Axial compression test was conducted to investigate the effect of confinement on plain concrete cylinders by wrapping polyethylene naphthalate fiber reinforced polymer (PEN FRP) with large rupture strain (LRS) capacity. To draw comparison on the confinement effect by PEN FRP wrapping, the confining effect by basalt FRP (BFRP) wrapping was also investigated. A total of 25 tests was completed. Test variables were two different FRP composites (PEN FRP, BFRP) and number of FRP layers (1, 2, 3 layers of PEN FRP and 2, 4, 6 layers of BFRP) in the main confinement tests (21 tests). In the additional confinement tests, the test variable was overlap length of PEN FRP (four tests). Confinement by BFRP and LRS PEN FRP was both effective as demonstrated by continuously ascending stress–strain relationship of the confined concrete. The PEN FRP wrapped concrete deformed more both axially and laterally to develop strength equivalent to that of the BFRP wrapped concrete. A simplified procedure for rational modelling of stress–strain relationship of the confined concrete was suggested. The suggested procedure is applicable for both BFRP and PEN FRP confined circular concretes on condition that basic confinement test data specific to the FRP composite are provided.

中文翻译：

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玄武岩纤维和PEN纤维增强聚合物复合材料横向约束的小型混凝土圆柱体的受压行为

进行轴向压缩试验以研究通过包裹具有大断裂应变 (LRS) 能力的聚萘二甲酸乙二醇酯纤维增强聚合物 (PEN FRP) 来限制对素混凝土圆柱体的影响。为了比较 PEN FRP 包裹的约束效果，还研究了玄武岩 FRP (BFRP) 包裹的约束效果。总共完成了25个测试。测试变量是两种不同的 FRP 复合材料（PEN FRP、BFRP）和 FRP 层数（1、2、3 层 PEN FRP 和 2、4、6 层 BFRP）在主要限制测试（21 次测试）中。在附加约束测试中，测试变量是 PEN FRP 的重叠长度（四次测试）。BFRP 和 LRS PEN FRP 的约束都是有效的，正如约束混凝土的连续上升的应力-应变关系所证明的那样。PEN FRP 包裹的混凝土轴向和横向变形更大，以达到与 BFRP 包裹的混凝土相当的强度。提出了一种对受限混凝土的应力-应变关系进行合理建模的简化程序。在提供特定于 FRP 复合材料的基本约束测试数据的情况下，建议的程序适用于 BFRP 和 PEN FRP 约束圆形混凝土。