This study develops a slip-hardening straight steel fiber in ultra-high-performance concrete (UHPC). For this, a surface treatment using sandpaper with various grits was adopted in both parallel and perpendicular directions to the fiber axis. Surface roughness was assessed by atomic force microscopy (AFM), and its correlation with the pullout resistance was evaluated. Test results indicate that although the surface treatment using sandpapers in both parallel and perpendicular directions is effective for enhancing the pullout resistance of straight fiber in UHPC, the latter is recommended since it exhibits better slip-hardening characteristics. The benefits resulting from inclination were more significant in the sanded fiber case and increased with increasing the grit. The higher surface roughness resulted in better pullout resistance, and the effectiveness was higher when the fibers were aligned. The sanded fiber achieved superior resistance and excellent slip-hardening response but exhibited smaller magnitude of frictional shear stress than the twisted fiber.

这项研究开发了一种超高性能混凝土（UHPC）中的滑动硬化直钢纤维。为此，在与纤维轴平行的方向和垂直的方向上都使用了具有各种粗砂的砂纸的表面处理。通过原子力显微镜（AFM）评估表面粗糙度，并评估其与抗拉强度的相关性。测试结果表明，尽管在平行和垂直方向上使用砂纸进行表面处理可以有效地增强UHPC中直纤维的抗拉强度，但仍建议使用后者，因为它具有更好的滑爽硬化特性。在砂纸情况下，倾斜带来的好处更为显着，并且随着粒度的增加而增加。表面粗糙度越高，抗拔出性越好，纤维排列后效果更好。磨毛的纤维具有优异的抵抗力和优异的滑移硬化响应，但与绞合纤维相比，摩擦剪应力的大小较小。