BFRP筋混凝土粘结-滑移声发射特性研究*

为研究BFRP筋与混凝土粘结-滑移过程中的损伤特征,对BFRP筋混凝土粘结试件进行了加载速度为0.1 mm/s的拔出试验。采用声发射技术对损伤过程的特点进行了研究,并且针对破坏预警指标的有效表征进行了深入分析。结果表明,声发射能量、撞击数、振铃计数等参数能够真实反映BFRP筋混凝土粘结受载情况,并得到250 kHz～300 kHz频段的声发射事件百分比及声发射b值范围可以作为粘结应力达到峰值时的预警指标,为BFRP筋混凝土粘结-滑移破坏预警提供了依据。

Experimental study on AE characteristics of bond-slip for the BFRP reinforced concrete

In order to study the damage characteristics of BFRP bars and concrete during the bond-slip process, the BFRP reinforced concrete specimens were subjected to pull-out test with a speed of 0.1 mm/s. The characteristics of the damage process were studied by acoustic emission technology, and the effective characterization of the damage warning indicators was analyzed. The results show that the parameters such as acoustic emission energy, impact number and ring count can truly reflect the bond loading of BFRP reinforced concrete. The percentage of acoustic emission events in the 250~300 kHz band and the range of acoustic emission b value can be used as an early warning indicator when the bond stress reaches the peak value, which provides a basis for the early warning of BFRP reinforced concrete bond slip damage.