摘要
Abstract
In order to explore the effect of high temperature and strain rate on mechanical properties of CFRP confined concrete,the static and dynamic uniaxial compression tests were carried out on three kinds of CFRP con-fined concrete(plain concrete,high temperature CFRP confined concrete and fiber cloth confined high temperature concrete)at different temperatures(25℃,200℃,400℃,600℃)by Muffle furnace,servo press and Hopkin-son press(SHPB).The effects of high temperature,strain rate and confinement mode on peak stress,dynamic re-inforcement factor(DIF),toughness and energy dissipation density of specimens were analyzed.The results show that:the peak stress decreases 7.25%,19.05%and 34.20%at 200℃,400℃and 600℃under static load,the peak stress decreases 5.57%,14.66%and 29.05%at 200℃,400℃and 600℃under 0.5 MPa impact pres-sure.The peak stress of three kinds of concrete specimens decreases with the increase of temperature,and the peak stress of CFRP high temperature concrete is higher than that of plain concrete.The strain rate growth factor of the high temperature concrete specimens confined by plain concrete and carbon fiber cloth is always higher than the temperature growth factor,and the strain rate has a higher effect on the compressive strength of the specimens than the temperature.The temperature growth factor of CFRP specimens is always higher than that of strain rate,and the influence of high temperature on compressive strength is higher than that of strain rate.The increase of temperature reduces the toughness of the three kinds of concrete specimens.The toughness of CFRP high temperature concrete at 0.3 MPa impact pressure and 25℃is 1.02 and 2.62 times that of CFRP and plain concrete,and 1.17 and 3.00 times at 600℃.The toughness of carbon fiber sheet high temperature concrete>high temperature carbon fiber sheet concrete>plain concrete.The restraint effect of carbon fiber sheet greatly enhances the toughness of the specimen.As the temperature increases,the energy dissipation density of the three kinds of concrete specimens decreases con-tinuously.The restraint effect of carbon fiber cloth can greatly enhance the energy dissipation effect of concrete mate-rials,and the energy absorption effect of using carbon fiber cloth for maintenance and reinforcement of concrete ma-terials increases more after high temperature action.关键词
高温/碳纤维布/约束混凝土料/应变率/力学性能/增长因子/复合材料Key words
high temperature/carbon fiber cloth/restrained concrete material/strain rate/mechanical proper-ties/growth factor/composites
