高温后CFRP筋及其粘结式锚固系统的力学性能

方志; 方川; 蒋正文; 王志伟; 李俊宇; 张玉庆

doi:10.13801/j.cnki.fhclxb.20210215.005

高温后CFRP筋及其粘结式锚固系统的力学性能

doi: 10.13801/j.cnki.fhclxb.20210215.005

方志^{1, 2, ,},
方川^1,,
蒋正文^1,,
王志伟^3,,
李俊宇^1,,
张玉庆³

1.
湖南大学　土木工程学院，长沙 410082
2.
湖南大学　风工程与桥梁工程湖南省重点实验室，长沙 410082
3.
中复碳芯电缆科技有限公司，连云港 222069

详细信息

通讯作者:
方志，博士，教授，研究方向为基于高性能材料工程结构的设计理论及工程应用技术　E-mail：fangzhi@hnu.edu.cn

中图分类号: TU502
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- 被引次数: 0
出版历程
- 收稿日期: 2020-12-11
- 录用日期: 2021-01-23
- 网络出版日期: 2021-02-18
- 刊出日期: 2021-12-01

Mechanical properties of CFRP bar and bond-type anchorage system after elevated temperature exposure

FANG Zhi^{1, 2
, ,},
FANG Chuan^1
,,
JIANG Zhengwen^1
,,
WANG Zhiwei^3
,,
LI Junyu^1
,,
ZHANG Yuqing³

1.
College of Civil Engineering, Hunan University, Changsha 410082, China
2.
Key Laboratory for Wind and Bridge Engineering of Hunan Province, Hunan University, Changsha 410082, China
3.
Zhongfu Carbon Fiber Core Cable Technology CO. LTD., Lianyungang 222069, China

摘要

摘要: 为明确高温后碳纤维增强树脂复合材料(Carbon fiber reinforced polymer，CFRP)筋材及其粘结型锚固系统的力学性能，以筋材的处理温度为试验参数，完成了12个筋材试件的轴向拉伸试验；以粘结式锚具的处理温度和粘结长度为试验参数，完成了36个试件的锚固性能试验。结果表明：对于筋材轴向拉伸试件，处理温度为100℃时，筋材静力性能与常温试件相比未发生明显变化，筋材经历200℃和300℃温升作用后，其抗拉强度、弹性模量和极限拉应变较常温试件分别下降了6.4%、8.2%、3.8%和16.6%、18.3%、8.3%；对于锚固性能试验，试件的粘结强度随处理温度和粘结长度的增加而降低，粘结长度一定时，处理温度为200℃与300℃试件的粘结强度较常温试件分别下降了31.5%~36.3%和44.2%~47.4%。建立了适于分析高温后CFRP筋轴向拉伸性能、粘结型锚固系统粘结强度及临界锚固长度的实用计算公式，且具较高精度。
- CFRP筋 /
- 粘结型锚固系统 /
- 温升作用 /
- 轴向拉伸性能 /
- 粘结强度 /
- 临界锚固长度
Abstract: To investigate the mechanical properties of carbon fiber reinforced polymer (CFRP) bar and bond-type anchorage system after different elevated temperature exposures, the axial tensile tests and anchorage perfor-mance tests were conducted on 12 specimens and 36 specimens with different elevated temperatures and bond lengths, respectively. The results demonstrate that the static performance of CFRP bar exposed to elevated temperature of 100℃ degenerates slightly compared with the specimen at room temperature in the axial tensile tests. The tensile strength, elastic modulus and ultimate strain of specimens exposed to the elevated temperature of 200℃ and 300℃ decrease by 6.4%, 8.2%, 3.8% and 16.6%, 18.3%, 8.3%, respectively, compared with the specimen at room temperature. In the anchorage performance tests, the bond strength of the specimens decreases with the increase of elevated temperature and bond length. Compared with the specimen at room temperature, the bond strengths of the specimens exposed to the elevated temperature of 200℃ and 300℃ decrease by 31.5%-36.3% and 44.2%-47.4%, respectively, while the bonding length is fixed. The practical formulas with high accuracy for determining the axial tensile performance of CFRP bars, bond strength and critical anchorage length of the bond-type anchorage system after elevated temperature exposure were developed.
- CFRP bar /
- bond-type anchorage system /
- elevated temperature /
- axial tensile performance /
- bonding strength /
- critical anchorage length

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图 1 碳纤维增强树脂复合材料(CFRP)筋轴向拉伸试件

Figure 1. Axial tensile carbon fiber reinforced polymer (CFRP) bar specimen

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图 2 CFRP筋-活性粉末混凝土(RPC)锚固性能试件

