钢筋再生混凝土构件高温损伤分析

以本课题组前期完成的120个棱柱体试块,25根钢筋再生混凝土短柱和32根钢筋再生混凝土梁试件高温后力学性能试验数据为基础,深入分析了再生粗骨料取代率和历经最高温度对再生混凝土试块和钢筋再生混凝土构件高温损伤及力学性能变化规律的影响。研究结果表明:随着温度的升高,再生混凝土试块、钢筋再生混凝土构件发生了相似的物理现象,表面颜色由青灰色逐渐变为灰白色、表面出现微裂缝、质量减少,其质量烧失率逐渐增大。随温度的升高,各试件峰值荷载逐渐下降;受剪梁的峰值变形、延性、耗能受温度影响显著,且随温度的升高均呈下降的趋势;受弯梁的峰值变形、延性、耗能受温度影响不明显;试块和柱的峰值变形、延性、耗能受温度影响波动较大,没有呈现明显的规律。随取代率的提高,受剪梁的峰值变形、延性和受弯梁的延性出现较大波动,其余各试件的受力性能指标受取代率影响不明显,延性、耗能呈小幅下降的趋势,承载力、峰值变形呈小幅增大的趋势。

High temperature damage analysis of reinforced recycled concrete members

Based on the experimental data of mechanical properties of 120 prism specimens, 25 reinforced recycled concrete short columns and 32 steel reinforced recycled concrete beams subjected to high temperature, which are obtained from the former experiment, the effect of recycled coarse aggregate replacement ratio r and subjected maximum temperature T on the high temperature damage and mechanical properties of recycled concrete specimens and steel reinforced recycled concrete members were analyzed.Results show that with with the increase of temperature, similar physical phenomenon occurs in recycled concrete test blocks and steel reinforced recycled concrete members. The surface color gradually changes from green to gray, and the surface was slightly cracked, the quality was reduced, and the mass loss rate was gradually increased. It is shown that the peak deformation, ductility and energy dissipation o the shear beams are significantly affected by the temperature, and appeared a decreasing trend with the temperature increase. While the influence of temperature on the peak deformation, ductility and energy dissipation of flexural beams is not obvious? The peak deformation, ductility and energy dissipation of the blocks and columns fluctuate greatly with temperature but haven't obvious regulation. It also indicates that the increase of recycled coarse aggregate replacement ratio will cause large fluctuations on the peak deformation, ductility and energy dissipation of the shear beams, the mechanical behavior of the other test pieces are not obviously affected by the replacement ratio, the ductility and energy dissipation showed a slight decline, as the bearing capacity and peak deformation tend to increase slightly.