高温环境对混凝土内GFRP筋拉伸性能退化影响

doi:10.19936/j.cnki.2096-8000.20250228.002

摘要/Abstract

摘要： 对埋置于混凝土内的玻璃纤维增强复合材料(GFRP)筋进行高温后拉伸试验,分析了高温下混凝土试件内外温度变化、筋材外观变化,重点探讨了高温后混凝土内GFRP筋拉伸性能退化规律及其抗拉强度保留系数的预测方法。试验与分析结果表明:混凝土内GFRP筋存在明显温度滞后现象,炉内升温约2 h后,混凝土内GFRP筋才能达到环境温度,混凝土保护层降低了内部筋材在高温后的松散程度;300~350 ℃的工况温度下,混凝土保护层对GFRP筋的抗拉强度保护作用较明显。工况温度达到400 ℃后,GFRP筋的拉伸性能迅速下降,混凝土保护层的隔温保护作用逐渐减弱至消失;300 ℃工况下,恒温时长对混凝土内GFRP筋抗拉强度影响显著,对其弹性模量影响较小;采用Boltzmann函数可以有效预测混凝土内GFRP筋在高温后的抗拉强度保留系数。相关研究可为GFRP筋在混凝土结构中的耐火设计提供参考。

关键词: 玻璃纤维增强复合材料(GFRP), 高温环境, 混凝土, 拉伸性能, 预测模型

Abstract: Tensile tests of glass fiber reinforced polymer (GFRP) bars embedded in concrete were carried out after high temperature. The variations of temperature difference between the inner and external locations of concrete specimen and the appearance changes of GFRP bars were analyzed. The degradation of tensile properties of GFRP bars was discussed and the prediction method of the tensile strength retention coefficient of GFRP bars in concrete after high temperature was proposed. The test and analysis results show that there is an obvious temperature lag phenomenon of GFRP bars placed in concrete. The temperature at the surface of GFRP bar can reach the operating temperature after about 2 h of heating in the furnace. The cover concrete can reduce the degree of looseness of the internal bars after high temperature and its protective effect on the tensile strength retention of GFRP bars is more obvious under the operating temperature of 300~350 ℃. When the operating temperature reaches 400 ℃, the tensile properties of GFRP bars decrease rapidly and the protective effect of cover concrete on the thermal insulation gradually weakens to disappear. Under the condition of 300 ℃, the constant temperature time has significant influence on the tensile strength of GFRP bars in concrete, but has little influence on its elastic modulus. Boltzmann’s function can be adopted to effectively predict the tensile strength retention of GFRP bars in concrete after high temperatures. The related research can provide references for the fire-resistant design of GFRP bars in concrete structures.

Key words: glass fiber reinforced composite (GFRP), high temperature environment, concrete, tensile property, prediction model

中图分类号:

TB332

陆春华, 李朝晖, 漆仲浩, 朱学武, 徐奕帆. 高温环境对混凝土内GFRP筋拉伸性能退化影响[J]. 复合材料科学与工程, 2025, 0(2): 12-19.

LU Chunhua, LI Zhaohui, QI Zhonghao, ZHU Xuewu, XU Yifan. Effect of high temperature environment on degradation of tensile properties of GFRP bars in concrete[J]. COMPOSITES SCIENCE AND ENGINEERING, 2025, 0(2): 12-19.

