Residual bonding properties of CFRP cable-UHPC interface after thermo-mechanical coupling
Zhengwen Jiang,Xilong Zhao,Hao Chen,Zhi Fang,Quanhao Li,Zhiwei Wang
Abstract
To further investigate mechanical properties of the UHPC-filled anchorage system for CFRP cables after fire, pullout tests were conducted on the CFRP cable-UHPC interface after cooling from elevated temperature exposure, considering initial pullout load ratio R. Effects of treatment temperature Tt, R and effective bond length Le on the residual bond-slip behavior of bonding interface after thermo-mechanical coupling were identified. The recovery laws of residual bonding properties of the bonding interface after thermo-mechanical coupling were also quantified. Finally, practical formulas were proposed to determine the residual average bond strength τu-A and recovery proportions of τu-A and the effective shear stiffness KA for the bonding interface after thermo-mechanical coupling. Results demonstrated that slip failure was the primary failure mode at bonding interfaces in all pullout specimens after thermo-mechanical coupling. τu-A and KA decreased by 31.95~32.57% and 21.68~28.78% as Tt increased from 25°C (ambient temperature) to 210°C (the glass transition temperature of resin matrix), respectively. Compared with specimens without initial pullout load after cooling from elevated temperature exposure, those with R ranging from 0.2 to 0.6 and Le of (5~15)d after exposure to 100°C showed further reductions of 4.35~15.43% in τu-A and 9.78~31.13% in KA. The recovery proportions of τu-A and KA increased with increasing Tt in the range of 25~210°C, and decreased with R varying from 0 to 0.6. Practical formulas proposed in this study can predict τu-A and the recovery laws of bonding properties with good accuracy.
Key Words
CFRP cable-UHPC interface; pullout test after thermo-mechanical coupling; recovery law; residual bonding performance
Address
Zhengwen Jiang — 1)Key Laboratory for Wind and Bridge Engineering of Hunan Province, College of Civil Engineering, Hunan University, Changsha, 410082, China 2) Key Laboratory for Damage Diagnosis of Engineering Structures of Hunan Province, College of Civil Engineering, Hunan University, Changsha, 410082, China
Xilong Zhao — Key Laboratory for Wind and Bridge Engineering of Hunan Province, College of Civil Engineering, Hunan University, Changsha, 410082, China
Hao Chen — Key Laboratory for Wind and Bridge Engineering of Hunan Province, College of Civil Engineering, Hunan University, Changsha, 410082, China
Zhi Fang — Key Laboratory for Wind and Bridge Engineering of Hunan Province, College of Civil Engineering, Hunan University, Changsha, 410082, China
Quanhao Li — Key Laboratory for Wind and Bridge Engineering of Hunan Province, College of Civil Engineering, Hunan University, Changsha, 410082, China
Zhiwei Wang — Zhongfu Carbon Fiber Core Cable Technology Co. Ltd., Jiangsu, Lianyungang, 222069, China
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