钢-聚丙烯混杂纤维陶粒混凝土与钢筋黏结锚固性能试验研究

为了研究钢-聚丙烯混杂纤维陶粒混凝土与变形钢筋的黏结锚固性能,克服陶粒混凝土韧性差及其与钢筋黏结性能不佳的缺陷,对16组不同混杂比的钢纤维、聚丙烯纤维陶粒混凝土试件进行中心拉拔试验,得到混杂纤维掺量对陶粒混凝土与钢筋黏结破坏形态、黏结强度以及黏结滑移曲线的影响规律。采用能量法量化评价混杂纤维对黏结滑移的影响,利用试验数据计算得到钢-聚丙烯混杂纤维陶粒混凝土与钢筋的临界锚固长度。结果表明:钢-聚丙烯混杂纤维陶粒混凝土拉拔试件的破环形态为拔出破坏,延性较好; 黏结滑移曲线具有完整的上升段和下降段,钢纤维和聚丙烯纤维混掺对黏结强度可产生正混杂效应,钢纤维对黏结性能的改善起主导作用,聚丙烯纤维次之; 混杂纤维能大幅提升黏结滑移曲线的上升段及下降段能量吸收值,明显改善黏结韧性和变形能力; 混杂纤维陶粒混凝土的临界锚固长度较未掺纤维时可减小23%; 掺入钢-聚丙烯混杂纤维能显著改善陶粒混凝土与变形钢筋的锚固黏结性能,提高黏结延性,减小陶粒混凝土与变形钢筋的的锚固长度。

Experimental Study on Bond Anchorage Performance Between Steel-polypropylene Hybrid Fiber Ceramsite Concrete and Reinforcement

In order to study the bond and anchorage performance of steel-polypropylene hybrid fiber ceramsite concrete and deformed reinforcement, and overcome the defects of poor toughness of ceramsite concrete and poor bond performance with reinforcement, 16 groups of steel fiber and polypropylene fiber ceramsite concrete specimens with different hybrid ratios were subjected to central pull-out test, and the effects of hybrid fiber content on the bond failure mode between ceramsite concrete and reinforcement, bond strength and bond slip curve were obtained. The influence of hybrid fiber on bond slip was quantitatively evaluated by energy method. The critical anchorage length between steel-polypropylene hybrid fiber ceramsite concrete and reinforcement was calculated by the test data. The results show that the breaking form of steel-polypropylene hybrid fiber ceramsite concrete pull-out specimens is pull-out failure and the specimen has good ductility. The bond slip curve has a complete rising section and falling section. The mixing of steel fiber and polypropylene fiber can produce a positive hybrid effect on the bond strength. Steel fiber plays a leading role in the improvement of bond performance, followed by polypropylene fiber. The hybrid fiber can greatly increase the energy absorption value in the rising and falling sections of the bond slip curve, and significantly improve the bond toughness and deformation ability. The critical anchorage length of hybrid fiber ceramsite concrete can be reduced by 23% compared with that without fiber. Adding steel-polypropylene hybrid fiber can significantly improve the anchorage and bonding performance between ceramsite concrete and deformed reinforcement, improve the bond ductility and reduce the anchorage length of ceramsite concrete and deformed reinforcement.