Repair of fire-damaged RC square columns with CFRP textile-reinforced ECC matrix
Repair of fire-damaged RC square columns with CFRP textile-reinforced ECC matrix
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DOI：
10.1016/j.engstruct.2023.116530
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发表时间：
2023-10
影响因子：
5.5
通讯作者：
Wangyag Liu;Li-jun Ouyang;W. Gao;Jian Liang;TianYang Wang;Jiang Song;Jian Yang
中科院分区：
文献类型：
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作者：
Wangyag Liu;Li-jun Ouyang;W. Gao;Jian Liang;TianYang Wang;Jiang Song;Jian Yang
纤维增强聚合物（Fiber-reinforced Polymer，FRP）织物增强水泥基复合材料（Textile Reinforced Engineered Cementitious Composite，ECC）基体（简称TRE）是一种新型的复合材料体系，对火灾后受损钢筋混凝土（RC）柱的加固和延寿具有很大的潜力。它结合了FRP织物的轻质和高强度以及ECC材料的超高延展性的优点。然而，有一个缺乏研究使用TRE系统，以加强火灾损坏的钢筋混凝土柱。对TRE加固火灾后钢筋混凝土方柱的轴心受压性能进行了试验研究。共制备了13个样本，并在轴向压缩条件下进行了测试。测试变量包括用于产生RC柱的初始预损伤的火灾暴露时间（2 h或3 h）、水泥基质的类型（ECC或砂浆）、TRE层的数量（2层或3层）以及混凝土保护层的厚度（20 mm或40 mm）。对试件的破坏模式、承载力、割线刚度、极限位移、荷载-位移曲线以及CFRP织物最外层的环向拉伸应变进行了研究和讨论。加固试件的典型破坏模式为桥接加固夹套主裂纹的纤维粗纱的拉伸断裂。结果表明，TRE体系的使用可以显着提高火灾后钢筋混凝土柱的承载力，割线刚度和极限位移。根据设计参数，负载能力的增强百分比在18%和126%之间变化。
Fiber-reinforced polymer (FRP) textile reinforced engineered cementitious composite (ECC) matrix (TRE for short) is a newly developed composite system with great potential for the strengthening and life extension of damaged reinforced concrete (RC) columns after fire exposure. It combines the advantages of the lightweight and high strength of FRP textile and the ultra-high ductility of ECC material. However, there is a lack of research on the use of the TRE system to strengthen fire-damaged RC columns. This paper presents an experimental study on the axial compressive behavior of fire-damaged square RC columns strengthened with the TRE system. A total of 13 specimens were prepared and tested under axial compression. The test variables included the fire-exposure time (2 h or 3 h) used to produce the initial pre-damage of RC columns, the type of cementitious matrix (ECC or mortar), the number of TRE layers (2 layers or 3 layers), and the thickness of the concrete cover (20 mm or 40 mm). The failure modes, load capacity, secant stiffness, ultimate displacement, load–displacement curves of the specimens and the hoop tensile strains in the outermost layer of the CFRP textiles were investigated and discussed. The typical failure mode of the strengthened specimens was characterized by tensile rupture of the fiber rovings bridging the main crack in the strengthening jacket. The results showed that the use of the TRE system could significantly increase the load capacity, secant stiffness and ultimate displacement of fire-damaged RC columns. Depending on the design parameters, the enhancement percentages in the load capacity varied between 18% and 126%.