海洋环境下BFRP筋与混凝土黏结性能及基本锚固长度计算方法研究
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摘要
本文研究了海水浸泡环境对BFRP(Basalt Fiber Reinforced Polymer)筋与混凝土黏结性能的影响,测试了不同温度(25℃,40℃和55℃)下极限黏结强度随浸泡龄期的变化规律。结合加速腐蚀理论,并考虑环境温度和湿度的影响,对极限黏结强度随服役年限的变化规律进行了预测。参考既有文献中的97个BFRP筋黏结强度试验数据,推导了BFRP筋短期黏结强度计算公式。依据本文理论预测得出的50年设计使用年限下的黏结强度损伤因子,推导了不同环境湿度类别下的锚固长度计算公式。试验结果表明:25℃,40℃和55℃海水浸泡60天后,极限黏结强度分别降低了5.8%、9.1%和13.0%。预测结果表明,在南海年平均温度下,服役50年后,室内环境、一般室外环境和潮湿海洋环境类别下的黏结强度损伤因子分别为0.19、0.32和0.51。本文提出的基本锚固长度设计方法可为相关规范条款的制定提供依据。
In this paper,the effects of seawater immersion on the bond performance between BFRP( Basalt Fiber Reinforced Polymer) bar and concrete were investigated. The variations of ultimate bond strengths with immersion time at various temperatures( 25℃,40℃ and 55℃) were tested. In combination with the theory of accelerated corrosion,the degradation law of ultimate bond strength with service year considering the influence of environment temperature and humidity was predicted. In addition,the formula for the short-term bond strength between BFRP bar and concrete was derived from the data of 97 BFRP bar bond tests collected from literatures. With the bond damage factors for a design service life of 50 years predicted in this study,the calculation formulas for the basic anchorage length of BFRP bar with concrete at different environmental humidity categories were obtained. Test results showed that the ultimate bond strength was reduced by 5. 8%,9. 1% and 13. 0% after being immersed in 25℃,40℃ and 55℃ seawater for 60 days,respectively. The predicted bond damage factors for indoor environment,normal outdoor environment and humid ocean environment were 0. 19,0. 32 and 0. 51,respectively,after servicing 50 years at the annual average temperature of the South China Sea area. The proposed design method for the basic anchorage length of BFRP bar is reasonable and could be adopted by relevant specifications.
In this paper,the effects of seawater immersion on the bond performance between BFRP( Basalt Fiber Reinforced Polymer) bar and concrete were investigated. The variations of ultimate bond strengths with immersion time at various temperatures( 25℃,40℃ and 55℃) were tested. In combination with the theory of accelerated corrosion,the degradation law of ultimate bond strength with service year considering the influence of environment temperature and humidity was predicted. In addition,the formula for the short-term bond strength between BFRP bar and concrete was derived from the data of 97 BFRP bar bond tests collected from literatures. With the bond damage factors for a design service life of 50 years predicted in this study,the calculation formulas for the basic anchorage length of BFRP bar with concrete at different environmental humidity categories were obtained. Test results showed that the ultimate bond strength was reduced by 5. 8%,9. 1% and 13. 0% after being immersed in 25℃,40℃ and 55℃ seawater for 60 days,respectively. The predicted bond damage factors for indoor environment,normal outdoor environment and humid ocean environment were 0. 19,0. 32 and 0. 51,respectively,after servicing 50 years at the annual average temperature of the South China Sea area. The proposed design method for the basic anchorage length of BFRP bar is reasonable and could be adopted by relevant specifications.
