硅烷涂层提升钢纤维-砂浆界面性能的试验研究

Experiment research on improving interface performance of steel fiber and mortal by silane coatings

为了提升钢纤维-砂浆界面的黏结性能,采用9种基于硅烷的表面处理剂对钢纤维进行浸渍处理并高温固化成膜;埋置于水泥砂浆圆柱体试块中,开展单根纤维拉拔试验,获得拉拔荷载-位移曲线.试验结果表明,采用不同的硅烷涂层对钢纤维进行表面改性,可以不同程度地改善钢纤维-砂浆界面的黏结性能;拉拔峰值荷载最高增加5.75倍,拉拔能耗最多增加2.48倍.硅烷Z6011和Z6020及复合涂层能够较大幅度地提升界面黏结强度,主要增加钢纤维与砂浆界面的化学黏结力;硅烷Z6030和Z6040及复合涂层对界面黏结强度的提升幅度相对较小,主要增加界面滑移摩擦力.采用扫描电子显微镜(SEM)研究界面黏结性能的提升机理,发现硅烷涂层使得界面过渡区的微观结构更致密,显著提升了钢纤维-砂浆之间的黏结性能.

Steel fibers were impregnated in nine types of silane based solutions and dried at a high temperature to form silane coatings in order to improve the interfacial bonding properties.The treated and untreated fibers were embedded in cylindrical specimens of cementitious mortar,and a single fiber pullout test was conducted to obtain load-displacement curves.The test results showed that surfacial treatment of steel fibers with different silane coatings improved the fiber and mortar interfacial bonding properties by different extents.The peak pullout load increased by a maximum of 5.75 times,and the energy consumption increased by a maximum of 2.48 times,respectively.Silane Z6011,Z6020 and their composite coatings can greatly improve the interfacial bonding strength.These coatings mainly increase the chemical bonding force between steel fiber and mortar.Silane Z6030,Z6040 and their composite coatings improve the interfacial bonding strength relatively small,and mainly increase the interface sliding friction.The scanning electron microscope(SEM)was used to observe the surface of steel fibers and the interfacial transition zone of steel fibers and cementitious mortar.Results show that the silane based solutions can effectively form coatings on the surface of steel fibers.The silane coatings made the microstructure of the interface transitional zone denser,leading to significant improvement on the bonding behavior between steel fibers and mortar.