GFRP管约束钢纤维混凝土短柱的声发射参数分析

Analysis of Acoustic Emission Parameters for GFRP Tube Confined Steel Fiber Reinforced Concrete Short Columns

摘要:

为研究钢纤维含量对玻璃纤维增强塑料管（GFRP）约束钢纤维混凝土（SFRC）短柱在轴向压缩荷载下的力学性能影响，利用声发射（Acoustic emission, AE）技术监测核心混凝土的损伤演化规律.结果表明，随着钢纤维含量从0%增加至1.8%，试件的峰值荷载和位移延性也随之增大，最大增幅分别为31.55%和15.60%.通过AE能量的演化趋势可以将试件的轴压过程分为三个阶段，其中AE能量在裂纹发展阶段表现最活跃，并出现Kaiser效应.从RA-AF的分布特征和混凝土的破坏模式可以发现，随着加载过程的进行和钢纤维含量的增加，剪切裂纹占比逐渐增多，利用RA-AF值可以定量的表征核心混凝土的破坏特征.b值的演化特征可以反映混凝土的破裂过程，弹性阶段b值的下降趋势可以作为试件破裂失稳的重要前兆信息，当b值达到最小值且趋于稳定时，试件发生极限破坏.

Abstract:

To investigate the influence of steel fiber content on the mechanical properties of glass fiber reinforced polymer (GFRP) confined steel fiber reinforced concrete (SFRC) short columns under axial compression, acoustic emission (AE) technology was employed to monitor the damage evolution of core concrete. The results demonstrated that as the steel fiber content increased from 0% to 1.8%, both the peak load and displacement ductility of specimens exhibited significant enhancement, with maximum increments reaching 31.55% and 15.60% respectively. The axial compression process could be divided into three distinct stages based on AE energy evolution trends, with the most active AE energy release observed during the crack development stage accompanied by Kaiser effect. Analysis of RA-AF distribution characteristics and concrete failure patterns revealed a progressive increase in shear crack proportion with both loading progression and steel fiber content elevation. The RA-AF values were found to quantitatively characterize the failure features of core concrete. The evolution characteristics of b-value effectively reflected the concrete fracture process, where the descending trend of b-value during the elastic stage served as critical precursor information for structural instability. Ultimate failure consistently occurred when the b-value stabilized at its minimum threshold.