引文
[1]Robert M,Benmokrane B.Combined effects of saline solution and moist concrete on long-term durability of GFRP reinforcing bars[J].Construction&Building Materials,2013,38(1):274-284
[2]Dejke V.Durability of FRP reinforcement in concrete—literature review and experiments[D].Goteborg:Chalmers University of Technology,2001
[3]Dejke V,Tepfers R.Durability and service life time prediction of GFRP for concrete reinforcement[C].FRPPCS-5,Thomas Telford,London,2001
[4]Robert M,Benmokrane B.Effect of aging on bond of GFRP bars embedded in concrete[J].Cement and Concrete Composites,2010,32(6):461-467
[5]Alves J,El-Ragaby A,El-Salakawy E.Durability of GFRP bars’bond to concrete under different loading and environmental conditions[J].Journal of Composites for Construction,2011,15(3):249-262
[6]Zaidi A,Masmoudi R.Bond performance of basalt fiberreinforced polymer bars to concrete[J].American Society of Civil Engineers,2014
[7]Adhikari S.Mechanical properties and flexural applications of basalt fiber reinforced polymer(BFRP)bars[D].Akron:University of Akron,2009
[8]Ovitigala T.Structural behavior of concrete beams reinforced with basalt fiber reinforced polymer(BFRP)bars[D].Chicago:University of Illinois,2012
[9]El Safty A,Benmokrane B,Rizkalla S,et al.Degradation assessment of internal continuous fiber reinforcement in concrete environment[M].University of North Florida,2014
[10]吴芳.玄武岩纤维筋与混凝土黏结性能试验研究[D].大连:大连理工大学,2009(Wu Fang.The experimental research on bond behavior between BFRP rebars and the concrete[D].Dalian:Dalian University of Technology,2009(in Chinese))
[11]单炜,张绍逸.BFRP筋与混凝土的黏结一滑移本构关系[J].建筑科学与工程学报,2013,30(2):15-20(Shan Wei,Zhang Shaoyi.Bond-slip constitutive relation between BFRP bar and concrete[J].Journal of Architecture and Civil Engineering,2013,30(2):15-20(in Chinese))
[12]周俊龙,李炳宏,江世永,等.玄武岩纤维增强塑料筋混凝土黏结性能的梁式试验研究[J].中国塑料,2011,25(4):83-88(Zhou Junlong,Li Binghong,Jiang Shiyong,et al.Experimental study on bond behavior of BFRP bars embedded in concrete by beam test[J].China Plastics,2011,25(4):83-88(in Chinese))
[13]Refai A E,Abed F,Altalmas A,et al.Bond durability of basalt fiber-reinforced polymer bars embedded in concrete under direct pullout conditions[J].Journal of Composites for Construction,2014,DOI:10.1061/(ASCE)CC.1943-5614
[14]ASTM D1141—98 Standard practice for the preparation of substitute ocean water[S].West Conshohocken:ASTM International,2008
[15]Bank L,Russell Gentry T,Thompson B,et al.A model specification for composites for civil engineering structures[J].Construction and Building Materials,2003,17(6):405-437
[16]Caceres A,Jamond R M,Hoffard T A,et al.Accelerated testing of fiber reinforced polymer matrix composites-test plan[J].NFESC Special Publication SP-2091-SHR,2000
[17]Wu G,Dong Z Q,Wang X,et al.Prediction of long-term performance and durability of BFRP bars under the combined effect of sustained load and corrosive solutions[J].Journal of Composites for Construction,2014,19(3)
[18]Huang J,Aboutaha R.Environmental reduction factors for GFRP bars used as concrete reinforcement:new scientific approach[J].Journal of Composites for Construction,2010,14(5):479-486
[19]GB 50608—2010纤维增强复合材料建设工程应用技术规范[S].北京:中国计划出版社,2010(GB50608—2010 Technical code for infrastructure application of FRPcomposites[S].Beijing:China planning press,2010(in Chinese))
[20]ACI440.1R—06 Guide for the design and construction of structural concrete reinforced with FRP bars[S].Farmington Hills:American Concrete Institute,2006
