湿热酸雨环境对CFRP-混凝土界面剪切粘结性能影响

易富; 杨纪; 马泽宇; 殷雨时

doi:10.13801/j.cnki.fhclxb.20221107.002

湿热酸雨环境对CFRP-混凝土界面剪切粘结性能影响

doi: 10.13801/j.cnki.fhclxb.20221107.002

易富¹,
杨纪²,
马泽宇¹,
殷雨时^3, ,

1.
辽宁工程技术大学　建筑与交通学院，阜新 123000
2.
辽宁工程技术大学　土木工程学院，阜新 123000
3.
同济大学　土木工程学院，上海 200092

基金项目: 国家自然科学基金(51978501；51774163)

详细信息

通讯作者:
殷雨时，博士，副教授，研究方向为混凝土耐久性和FRP加固理论　E-mail：yinys@alumni.tongji.edu.cn

中图分类号: TB332
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出版历程
- 收稿日期: 2022-09-20
- 修回日期: 2022-10-14
- 录用日期: 2022-10-30
- 网络出版日期: 2022-11-07
- 刊出日期: 2023-08-15

Effect of hot and humid acid rain environment on shear bond properties of CFRP-concrete interface

YI Fu¹,
YANG Ji²,
MA Zeyu¹,
YIN Yushi^{3
, ,}

1.
School of Architecture and Transportation, Liaoning University of Engineering and Technology, Fuxin 123000, China
2.
School of Civil Engineering, Liaoning University of Engineering and Technology, Fuxin 123000, China
3.
School of Civil Engineering, Tongji University, Shanghai 200092, China

Funds: National Natural Science Foundation of China (51978501; 51774163)

摘要

摘要: 为研究湿热酸雨环境对碳纤维增强树脂复合材料(CFRP)-混凝土界面剪切粘结性能影响，设计并制作了45个CFRP-混凝土单剪试件，采用机械高温干湿循环和人工配制pH为1.5的酸雨溶液来模拟湿热酸雨环境，通过开展CFRP-混凝土切向剪切试验，分析了混凝土强度和腐蚀次数对界面破坏模式、剥离承载力、极限位移、荷载-位移曲线和粘结区间应变分布的影响，建立了基于湿热酸雨影响系数的界面本构关系模型，并提出了湿热酸雨环境腐蚀程度划分参考方法。研究结果表明：随着混凝土强度提高，界面粘结性能增强，界面剥离位置逐步向胶层处变化；随着腐蚀次数增长，界面粘结性能呈现先升高后降低的变化趋势，3种强度混凝土对应界面剥离荷载和极限位移分别比未受到腐蚀的试件提升3.04%、3.50%、5.78%和0.50%、0.49%、0.95%，酸雨中SO₄ ²⁻离子侵入混凝土表层生成膨胀性物质CaSO₄·2H₂O，会导致腐蚀前期界面粘结性能暂时增强；切向剪切试验中荷载-位移曲线呈现上升、震荡、加强和下降4个阶段；粘结区间上应力传递方向为从加载端传递至自由端；文中提出基于湿热酸雨影响系数的界面本构关系模型，与现有试验数据吻合度较好，且精度较高，偏于安全。相关研究成果可为高湿高热酸雨地区CFRP加固工程提供理论支撑和设计指导。
- 湿热酸雨环境 /
- CFRP /
- 混凝土 /
- 界面 /
- 剪切粘结性能 /
- 耐久性
Abstract: In order to study the influence of hot and humid acid rain environment on the shear bond performance of carbon fiber reinforced polymer (CFRP)-concrete interface, 45 CFRP concrete single shear specimens were designed and manufactured. The hot and humid environment was simulated by mechanical high temperature dry and wet cycles and manually configured acid rain solution with pH 1.5. Through CFRP concrete shear tests, the effects of concrete strength and corrosion times on the interface failure mode, peel bearing capacity, ultimate displacement, load displacement curve and strain distribution in the bonding zone were discussed, an interfacial constitutive model based on the influence coefficient of hot and humid acid rain was established, and the reference method for the division of corrosion degree in hot and humid acid rain environment was proposed. The results show that with the increase of concrete strength, the interface bonding performance is enhanced, and the interface peeling position gradually changes to the adhesive layer. With the increase of corrosion times, the interfacial bonding performance presents a trend of increasing first and then decreasing. The corresponding interfacial peel bearing load and ultimate displacement of the three strength concretes are 3.04%, 3.50%, 5.78% and 0.50%, 0.49%, 0.95% higher than those of the uncorroded specimens, respectively. SO₄ ^2– ions in acid rain invade the concrete surface to generate expansive material CaSO₄·2H₂O, which will temporarily enhance the interfacial bonding performance in the early stage of corrosion. In the tangential shear test, the load displacement curve presents four stages: Rising, concussion, strengthening and falling. The direction of stress transfer in the bonding zone is from the loading end to the free end. The interfacial constitutive model of the influence coefficient of hot and humid acid rain proposed in this paper is in good agreement with the existing test data, with high accuracy and safety. The related research results can provide theoretical support and design guidance for CFRP reinforcement project in high humidity and high heat acid rain area.
- hot and humid acid rain environment /
- CFRP /
- concrete /
- interface /
- shear bonding property /
- durability

