Time-dependent behaviors of CFRP cable-UHPC interface under elevated temperature

Zhengwen Jiang, Jiayang Zou, Zhi Fang, Yawei Fang, Quanhao Li and Zhiwei Wang

Abstract

To investigate time-dependent behaviors of ultra-high performance concrete (UHPC)-filled anchorage system for Carbon fiber-reinforced polymer (CFRP) cable under elevated temperature, high-temperature creep and relaxation tests were conducted on CFRP cable-UHPC interface. The variation laws of creep slippage at loading end and relaxation stress of CFRP cable-UHPC interface with different initial pullout load and effective bond length under different target temperature were identified. High-temperature pullout tests were conducted on specimens after high-temperature creep or relaxation stage, for obtaining its residual mechanical performance. The influence of thermos-mechanical coupling effect on bearing capacity for CFRP cable-UHPC interface was quantified. Finally, practical models for determining high-temperature creep and relaxation laws of CFRP cable-UHPC interface and calibrating relationship between creep and relaxation behaviors under high temperature at steady stage for CFRP cable-UHPC interface were developed. The obtained results demonstrated that both creep slippage time and stress loss-time curves of CFRP cable-UHPC interface under target temperature from 100 to 210°C display deformation characteristics of two-stage including transient and steady stages. The growth rate of the creep slippage of CFRP cable-UHPC interface increased with treatment temperature or initial pullout load, while the slippage growth rate of CFRP cable-UHPC interface at transient creep stage increased with the decreasing bond length. The changing rule of relaxation stress of CFRP cable-UHPC interface is similar with that of creep slippage. Slip failure is the dominant failure mode of CFRP cable UHPC interface after experience of high-temperature creep or relaxation stage. Due to the thermo-mechanical coupling effects in high-temperature creep and relaxation tests, the Bearing capacities for CFRP cable-UHPC interface decreased 0.21~12.37% and 0.83~10.65%, respectively.

Key Words

bond-type anchorage; CFRP cable-UHPC interface; high-temperature creep and relaxation behaviors; residual mechanical 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 Diagno4sis of Engineering Structures of Hunan Province, College of Civil Engineering, Hunan University, Changsha, 410082, China Jiayang Zou:Key Laboratory for Damage Diagno4sis of Engineering Structures 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 Yawei Fang:1)Key Laboratory for Wind and Bridge Engineering of Hunan Province, College of Civil Engineering, Hunan University, Changsha, 410082, China 2)Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Hong Kong Quanhao Li:Key Laboratory for Damage Diagno4sis of Engineering Structures 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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