FRP-ECC复合约束混凝土圆柱反复受压力学性能

惠迎新; 王文炜; 朱忠锋

doi:10.13801/j.cnki.fhclxb.20220516.004

FRP-ECC复合约束混凝土圆柱反复受压力学性能

doi: 10.13801/j.cnki.fhclxb.20220516.004

惠迎新^{1, 4},
王文炜²,
朱忠锋^3, ,

1.
宁夏大学　土木与水利工程学院，银川 750021
2.
东南大学　交通学院，南京 211189
3.
深圳大学　土木与交通工程学院，深圳 518060
4.
宁夏交通建设股份有限公司，银川 750004

基金项目: 国家自然科学基金(52108230；51878156)；宁夏自治区重点研发计划项目(2020 BFG02005)

详细信息

通讯作者:
朱忠锋，博士，副研究员，研究方向为纤维混凝土及FRP复合材料在桥梁结构中的研究与应用　E-mail: zhongfeng.zhu@szu.edu.cn

中图分类号: TB528；TU599
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出版历程
- 收稿日期: 2022-02-11
- 修回日期: 2022-04-13
- 录用日期: 2022-04-29
- 网络出版日期: 2022-05-16
- 刊出日期: 2022-11-01

Cyclic compression behavior of FRP-ECC confined concrete cylinder

1.
School of Civil and Hydraulic Engineering, Ningxia University, Yinchuan 750021, China
2.
School of Transportation, Southeast University, Nanjing 211189, China
3.
College of Civil and Transportation Engineering, Shenzhen University, Shenzhen 518060, China
4.
Ningxia Communications Construction CO., LTD., Yinchuan 750004, China

Funds: National Natural Science Foundation of China (52108230；51878156); Key Research & Development Plan Project of Ningxia Hui Autonomous Region of China (2020BFG02005)

摘要

摘要: 考虑核心柱混凝土强度等级、碳纤维增强树脂复合材料(FRP)网格层数、反复荷载形式等因素，对FRP网格与工程水泥基复合材料(ECC)复合增强混凝土圆柱进行了轴向受压试验，研究约束圆柱的承载力和变形能力。试验结果表明，约束柱的破坏形态表现为FRP柔性网格断裂；随着网格层数的增加，约束柱的极限荷载和变形性能分别提高2%~35%和77%~145%；随着核心混凝土强度等级的提高，复合约束柱的极限承载力提高幅度降低。此外，根据试验结果并结合FRP约束混凝土的应力-应变关系模型，本文针对FRP-ECC复合约束圆柱在反复荷载作用下提出了相应的强度模型和应力-应变关系包络线模型。分析结果表明，模型所得轴向应力-轴向应变及轴向应力-环向应变关系曲线均与试验值吻合良好。
- 反复荷载 /
- FRP网格 /
- ECC /
- 约束圆柱 /
- 应力-应变模型 /
- 混凝土圆柱
Abstract: Considering the strength grade of core concrete, reinforcement layer of fiber-reinforced polymer (FRP) textile, the axial compressive tests of concrete cylinders strengthened with FRP textile and engineered cementitious composites (ECC) were carried out to study the bearing capacity and deformation performance of the FRP-ECC confined cylinder. The test results show that the failure mode of most strengthened cylinders is the rupture of embedded FRP flexible textile. With the increase of reinforcement FRP textile layers, the strengthened columns’ ultimate bearing capacity and deformation performance are improved by 2%-35% and 77%-145%, respectively. With the increase of the strength grade of the core concrete, the increase range of the ultimate bearing capacity is gradually reduced. In addition, according to the test results and the stress-strain model of FRP confined concrete, the corresponding strength model and envelope stress-strain models of FRP-ECC confined cylinder are given. The analysis results show that the stress-strain curves predicted by these models match well with test results.
- cyclic loading /
- FRP textile /
- ECC /
- confined cylinder /
- stress-strain model /
- concrete cylinder

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图 1 荷载形式

Figure 1. Load schemes

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图 2 CFRP-ECC轴拉应力-应变曲线^[28]

Figure 2. Stress-strain curves of CFRP-ECC^[28]

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图 3 圆柱增强过程：(a) 模具；(b) 预处理；(c) 缠网格；(d) 增强柱

Figure 3. Strengthening of cylinder: (a) Mould; (b) Pretreatment; (c) Wrapping textile; (d) Strengthening cylinder

