硅灰和SBL对钢纤维砂浆结构和强度的影响

采用硅灰增强和丁苯乳液增强2种方式对钢纤维-水泥基体界面过渡区进行增强,以改善钢纤维砂浆的微观结构和力学性能.测试了硅灰、丁苯乳液增强钢纤维砂浆3,28,90 d龄期的抗压、抗折强度.同时,以微观图像和理论分析研究了不同增强方式下钢纤维、水泥基体的受力与破坏特点.根据测试与分析结果,提出了刚性、柔性增强钢纤维-水泥基体界面过渡区的概念,认为硅灰刚性增强钢纤维-水泥基体界面,而丁苯乳液则柔性增强钢纤维-水泥基体界面.刚性增强界面增加了钢纤维桥接作用失效的几率;而柔性增强界面则不存在纤维失效问题,从本质上揭示了不同增强方式对钢纤维砂浆长期力学性能作用的差异性.

Effect of Silica Fume and Styrene-Butadiene Latex on the Microstructure and Mechanical Performance of Steel Fiber Mortar

The interface between steel fiber and cement matrix could reduce the reinforced effect of fiber in fiber mortar.Two different reinforced methods are introduced to intensify the interface so as to improve the microstructure and mechanical performance of fiber mortar,and these two methods are named silica fume(SF) reinforced and styrene-butadiene latex(SBL) reinforced.The compressive and flexural strengths of mortar aged at 3,28,90 d are tested.The stress characteristics of the steel fiber are studied by mean of theory calculation,and the rupture characteristics of steel fiber and matrix are studied by mean of SEM image.Based on those studies,the conception of rigidity reinforced and flexible reinforced of the interface is proposed.SF is attributing to rigidity reinforced of the interface,while SBL is attributing to flexible reinforced of the interface.In the method of rigidity-reinforced of the interface,fiber bridge effect decreases,leading to the decrease of reinforced effect,while in the method of flexible reinforced of the interface,it does not have such problem.The diversity of different reinforced methods on the long-term mechanical performance is gained essentially.