基于声发射的钢纤维再生混凝土动态损伤研究

Study on Dynamic Damage Evolution of Steel Fiber Reinforced Recycled Aggregate Concrete Based on Acoustic Emission Technology

摘要:

为进一步探究再生粗骨料在绿色建筑中的可持续应用，本文采用巴西圆盘劈裂试验和声发射技术，研究了动态荷载下钢纤维掺量（0，0.5%，1.0%，1.5%）、再生骨料替代率（0，30%，50%，100%）和加载速率（0.02mm/s,，0.20mm/s，2.00mm/s）对钢纤维再生混凝土力学性能和内部损伤演化的影响。结果表明，再生骨料会降低再生混凝土的动态劈拉强度，而掺入1.0%和1.5%钢纤维不仅可以有效地改善这种负面影响，还能增强混凝土的韧性和吸能能力。本文中动态劈拉强度增幅最大可达10%。此外，还利用上升角和平均频率的变化来反映混凝土的动态裂纹形态演变过程，发现剪切裂缝数量占比随加载速率的增大而增加，为实际工程的再生骨料掺量控制提供参考。

Abstract:

Abstract: Aiming at further exploring the sustainable application of recycled coarse aggregate in green buildings, the influences of steel fiber contents (0, 0.5%, 1.0%, 1.5%), recycled aggregate replacement ratios (0, 30%, 50%, 100%) and loading rates (0.02mm/s, 0.20mm/s, 2.00mm/s) on the mechanical properties and internal damage evolution of steel fiber reinforced recycled aggregate concrete (SFRAC) under dynamic tensile loads were studied using Brazilian disc splitting test and acoustic emission technology. The results indicate that the recycled coarse aggregate makes the dynamic splitting tensile strength of recycled concrete worse significantly. But 1.0% and 1.5% steel fiber can not only effectively improve this negative effect, but also enhance the toughness and energy absorption capacity of concrete. The maximum increase in dynamic split tensile strength is 10%. Furthermore, the evolution of crack pattern of SFRAC under dynamic axial tensile load is well reflected by the rise angle and average frequency, and the proportion of shear cracks increases with the loading rate raising, providing reference for the control of recycled aggregate content in actual engineering.