Figure 2. Anchorage performance CFRP bar-reactive powder concrete (RPC) specimen

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图 3 温升装置

Figure 3. Setup of elevated temperature

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图 4 温升历程

Figure 4. Process of elevated temperature

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图 5 CFRP筋及其外观尺寸

Figure 5. Dimensions of CFRP bar

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图 6 轴向拉伸试验加载装置

Figure 6. Loading setup of axial tensile test

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图 7 锚固性能试验加载装置

Figure 7. Loading setup of anchorage performance test

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图 8 CFRP筋轴向拉伸破坏形态

Figure 8. Axial tensile failure modes of CFRP bar

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图 9 CFRP筋轴向拉伸试验的应力-应变曲线

Figure 9. Stress-strain curves of CFRP bar in axial tensile test

f_u—Tensile strength

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图 10 温升作用对CFRP筋材轴拉性能的影响

Figure 10. Effect of elevated temperature on the axial tensile performance of CFRP bar

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图 11 CFRP筋-RPC锚固性能试件破坏形态

Figure 11. Typical failure mode of anchorage performance CFRP bar-RPC specimens

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图 12 CFRP筋-RPC锚固性能试件的荷载-滑移曲线

Figure 12. Force-slip curves of anchorage performance CFRP bar-RPC specimens

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图 13 处理温度与粘结长度对CFRP筋-RPC界面粘结强度的影响

Figure 13. Effect of elevated temperature and bond length on bond strength of interface of CFRP bar and RPC

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图 14 高温后CFRP筋轴拉性能对比

Figure 14. Comparison of axial tensile performance of CFRP bars after elevated temperature exposure

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表 1 CFRP筋外观尺寸及玻璃化转变温度T_g

Table 1. Dimensions and glass transition temperature T_g of CFRP bar

Nominal diameter/mm	Rib width/mm	Rib height/mm	Embossing spacing/mm	T_g/℃
12	9.26	0.27	14.8	211.6

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表 2 RPC配合比及抗压强度

Table 2. Mix proportion and compressive strengths of RPC

Strength grade	Cement	Silica fume	Quartz flour	Quartz sand	Water reducer	Water binder ratio	Measured strength/MPa
RPC150	1	0.25	0.25	1.1	0.02	0.16	158

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表 3 CFRP筋-RPC轴向拉伸试验结果

Table 3. Results of axial tensile test for CFRP bar-RPC

Specimen code	$\overline{ P_{\rm{u}}}$/kN	P_u/kN	f_u/MPa	$ \overline{ f_{\rm{u}}} $/MPa	E/GPa	$ \overline E $/GPa	ε_u/10⁻⁶	$ \overline{\varepsilon _{\rm{u}}} $/10⁻⁶
CFRP-RPC-T25-1	280.8	282.8	2631.1		162.2		15627
CFRP-RPC-T25-2	283.1		2652.6	2649.8	161.8	159.9	15464	15513
CFRP-RPC-T25-3	284.5		2665.7		155.6		15448
CFRP-RPC-T100-1	279.9	279.6	2622.6		162.3		15482
CFRP-RPC-T100-2		278.8	2612.3	2619.8	153.6	157.3	15385	15428
CFRP-RPC-T100-3		280.1	2624.5		156.0		15417
CFRP-RPC-T200-1	260.6	264.7	2441.8		151.7		15084
CFRP-RPC-T200-2	269.2		2522.4	2480.2	146.2	146.8	15012	14925
CFRP-RPC-T200-3	264.3		2476.5		142.5		14679
CFRP-RPC-T300-1	242.7	235.8	2274.1		128.4		14285
CFRP-RPC-T300-2	231.4		2168.2	2209.4	133.3	130.7	14364	14232
CFRP-RPC-T300-3	233.3		2186.0		130.4		14047
Notes: Specimen code indicates the test type and treatment temperature; for example, CFRP-RPC-T25-1 means the first specimen of CFRP-RPC anchorage specimen treated at 25℃ in axial tensile test; P_u—Tensile breaking force; $\overline {{P_{\rm{u}}}} $—Average value; $\overline {{f_{\rm{u}}}} $—Average value; E—Elastic modulus; $\overline E $—Average value; ε_u—Ultimate tensile strain; $\overline {{\varepsilon _{\rm{u}}}} $—Average value.

