玄武岩纤维混凝土与钢筋粘结锚固性能试验与分析

Experiment and Analysis of Bond-anchorage Properties Between BFRC and Steel Bars

为了研究玄武岩纤维混凝土(BFRC)与钢筋粘结锚固性能,对18个中心拔出试件和9个梁式试件进行加载试验,获得各级荷载下加载端、自由端滑移量及钢筋应变,得到了粘结应力-滑移曲线和粘结应力沿锚固长度的曲线分布。试验结果表明:随着玄武岩纤维的掺入,钢筋与混凝土粘结锚固性能未表现出有利影响,极限粘结强度有所降低;掺入长度为25mm纤维的混凝土与钢筋的极限粘结强度优于掺入长度为15mm纤维的混凝土与钢筋的极限粘结强度;混凝土强度的提高有利于改善玄武岩纤维混凝土与钢筋粘结锚固性能,混凝土相对保护层厚度对粘结锚固性能影响不大;锚固钢筋的应变曲线整体呈下凹形,沿锚固长度逐渐递减;粘结应力沿锚固长度呈多峰曲线;基于试验数据建立的玄武岩纤维混凝土与钢筋粘结应力-滑移本构关系可以为玄武岩纤维混凝土的理论与工程设计提供参考依据。

In order to study the bond‐anchorage properties between basalt fiber reinforced concrete （BFRC） and steel bars ,the loading end ,the free end slip and strain of steel bars under various loads were acquired .Bond stress‐slip curves and bond stress curves along anchorage length were obtained through 18 center pull‐out specimens and 9 beam specimens＆#39;loading experiment .The experiment results show that basalt fiber has an adverse impact on the bond‐anchorage properties between steel bars and concrete and reduces the ultimate bond strength .25 mm basalt fiber shows greater ultimate bond strength between concrete and steel bars than 15 mm basalt fiber . The bond‐anchorage properties between BFRC and steel bars will be improved with the increase of the concrete strength .Relative thickness of concrete cover has little effect on bond‐anchorage properties .Strain curves of anchor steel bars are concave as a whole and decrease gradually along anchorage length . The bond stress curves along anchorage length are multimodal . The constitutive relation of bond stress and slip between BFRC and steel bars on the basis of experiment data can provide reference for the theory and engineering design of BFRC .