摘要
为研究高温后钢-聚乙烯醇(polyvinyl alcohols,PVA)混杂纤维高性能混凝土(hybrid fiber high performance concrete,HFHPC)与变形钢筋的黏结性能退化规律,以200、400、600、800℃为目标温度,选取钢纤维体积率、PVA纤维体积率、矿粉掺量为正交试验因素设计并制作25组HFHPC试件,完成了单调荷载下的中心拉拔试验。结果表明:高温后各组HFHPC试件黏结破坏形态均表现为钢筋拔出破坏;试验温度范围内,对HFHPC试件黏结强度的影响程度均为:钢纤维体积率最大、矿粉掺量次之、PVA纤维体积率最小;随着温度的升高,HFHPC试件黏结强度逐渐下降,且在相同温度条件下,HFHPC试件黏结强度和峰值滑移相比于未掺纤维的混凝土试件均有所提升,其中,200℃时HFHPC试件的黏结强度提升最为显著,分别提升了33.69%、35.76%、37.54%和46.03%;混杂纤维能显著提高高温后高性能混凝土与钢筋的峰值界面能,明显改善黏结延性和耗能能力;提出的考虑温度作用后的混杂纤维混凝土与钢筋黏结-滑移模型与试验实测结果吻合较好,可为火灾后混杂纤维高性能混凝土结构损伤评估及加固方案提供参考。
In order to research the effects of elevated temperatures on bond behavior between steel-polyvinyl alcohols(PVA)hybrid fiber high performance(HFHPC)concrete and deformed reinforcement.With 200,400,600,800℃as the target temperatures,25 sets of HFHPC specimens were designed by selecting volume fraction of steel fiber and PVA fiber and dosing of mineral powder as the orthogonal test factors.The central pull-out test under monotonic loading was cedompleted.Results show that the bonding failure modes of all groups of HFHPC specimens after high temperature are rebar pullout damage.Within the test temperature range,the volume fraction of steel fiber plays the most important role in bond strength,follows by mineral powder dosage,whereas the PVA fiber volume fraction has the minimum effect.With the increase of temperature,the bond strength of HFHPC specimens gradually decreases.Compared to the concrete specimens without fibers doping,the bond strength and peak slip of HFHPC specimens are increased under the same temperature conditions.The bond strength of HFHPC specimens is most significantly increased at 200℃,which is increased by 33.69%,35.76%,37.54%,and 46.03%,respectively.The hybrid fibers significantly improve the peak interfacial energy between high performance concrete and steel reinforcement after high temperatures,significantly improve the bond ductility and energy dissipation capacity.The proposed bond-slip curves of hybrid fiber concrete and deformed reinforcement after considering the temperature effect are in good fit with the experimental measured results,which can provide a reference for the structural damage assessment of hybrid-fiber high-performance concrete and the reinforcement scheme after fire.
作者
许成祥
吕红杰
许奇琦
朱红兵
XU Cheng-xiang;L Hong-jie;XU Qi-qi;ZHU Hong-bing(School of Urban Construction,Wuhan University of Science and Technology,Wuhan 430065,China;Hubei Provincial Engineering Research Center of Urban Regeneration,Wuhan 430065,China;Institute of High Performance Engineering Structure,Wuhan University of Science and Technology,Wuhan 430065,China)
出处
《科学技术与工程》
北大核心
2024年第20期8615-8623,共9页
Science Technology and Engineering
基金
湖北省高等学校优秀中青年科技创新团队计划项目(T2022002)。
