圆钢管玄武岩纤维再生混凝土短柱轴压力学性能

Axial compressive property of circular steel tubular stub column filled with basalt fiber reinforced recycled concrete

为研究圆钢管玄武岩纤维再生混凝土(BFRRC)短柱的轴压力学性能,以再生粗骨料取代率和玄武岩纤维掺量为变化参数,设计并完成了15根圆钢管BFRRC短柱试件的轴压试验。观察了试件的受力全过程及破坏形态,获取了试件的荷载-位移曲线及荷载-应变曲线,分析了变化参数对圆钢管BFRRC短柱轴压性能的影响,建立了可行的组合截面应力-应变全过程曲线方程。研究表明:试件均发生鼓曲破坏,但核心混凝土在钢管约束下处于碎而不散状态;随着再生粗骨料取代率的增大,试件的耗能性能、延性系数逐渐增大,耗能因子、延性系数提升幅度最高可达1.84%和10.36%,承载力逐渐降低,降低幅度最大达5.03%;随着玄武岩纤维掺量的增大,试件的耗能性能、延性系数逐渐增大,增加幅度最高可达2.97%和4.93%,承载力提高幅度不大;不同的玄武岩纤维掺量下,试件实测的荷载-位移曲线饱满,且具有较长的变形流幅,延性较好。

To study the axial compressive performance of basalt fiber reinforced recycled concrete(BFRRC)-filled circular steel tubular stub columns,the replacement ratio of recycled coarse aggregate and the content of basalt fiber were designed as the variable parameters and the axial compression performance tests on 15 BFRRC-filled circular steel tubular stub column specimens were carried out.The failure mode and whole loading process of the specimen were characterized.The load-displacement and load-strain curves of the specimen were obtained.The influence of design parameter on the BFRRC-filled circular steel tubular stub column specimens was analyzed.A feasible full-curve equation of composite-section stress versus strain was established.It is observed that the specimen undergoes buckling damage,but the internal BFRRC is crushed but“broken and not scattered”.On increasing the replacement ratio of recycled coarse aggregate,the energy dissipation capacity and ductility coefficient of the specimen are gradually increased,the maximum increasing extent for energy dissipation capacity and ductility coefficient are 1.84%and 10.36%,respectively,whereas the bearing capacity is gradually decreased,and the maximum increasing extent of bearing capacity is 5.03%.On increasing the basalt fiber content,the energy dissipation capacity and ductility coefficient of the specimen are gradually increased,the maximum increasing extent for energy dissipation capacity and ductility coefficient are 2.97%and 4.93%,respectively,whereas little increase appears about the bearing capacity.The measured load-displacement curve of the specimen with different basalt fiber content is full,and it has a long deformation flow,which presents satisfactory ductility.