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图 1 混凝土试件尺寸

Figure 1. Size figure of concrete

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图 2 CFRP粘贴区域图示

x—Horizontal distance from the free end

Figure 2. Bond area position graphic of CFRP

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图 3 CFRP布上应变片布置图示

Figure 3. Strain gauges position graphic pasted on CFRP

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图 4 CFRP-混凝土试件升温曲线

Figure 4. Increasement temperature curve of CFRP-concrete specimens

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图 5 CFRP-混凝土试件酸雨侵蚀模拟环境

Figure 5. Acid rain corrosion environment of CFRP-concrete specimens

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图 6 CFRP-混凝土切向剪切试验系统

Figure 6. Tangential shear test system of CFRP-concrete specimens

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图 7 CFRP-混凝土试件破坏模式

Figure 7. Failure modes of CFRP-concrete specimens

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图 8 不同腐蚀循环次数下CFRP-混凝土试件界面破坏形态

Figure 8. Interfacial failure patterns under different corrosion times of CFRP-concrete specimens

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图 9 不同腐蚀次数下CFRP-混凝土试件荷载-位移曲线

Figure 9. Load-displacement curves of CFRP-concrete specimen under different corrosion times

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图 10 不同腐蚀次数下CFRP应变分布

Figure 10. Strain distribution of CFRP under different corrosion time

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图 11 基于湿热酸雨劣化因子界面参数回归

Figure 11. Regression of interfacial parameters based on humid and hot acid rain deterioration factor

${\tau _{{\rm{max}}}} $—Interfacial bonding strength between FRP and concrete; $\alpha $—Statistical regression coefficient of experimental data; ${\beta _{\rm{L}}} $, ${\beta _{\rm{w}}} $—Interfacial FRP length influence coefficient and width influence coefficient; ${f_{\rm{t}}} $—Tensile strength of concrete; ${P_{\rm{u}}} $—Interfacial peeling bearing capacity; b_f—Width of FRP sheet; E_f—Elastic modulus of FRP sheet; ${\gamma _1} $—Based parameter ${\tau _{\max }} $ deterioration factor of humid hot acid rain; ${s_{{\rm{f}}{\rm{.}}}} $—Based parameter ${s_{{\rm{f}}{\rm{.}}}} $ deterioration factor of humid hot acid rain

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图 12 参量($ {\tau }_{\text{max}}，{s}_{\text{f.}} $)和($ \alpha ,{\beta _{\text{w}}},{\beta _{\text{L}}},{f_{\text{t}}} $)之间的关系

R²—Correlation coefficient

Figure 12. Relationships between parameters ($ {\tau _{{\text{max}}}} $, $ {{{s}}_{\text{f.}}} $) and ($ \alpha ,{\beta _{\text{w}}},{\beta _{\text{L}}},{f_{\text{t}}} $)

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表 1 混凝土配合比

Table 1. Mixture ratio of concrete kg/m³

Specimen	Cement	Fine sand	Coarse aggregate	Water	Fly ash	Water reducer	W/C
C30	298	824	1007	167	53	5.27	0.48
C40	335	737	1018	164	53	9.50	0.42
C50	353	725	1044	144	53	7.20	0.35
Note: W/C—Water to cement ratio.

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表 2 材料物理参数指标

Table 2. Material physical parameters

Material		$ {f_{\text{c}}} $/MPa	$ {f_{\text{t}}} $/MPa	$ {E_{\text{f}}} $/MPa	$ {{{t}}_{\text{f}}} $/mm	$ {{{m}}_{\text{f}}} $/(g·m⁻²)
Specimen	C30	35.0	5.3	—	—	—
	C40	46.0	6.4	—	—	—
	C50	57.5	7.4	—	—	—
CFRP	—	—	3400	2.3×10⁵	0.167	300
Epoxy resin	—	—	38	2.4×10³	—	—
Notes: $ {f_{\text{c}}} $—Compressive strength of concrete cube; $ {f_{\text{t}}} $—Tensile strength of concrete, carbon fiber reinforced polymer (CFRP) and epoxy resin, the tensile strength of concrete is not measured in the test, so it is converted by the formula$ {f_{\text{t}}} = \dfrac{{{{\left( {{f_{\text{c}}}} \right)}^{2/3}}}}{2} $; $ {E_{\text{f}}} $—Elastic modulus of fiber cloth and epoxy resin; $ {{{t}}_{\text{f}}} $—Single layer thickness of fiber cloth; $ {{{m}}_{\text{f}}} $—Mass per unit area of fiber cloth.