参考文献

[1] 赵羽习. 钢筋锈蚀引起混凝土结构锈裂综述[J]. 东南大学学报(自然科学版), 2013, 43(5): 1122-1134.
[2] 罗大明, 牛荻涛. 基于钢筋锈蚀的混凝土结构耐久性评定[J]. 工业建筑, 2022, 52(10): 1-8, 70.
[3] 陈泰谷, 胡守旺, 罗远彬, 等. 基于试验数据库的 FRP 筋增强混凝土梁抗剪承载力可靠度分析[J]. 复合材料科学与工程, 2022(2): 5-10.
[4] 都凡, 欧阳利军, 陆洲导, 等. 高温(火灾)下 FRP筋混凝土构件力学性能研究进展[J]. 玻璃钢/复合材料, 2016(7): 79-85.
[5] 王晓璐, 査晓雄. 高温下GFRP筋力学性能的试验研究[J]. 华南理工大学学报(自然科学版), 2011, 39(9): 75-81.
[6] WANG Y C, WONG P M H, KODUR V. An experimental study of the mechanical properties of fiber reinforced polymer (FRP) and steel reinforcing bars at elevated temperatures[J]. Composite Structures, 2007, 80: 131-140.
[7] ASHRAFI H, BAZLI M, NAJAFABADI E P, et al. The effect of mechanical and thermal properties of FRP bars on their tensile performance under elevated temperatures[J]. Construction and Building Materials, 2017, 157: 1001-1010.
[8] LU C H, QI Z H, GE H, et al. Predicting the mechanical properties of E-glass fiber-reinforced polymer bars after exposure to elevated temperature[J]. Construction and Building Materials, 2023, 379: 131238.
[9] NAJAFABADI E P, OSKOUEI A V, KHANEGHAHI M H, et al. The tensile performance of FRP bars embedded in concrete under elevated temperatures[J]. Construction and Building Materials, 2019, 211: 1138-1152.
[10] KODUR V K R, BISBY L A. Evaluation of fire endurance of concrete slabs reinforced with fiber-reinforced polymer bars[J]. Journal of Structural Engineering, 2005, 131(1): 34-43.
[11] NIGRO E, CEFARELLI G, BILOTTA A, et al. Fire resistance of concrete slabs reinforced with FRP bars. Part Ⅱ: experimental results and numerical simulations on the thermal field[J]. Composites Part B: Engineering, 2011, 42(6): 1751-1763.
[12] 查晓雄, 王晓璐, 谢先义. GFRP筋混凝土梁耐火性能的试验研究[J]. 防灾减灾工程学报, 2012, 32(1): 50-55.
[13] ALSAYED S, AL-SALLOUM Y, ALMUSALLAMET T, et al. Performance of glass fiber reinforced polymer bars under elevated temperatures[J]. Composites Part B: Engineering, 2012, 43: 2265-2271.
[14] 张凯. 火灾高温下及高温后结构中 FRP 筋残余力学性能研究[D]. 南京: 东南大学, 2018.
[15] AYDIN F, AKYÜREK M, ARSLAN Ş, et al. Effects of concrete cover thickness and concrete strength on temperature transfer in high temperature exposed FRP reinforced concrete[J]. Revista de la Construcción, 2023, 22(1): 242-258.
[16] JIA D G, GAO W Y, DUAN D X, et al. Full-range behavior of FRP-to-concrete bonded joints subjected to combined effects of loading and temperature variation[J]. Engineering Fracture Mechanics, 2021, 254: 107928.
[17] International Organization for Standardization. Fire-resistance tests-elements of building construction: ISO 834-1: 1999[S].
[18] 徐可, 陆春华, 宣广宇, 等. 温度老化对GFRP/BFRP 筋残余弯曲性能的影响[J]. 材料导报, 2021, 35(4): 4053-4060.
[19] HAMAD R J A, JOHARI M A M, HADDAD R H. Mechanical properties and bond characteristics of different fiber reinforced polymer rebars at elevated temperatures[J]. Construction and Building Materials, 2017, 142: 521-535.
[20] ZHOU C H, PAN J J, ZHANG Z H, et al. Comparative study on the tensile mechanical behavior of GFRP bars under and after high temperature exposure[J]. Case Studies in Construction Materials, 2022, 16: e00905.
[21] SPAGNUOLO S, MEDA A, RINALDI Z, et al. Residual behaviour of glass FRP bars subjected to high temperatures[J]. Composite Structures, 2018, 203: 886-893.
[22] ÖZKAL F M, POLAT M, YAĞAN M, et al. Mechanical properties and bond strength degradation of GFRP and steel rebars at elevated temperatures[J]. Construction and Building Materials, 2018, 184: 45-57.
[23] MOURITZ A P, GIBSON A G. Fire properties of polymer composite materials[M]. Berlin: Springer Science & Business Media, 2007.
[24] NIGRO E, CEFARELLI G, BILOTTA A, et al. Guidelines for flexural resistance of FRP reinforced concrete slabs and beams in fire[J]. Composites Part B: Engineering, 2014, 58: 103-112.
[25] 何亚元, 李利巍, 骆海贺, 等. Boltzmann函数拟合法确定高强钢韧脆转变温度[J]. 物理测试, 2020, 38(1): 7-9.