玄武岩纤维混凝土梁斜截面受剪试验

Experimental Research on Shear Capacity of Inclined Section of Basalt Fiber Reinforced Concrete Beams

目的研究玄武岩纤维的掺入对混凝土梁斜截面开裂荷载和极限荷载的影响.方法以玄武岩纤维长度及纤维体积掺率为参数,设计并制作了4根掺有纤维长度分别为12 mm和30 mm,纤维体积掺率分别为0.1%和0.2%的纤维混凝土梁.通过受剪试验,获得了相关试验数据.结果与普通钢筋混凝土梁对比,随着纤维特征参数的增大,玄武岩纤维混凝土梁斜裂缝开裂荷载及极限荷载均有显著增大,且裂缝宽度发展较缓慢,同级荷载作用下裂缝宽度减小.纤维长度为12 mm,体积掺率分别为0.1%和0.2%的纤维混凝土梁与普通钢筋混凝土梁相比,抗剪承载力分别提高了5.93%和13.43%;纤维长度为30 mm,体积掺率分别为0.1%和0.2%的纤维混凝土梁与普通钢筋混凝土梁相比,抗剪承载力分别提高了19.06%和21.88%.结论玄武岩纤维的掺入增大了砂浆与粗骨料之间的粘结力,提高了混凝土的抗拉强度,从而抑制了梁斜裂缝的开展,并使箍筋和纵筋与混凝土的机械咬合力增大.提出的玄武岩纤维混凝土梁斜截面受剪承载力计算方法,为工程实践提供理论依据.

This paper researches the influence of the cracking and ultimate load of the inclined section of concrete beam with the incorporation of basalt fiber.Four basalt fiber reinforced concrete beams with parameters of fiber length and volume ratio were designed and made,where fiber lengths were 12 mm and 30mm,and the volume ratios were 0.1% and 0.2%.The test data of basalt fiber reinforced concrete was obtained through the shear experiments.In contrast with the common reinforced concrete beam,the cracking and ultimate load of the basalt fiber reinforced concrete beam increase obviously with the growing of fiber characteristic parameters,and the crack width develop slowly and reduce under the same load.The cohesive force between mortar and coarse aggregate increase with the basalt fiber mixing,and the tensile strength of concrete is enhanced,thus the extension of inclined cracks are restrained,and the mechanical bit force between stirrup and longitudinal bar increase.The results of the experiment show that the four beams＇ whose the fiber lengths were 12 mm and 30 mm,and the volume ratios were 0.1% and 0.2% shear capacity are improved respectively 5.93%,13.43%,19.06%,21.88% comparison with the common reinforced concrete beam.Based on the results and analysis,the calculation method of the shear capacity of basalt fiber reinforced concrete beam is proposed,which can provide the theoretical basis for the engineering practice.