塑钢纤维掺量对钢筋与轻骨料混凝土粘结作用的影响

通过对钢筋与轻骨料混凝土进行拔出试验,探究塑钢纤维掺量对钢筋与轻骨料混凝土粘结作用的影响。以τ-s曲线描述试件粘结滑移的过程,用相对粘结强度衡量塑钢纤维掺量的影响作用,引入粘结韧性来分析塑钢纤维在试件粘结滑移过程中约束与耗能作用。结果表明:试件的破坏形态随纤维掺量的增加由劈裂破坏变为拔出破坏;钢筋的平均极限粘结强度τ_u、峰值滑移量s_u随纤维掺量的增加而增大;根据试验数据拟合出了相对粘结强度与塑钢纤维掺量的经验公式,可为工程设计提供参考;粘结韧性随纤维掺量的增加而提高,约束与耗能作用明显增强,但本试验塑钢纤维掺量超过6 kg/m^3后,韧性虽继续增长,但韧性增幅却呈下降趋势。

Influence of Plastic Steel Fiber Content on Bond between Lightweight Aggregate Concrete and Steel Bars

The effects of the content of plastic steel fiber on the bonding between rebar and lightweight aggregate concrete were investigated by pull-out test of rebar and lightweight aggregate concrete. The τ-s curve was used to describe the process of bond slip, and the effect of relative bond strength on the amount of plastic steel fiber and bond toughness was introduced to analyze the effects of constraints and energy dissipation of plastic steel fiber in the bond slip process of the specimens. The results show that the failure mode of the specimen changes from the cracking failure to the extraction failure with the increase of the fiber content. The average ultimate bond strength τ u and the peak slip s u amount of the steel bar increase with the increase of the fiber content. According to the experimental data, the empirical formula of relative bond strength and plastic fiber fiber content is fitted, which can provide reference for engineering design. The bond toughness increases with the increase of fiber content, and the restraint and energy consumption are obviously enhanced. However, after plastic steel fiber content exceeds 6 kg/m 3, the toughness continues to increase, but the toughness increase shows a downward trend.