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表 3 酸雨溶液配制

Table 3. Acid rain solution mixturement 40 L

pH value	98% sulfuric acid content/(g·L⁻¹)	65% nitric acid content/(g·L⁻¹)	Mole ratio H₂SO₄: HNO₃
1.5	63.24	7.12	9:1

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表 4 酸雨侵蚀试验工况

Table 4. Test conditions of acid rain corrosion

Number	Specimen/block	Corrosion cycle time	Corrosive environment
f_i-0	3×3	0	Non corrosive
f_i-10	3×3	10	High temperature and humidity acid rain environment
f_i-20	3×3	20
f_i-30	3×3	30
f_i-40	3×3	40
i=30, 40, 50	Total: 45	–
Notes: In the expression f_i-a, i represents three concrete strength grades, C30, C40 and C50 respectively; a represents the number of corrosion cycles. For example, f₃₀-10 represents the C30 CFRP-concrete specimen subjected to 10 corrosion cycles.

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表 5 CFRP-混凝土切向剪切试验数值

Table 5. Interfacial shear test data between CFRP and concrete

Strength grade	Peel load/kN	Ultimate displacement/mm
C30	6.89	2.02
C40	7.15	2.05
C50	7.78	2.10

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表 6 CFRP-混凝土试件剥离荷载与极限位移

Table 6. Peel load and ultimate displacement of CFRP-concrete specimen

Strength grade	Corrosion time	P_u/kN				S_f/mm
Strength grade	Corrosion time	1	2	3	Average	1	2	3	Average
C30	0	6.89	6.86	6.92	6.89	1.88	1.92	2.26	2.02
	10	6.54	6.99	7.77	7.10	1.95	1.99	2.15	2.03
	20	6.19	6.35	6.45	6.33	1.45	1.62	1.37	1.48
	30	4.03	3.88	4.15	4.02	1.43	1.41	1.45	1.43
	40	4.03	3.89	4.05	3.99	1.25	1.30	1.35	1.30
C40	0	6.95	7.07	7.43	7.15	1.91	2.07	2.17	2.05
	10	6.56	6.72	8.93	7.40	2.43	1.62	2.14	2.06
	20	6.65	6.98	5.66	6.43	0.81	2.24	1.75	1.60
	30	3.09	5.49	—	4.29	1.28	1.70	—	1.49
	40	4.24	4.39	4.32	4.32	—	1.37	1.35	1.36
C50	0	7.05	7.77	8.52	7.78	2.10	2.24	1.97	2.10
	10	8.20	8.45	8.04	8.23	2.10	2.33	1.93	2.12
	20	6.99	7.13	6.55	6.89	1.95	1.80	1.89	1.88
	30	4.99	4.77	4.55	4.77	1.71	1.75	1.88	1.78
	40	4.10	4.70	4.85	4.75	1.60	1.70	1.80	1.70
Notes: "—" in the table indicates that no valid data is collected due to test error, human operation and other reasons; P_u—Peel load; S_f—Ultimate displacement.

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表 7 腐蚀环境对应混凝土表面腐蚀程度

Table 7. Corrosion degree of concrete surface corresponding to corrosion environment

Ⅰ category	Ⅱ category	Ⅲ category	Ⅳ category
Severe corrosion	Harsh corrosion	Moderate corrosion	Slight corrosion

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表 8 本文模型与现有模型精确度比对

Table 8. Accuracy comparison between new and existed models

Data source	Proposed model	Lu^[10]	Neubauer & Rostasy^[33]	Monti et al^[34]
Data source	Test/Predict	Test/Predict	Test/Predict	Test/Predict
Wu et al^[28]	4.29	6.98	13.14	12.27
Takeo et al^[29]	2.23	3.50	5.55	5.68
Tan^[30]	1.82	2.91	4.56	4.52
Ren^[31]	1.66	2.68	3.76	3.78
Ueda et al^[32]	2.67	4.12	6.48	6.47

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