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图 4 试验测试装置

LVDT—Linear variable differential transformer

Figure 4. Test setup

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图 5 CFRP-ECC复合约束混凝土圆柱破坏形态：(a) 无约束柱；(b) 2层增强；(c) 3层增强；(d) 主裂缝

Figure 5. Failure mode of CFRP-ECC confined column: (a) Unconfined column; (b) 2 layers strengthening; (c) 3 layers strengthening; (d) Main crack

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图 6 CFRP-ECC复合约束混凝土圆柱荷载-位移曲线

Figure 6. Load-deformation curves of CFRP-ECC confined column

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图 7 CFRP-ECC复合约束混凝土圆柱应力-应变曲线

ε_c—Axial compressive strain; ε_l—Lateral strain

Figure 7. Stress-strain curves of CFRP-ECC confined column

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图 8 CFRP-ECC复合约束混凝土圆柱应力-应变关系

A, B, C, D—Reference points; E₁, E₂, E₃—Slope at each stage of the curve; m—Curvature parameter; f_cc' and ε_cc—Ultimate strength and strain; f₀—Intercept stress

Figure 8. Stress-strain relationship of CFRP-ECC confined column

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图 9 CFRP-ECC复合约束混凝土圆柱极限应力/应变分析

Figure 9. Analysis of CFRP-ECC confined cylinders’ ultimate stress/strain

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图 10 CFRP-ECC复合约束混凝土圆柱截距应力及模型-试验对比

Figure 10. Intercept stress of CFRP-ECC confined cylinders and model-test comparsion

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图 11 CFRP-ECC复合约束混凝土圆柱峰值后曲线斜率发展规律及模型-试验对比

Figure 11. Relationship of post-peak curve slope of CFRP-ECC confined cylinders and model-test comparsion

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图 12 CFRP-ECC复合约束混凝土圆柱轴向-环向应变关系

Figure 12. Axial-lateral strain relationship of CFRP-ECC confined cylinders

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图 13 CFRP-ECC复合约束混凝土圆柱再加载应力与初始卸载点应力关系

Figure 13. Initial unload stress vs reload stress of CFRP-ECC confined cylinders

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图 14 CFRP-ECC复合约束混凝土圆柱残余应变与初始卸载点应变关系

Figure 14. Initial unload strain vs residual plastic strain of CFRP-ECC confined cylinders

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图 15 CFRP-ECC复合约束混凝土圆柱应力-应变关系对比

Figure 15. Comparison of stress-strain curves of CFRP-ECC confined cylinders

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表 1 工程水泥基复合材料(ECC)配合比

Table 1. Mix proportion of engineered cementitous composites (ECC) kg/m³

Water	Cement	Sand	Water reducer	Fly ash	Fiber	Silica fume
330	351	317	4.5	1052	26	40

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表 2 试验方案

Table 2. Experimental program

Sample	Number in each group	CFRP layer	Thickness of ECC/mm
2CFRP-ECC-C35(A)	3	2	10
3CFRP-ECC-C35(A)	3	3
1CFRP-ECC-C35(B)	3	1
2CFRP-ECC-C35(B)	3	2
3CFRP-ECC-C35(B)	3	3
1CFRP-ECC-C55(B)	3	1
2CFRP-ECC-C55(B)	3	2
3CFRP-ECC-C55(B)	3	3
Notes：For the sample, the first number represents the layer of CFRP textile; CFRP—Carbon fiber reinforced polymer; CFRP-ECC—Strengthening CFRP-ECC composite layer; C35, C55—Strength grade of core concrete; A, B—Loading scheme.

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表 3 素混凝土强度

Table 3. Compressive strength of plain concrete

ID	$ \varepsilon _{{\text{co}}}^{{'}} $/%	$ f_{{\text{co}}}^{{'}} $/MPa	Average		150 mm cube strength
ID	$ \varepsilon _{{\text{co}}}^{{'}} $/%	$ f_{{\text{co}}}^{{'}} $/MPa	$ \varepsilon _{{\text{co}}}^{{'}} $/%	$f_{ {\text{co} } }^{{'} }$/MPa	150 mm cube strength
C35	0.35	25.75	0.32	28.74	36.38
	0.28	31.44
	0.32	29.03
C55	0.24	48.41	0.24	46.67	59.08
	0.28	44.61
	0.21	46.99
Notes：$ \varepsilon _{{\text{co}}}^{{'}} $, $ f_{{\text{co}}}^{{'}} $—Peak strain and stress of plain concrete; Conversion ratio between cylinder and cube is 0.79^[43].

