU Jiangtao.Bond behavior between ribbed steel bar and ultra-high ductile cementitious composite[J].Journal of Harbin Institute of Technology,2022,54(4):132.DOI:10.11918/202104070 |
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| 摘要: |
| 超高延性水泥基复合材料（UHDCC）是新型纤维增强混凝土,受拉时表现出超高的延性和应变硬化能力。为提供UHDCC应用于受力构件的界面黏结理论依据,进行了45个钢筋在UHDCC中锚固的拉拔试验,考察了锚固长度、浇筑方式、保护层厚度、90°弯钩等对黏结性能的影响。试验结果表明:由于纤维约束作用,试件未发生劈裂破坏；UHDCC的浇筑方式显著影响黏结强度,垂直浇筑的黏结强度大于平行浇筑；由于UHDCC的应变硬化现象,试件锚固长度从4d增大到6d时黏结强度有上升趋势,大于6d时中心锚固试件（保护层较厚）锚固长度对黏结强度影响不大,偏心锚固试件（保护层较薄UHDCC材料的约束作用减小）随锚固长度增加黏结强度降低；直锚段钢筋长度为4d时,增设90°弯钩(4d)后,承载力提升幅度可达67%,但随着直锚段长度增加,弯钩对承载力提升幅度减小；绝对锚固长度相等时直锚组试件承载力大于带弯钩的试件,弯钩段锚固并不等价于直锚钢筋,弯钩锚固必须保证直锚段长度。论文分析了带肋钢筋与UHDCC之间的黏结滑移机理,给出了UHDCC直接锚固的黏结强度公式。 |
| 关键词: 超高延性水泥基复合材料（UHDCC） 锚固长度 黏结滑移 弯钩锚固 保护层厚度 |
| DOI：10.11918/202104070 |
| 分类号:TU502 |
| 文献标识码:A |
| 基金项目: |
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| Bond behavior between ribbed steel bar and ultra-high ductile cementitious composite |
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YU Qiong,WEI Jinwen,ZHANG Liang,XU Xuejing,YU Jiangtao
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(College of Civil Engineering, Tongji University, Shanghai 200092, China)
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| Abstract: |
| Ultra-high ductile cementitious composite (UHDCC), a new type of fiber reinforced concrete, exhibits ultra-high ductility and strain hardening ability during stretching. In this study, pull tests were conducted on 45 specimens whose ribbed steel bars were all anchored in UHDCC. The influences of anchorage length, pouring method, protective layer thickness, 90-degree hook, and other parameters on the bonding performance were investigated, and a theoretical basis for the bonding strength of the force-bearing members using UHDCC was provided. Results show that all the specimens did not split due to the restraint of the fiber in the UHDCC. The pouring method of UHDCC had significant impact on the bonding strength, and the bonding strength of the specimen poured vertically was greater than that of the specimen poured horizontally. As the anchorage length of the specimen increased from 4d to 6d, the bonding strength tended to increase due to the strain hardening of UHDCC. When the anchorage length was longer than 6d, the anchorage length of the central anchoring specimen (with a thicker protective layer) had little effect on the bonding strength. However, the bonding strength of the eccentric anchoring specimen (whose restraint of UHDCC to the ribbed steel bar decreased due to the thinner protective layer) decreased with the anchorage length increased. A 90-degree hook with the length of 4d was added at the end of the steel bar when the length of the straight anchor section was 4d, and the ultimate bearing capacity was increased by 67%. However, when the length of the straight anchor section increased, the effect of the 90-degree hook on the ultimate bearing capacity began to decrease. When the absolute anchorage lengths were the same, the bearing capacity of the specimens without hooks was greater than that of the specimens with hooks. For the specimen whose steel bar had a 90-degree hook, the anchorage length must be guaranteed. Based on the test results, the bond-slip mechanism between ribbed steel bar and UHDCC was analyzed, and the equation of bonding strength between UHDCC and ribbed steel bar without 90-degree hook was given. |
| Key words: ultra-high ductile cementitious composite (UHDCC) anchorage length bond slip anchorage with hook protective layer thickness |