[21]Wambeke B W,Shield C K.Development length of glass fiber reinforced polymer bars in concrete[J].ACI Structural Journal,2006,103(1):11-17
[2]Dejke V.Durability of FRP reinforcement in concrete—literature review and experiments[D].Goteborg:Chalmers University of Technology,2001
[3]Dejke V,Tepfers R.Durability and service life time prediction of GFRP for concrete reinforcement[C].FRPPCS-5,Thomas Telford,London,2001
[4]Robert M,Benmokrane B.Effect of aging on bond of GFRP bars embedded in concrete[J].Cement and Concrete Composites,2010,32(6):461-467
[5]Alves J,El-Ragaby A,El-Salakawy E.Durability of GFRP bars’bond to concrete under different loading and environmental conditions[J].Journal of Composites for Construction,2011,15(3):249-262
[6]Zaidi A,Masmoudi R.Bond performance of basalt fiberreinforced polymer bars to concrete[J].American Society of Civil Engineers,2014
[7]Adhikari S.Mechanical properties and flexural applications of basalt fiber reinforced polymer(BFRP)bars[D].Akron:University of Akron,2009
[8]Ovitigala T.Structural behavior of concrete beams reinforced with basalt fiber reinforced polymer(BFRP)bars[D].Chicago:University of Illinois,2012
[9]El Safty A,Benmokrane B,Rizkalla S,et al.Degradation assessment of internal continuous fiber reinforcement in concrete environment[M].University of North Florida,2014
[10]吴芳.玄武岩纤维筋与混凝土黏结性能试验研究[D].大连:大连理工大学,2009(Wu Fang.The experimental research on bond behavior between BFRP rebars and the concrete[D].Dalian:Dalian University of Technology,2009(in Chinese))
[11]单炜,张绍逸.BFRP筋与混凝土的黏结一滑移本构关系[J].建筑科学与工程学报,2013,30(2):15-20(Shan Wei,Zhang Shaoyi.Bond-slip constitutive relation between BFRP bar and concrete[J].Journal of Architecture and Civil Engineering,2013,30(2):15-20(in Chinese))
[12]周俊龙,李炳宏,江世永,等.玄武岩纤维增强塑料筋混凝土黏结性能的梁式试验研究[J].中国塑料,2011,25(4):83-88(Zhou Junlong,Li Binghong,Jiang Shiyong,et al.Experimental study on bond behavior of BFRP bars embedded in concrete by beam test[J].China Plastics,2011,25(4):83-88(in Chinese))
[13]Refai A E,Abed F,Altalmas A,et al.Bond durability of basalt fiber-reinforced polymer bars embedded in concrete under direct pullout conditions[J].Journal of Composites for Construction,2014,DOI:10.1061/(ASCE)CC.1943-5614
[14]ASTM D1141—98 Standard practice for the preparation of substitute ocean water[S].West Conshohocken:ASTM International,2008
[15]Bank L,Russell Gentry T,Thompson B,et al.A model specification for composites for civil engineering structures[J].Construction and Building Materials,2003,17(6):405-437
[16]Caceres A,Jamond R M,Hoffard T A,et al.Accelerated testing of fiber reinforced polymer matrix composites-test plan[J].NFESC Special Publication SP-2091-SHR,2000
[17]Wu G,Dong Z Q,Wang X,et al.Prediction of long-term performance and durability of BFRP bars under the combined effect of sustained load and corrosive solutions[J].Journal of Composites for Construction,2014,19(3)
[18]Huang J,Aboutaha R.Environmental reduction factors for GFRP bars used as concrete reinforcement:new scientific approach[J].Journal of Composites for Construction,2010,14(5):479-486
[19]GB 50608—2010纤维增强复合材料建设工程应用技术规范[S].北京:中国计划出版社,2010(GB50608—2010 Technical code for infrastructure application of FRPcomposites[S].Beijing:China planning press,2010(in Chinese))
[20]ACI440.1R—06 Guide for the design and construction of structural concrete reinforced with FRP bars[S].Farmington Hills:American Concrete Institute,2006
[21]Wambeke B W,Shield C K.Development length of glass fiber reinforced polymer bars in concrete[J].ACI Structural Journal,2006,103(1):11-17