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表 4 CFRP筋-RPC锚固性能试验结果

Table 4. Results of anchorage performance test for CFRP bar-RPC

Specimen code	T/ ℃	l/ mm	P_u/ kN	${\overline {P_{\rm{u}}} }$/ kN	τ_u/ MPa	s/ mm	Specimen code	T/ ℃	l/ mm	P_u/ kN	${\overline {P_{\rm{u}}}} $/ kN	τ_u/ MPa	s/ mm
CFRP-RPC-T25-L5d-1	25	60	69.3	69.35	30.67	5.42	CFRP-RPC-T200-L5d-1	200	60	41.23	47.53	21.02	5.74
CFRP-RPC-T25-L5d-2			69.45			5.36	CFRP-RPC-T200-L5d-2			48.9			5.68
CFRP-RPC-T25-L5d-3			69.3			5.26	CFRP-RPC-T200-L5d-3			52.45			5.80
CFRP-RPC-T25-L10d-1	25	120	135.3	134.1	29.66	5.52	CFRP-RPC-T200-L10d-1	200	120	85.5	85.46	18.9	5.91
CFRP-RPC-T25-L10d-2			132.9			5.35	CFRP-RPC-T200-L10d-2			81.68			5.98
CFRP-RPC-T25-L10d-3			—			—	CFRP-RPC-T200-L10d-3			89.2			5.93
CFRP-RPC-T25-L15d-1	25	180	192.4	190.47	28.08	—	CFRP-RPC-T200-L15d-1	200	180	118.9	123.57	18.22	—
CFRP-RPC-T25-L15d-2			192.7			—	CFRP-RPC-T200-L15d-2			131.8			—
CFRP-RPC-T25-L15d-3			186.3			—	CFRP-RPC-T200-L15d-3			120			—
CFRP-RPC-T100-L5d-1	100	60	62.37	61.09	27.02	5.14	CFRP-RPC-T300-L5d-1	300	60	35.92	37.42	16.55	5.68
CFRP-RPC-T100-L5d-2			59.35			5.26	CFRP-RPC-T300-L5d-2			41.98			5.36
CFRP-RPC-T100-L5d-3			61.55			5.37	CFRP-RPC-T300-L5d-3			34.35			5.41
CFRP-RPC-T100-L10d-1	100	120	119.5	118.23	26.15	5.85	CFRP-RPC-T300-L10d-1	300	120	66.23	70.12	15.51	5.73
CFRP-RPC-T100-L10d-2			115.5			5.84	CFRP-RPC-T300-L10d-2			74.9			5.75
CFRP-RPC-T100-L10d-3			119.7			6.73	CFRP-RPC-T300-L10d-3			69.23			5.68
CFRP-RPC-T100-L15d-1	100	180	173.6	173	25.51	—	CFRP-RPC-T300-L15d-1	300	180	105.3	100.11	14.76	—
CFRP-RPC-T100-L15d-2			174.3			—	CFRP-RPC-T300-L15d-2			96.93			—
CFRP-RPC-T100-L15d-3			171.1			—	CFRP-RPC-T300-L15d-3			98.11			—
Notes: Specimen code indicates the test type and treatment temperature; for example, CFRP-RPC-T25-L5d-1 means the first specimen of CFRP-RPC anchorage specimen treated at 25℃ with bond length of 5d; T—Treatment temperature; l—Bond length; τ_u—Average bond strength; s—Slip of loading end corresponding to P_u.

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表 5 CFRP筋-RPC试件粘结强度试验值与计算值对比

Table 5. Comparison between measured and predicted bond strength of CFRP bar-RPC specimen

Specimen code	f_cu/MPa	τ_u,t/MPa	τ_u,c/MPa	τ_u,t/τ_u,c
CFRP-RPC-T25-L5d	158	30.67	30.97	1.01
CFRP-RPC-T25-L10d	158	29.66	29.06	0.98
CFRP-RPC-T25-L15d	158	28.08	28.42	1.01
CFRP-RPC-T100-L5d	158	27.02	26.91	1.00
CFRP-RPC-T100-L10d	158	26.15	25.25	0.97
CFRP-RPC-T100-L15d	158	25.51	24.70	0.97
CFRP-RPC-T200-L5d	158	21.02	21.49	1.02
CFRP-RPC-T200-L10d	158	18.9	20.17	1.07
CFRP-RPC-T200-L15d	158	18.22	19.72	1.08
CFRP-RPC-T300-L5d	158	16.55	16.08	0.97
CFRP-RPC-T300-L10d	158	15.51	15.08	0.97
CFRP-RPC-T300-L15d	158	14.76	14.75	1.00
Average				1.00
Variation coefficient				0.04
Notes: f_cu—Cube compressive strength of RPC; τ_u,t, τ_u,c—Experimental and calculated values of interfacial bond strength between CFRP bars and RPC, respectively.

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表 6 CFRP筋-RPC试件临界锚固长度计算值及预测的破坏形态

Table 6. Critical anchorage length determined by formula and predicted failure mode of CFRP bar-RPC specimen

Source of test results	Specimen code	T/℃	Anchorage length/mm	Actua failure mode	Critical anchorage length/mm	Predicted failure mode
Present study	CFRP-RPC-T25	25	360	Fracture	284.4	Fracture
	CFRP-RPC-T100
	CFRP-RPC-T200
	CFRP-RPC-T300
Present study	CFRP-RPC-T25-L15d	25	180	Slip	284.4	Slip
	CFRP-RPC-T100-L15d	100			324.8
	CFRP-RPC-T200-L15d	200			386.5
	CFRP-RPC-T300-L15d	300			462.0
Ref.[17]	AT30	30	160	Fracture	126.3	Fracture
	AT100	100		Fracture	151.1	Fracture
	AT200	200		Slip	221.0	Slip
Notes: Failure modes of tensile failure in CFRP bar and slip failure in CFRP-RPC interface were abbreviated as fracture and slip, respectively.

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