玄武岩纤维增强混凝土破坏形态及弯曲韧性研究

Study on Failure Modes and Flexural Toughness of Basalt Fibers Reinforced Concrete

为综合评价玄武岩纤维混凝土处于弯曲载荷作用下的变形程度及其韧性与破坏形态特征的影响,重点研究了玄武岩纤维增强混凝土抗弯曲性能,测试了玄武岩纤维不同加入比例引起的弯曲韧性差异性。研究结果表明:不含纤维的混凝土试样到达峰值荷载时发生了裂缝的快速扩展,表现为明显的脆性断裂特征;加入体积分数为0.3%的玄武岩纤维,混凝土表面存在明显纤维,在断裂面部位的纤维与混凝土之间保持紧密连接的状态,侧面区域生成了竖向的细裂纹;逐渐提高玄武岩纤维体积分数后,试样获得了更高的峰值荷载,形成了更饱和的荷载—挠度曲线,达到了优异延展效果,弯曲韧性增长速率变慢。

In order to comprehensively evaluate the deformation degree,toughness and failure characteris-tics of basalt fibers reinforced concrete under bending load,the bending resistance of basalt fibers rein-forced concrete was mainly studied,and the difference of bending toughness caused by the different propor-tion of basalt fiber was tested.The results show that the concrete sample without fiber has a rapid crack ex-pansion when it reaches the peak load,showing obvious brittle fracture characteristics.When the basalt fi-ber volume fraction is 0.3%,there are obvious fibers on the surface of concrete,and the fibers on the frac-ture surface are closely connected with the concrete,and vertical fine cracks are generated in the side area.When the basalt fiber volume fraction is gradually increased,the sample obtains a higher peak load,forms a more saturated load deflection curve,achieves excellent extension effect,and the growth rate of bending toughness slows down.