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表 4 CFRP-ECC复合约束混凝土圆柱试验数据

Table 4. Test results of CFRP-ECC confined columns

Sample	$ \varepsilon _{\text{l}} $/%	$ \varepsilon _{{\rm{cc}}} /\%$	$f_{ {\rm{cc}}}^{{'}}/\rm MPa$	Average			${ {\varepsilon _{ {\text{cc} } } } }/{ {\varepsilon _{ {\text{co} } }^{ {'} } } }$	${ {f_{ {\text{cc} } }^{ {'} } } }/{ {f_{ {\text{co} } }^{ {'} } } }$
Sample	$ \varepsilon _{\text{l}} $/%	$ \varepsilon _{{\rm{cc}}} /\%$	$f_{ {\rm{cc}}}^{{'}}/\rm MPa$	$ \varepsilon _{\text{l}} $ /%	$ \varepsilon _{{\text{cc}}} $/%	$ f_{ {\text{cc} }} ^{'}$/MPa
1CFRP-ECC-C35(B)-1	1.06	0.70	33.1	1.07	0.56	31.1	1.77	1.08
1CFRP-ECC-C35(B)-2	1.01	0.39	29.1
1CFRP-ECC-C35(B)-3	1.13	0.60	31.0
2CFRP-ECC-C35(B)-1	0.96	0.71	30.1	1.06	0.67	31.2	2.12	1.09
2CFRP-ECC-C35(B)-2	1.16	0.63	32.3	1.06	0.67	31.2	2.12	1.09
3CFRP-ECC-C35(B)-1	0.78	0.73	37.2	0.86	0.76	37.7	2.40	1.31
3CFRP-ECC-C35(B)-2	0.95	0.60	36.4
3CFRP-ECC-C35(B)-3	0.85	0.95	39.5
2CFRP-ECC-C55(B)-1	–	0.25	47.8	0.97	0.46	49.1	1.89	1.05
2CFRP-ECC-C55(B)-2	1.15	0.67	49.8
2CFRP-ECC-C55(B)-3	0.78	0.46	49.6
3CFRP-ECC-C55(B)-1	0.88	0.51	47.3	0.88	0.51	47.5	2.10	1.02
3CFRP-ECC-C55(B)-2	–	0.29	45.4
3CFRP-ECC-C55(B)-3	0.88	0.51	49.8
2CFRP-ECC-C35(A)-1	0.80	0.70	34.6	1.01	0.58	34.1	1.83	1.19
2CFRP-ECC-C35(A)-2	1.09	0.56	34.1
2CFRP-ECC-C35(A)-3	1.15	0.48	33.8
3CFRP-ECC-C35(A)-1	0.71	0.79	38.1	1.01	0.78	38.7	2.45	1.35
3CFRP-ECC-C35(A)-2	1.30	0.76	39.3	1.01	0.78	38.7	2.45	1.35
Notes: $ \varepsilon _{{\rm{cc}}}$ and $f_{ {\rm{cc}}}^{{'}}$—Ultimate axial strain and ultimate strength of confined cylinders.

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表 5 CFRP-ECC复合约束混凝土圆柱模型和试验结果对比

Table 5. Comparison of model and test results of CFRP-ECC confined cylinders

Sample	Test		Prediction		Prediction/Test
Sample	$ \varepsilon _{{\text{cc}}}^{} $ /%	$f_{ {\text{cc} } }^{{'} }$ /MPa	$ \varepsilon _{{\text{cc}}}^{} $ /%	$f_{ {\text{cc} } }^{{'} }$ /MPa	$ {\varepsilon _{{\text{cc}}}} $	$f_{ {\text{cc} } }^{{'} }$
1CFRP-ECC-C35(B)	0.56	31.06	0.53	31.72	0.94	1.02
2CFRP-ECC-C35(B)	0.67	31.19	0.65	34.84	0.97	1.12
3CFRP-ECC-C35(B)	0.76	37.68	0.78	38.33	1.03	1.02
2CFRP-ECC-C55(B)	0.46	49.07	0.45	48.98	0.98	1.00
3CFRP-ECC-C55(B)	0.51	47.50	0.53	51.13	1.04	1.08
2CFRP-ECC-C35(A)	0.58	34.13	0.65	34.84	1.13	1.02
3CFRP-ECC-C35(A)	0.78	38.70	0.78	38.33	1.01	0.99
Mean					1.01	1.04
SD					0.06	0.03
CV					0.055	0.034
Notes: Mean—Average value; SD—Standard deviation; CV—Coefficient of variation.

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