Experimental Research On The Mechanical Behavior Of Grouted Sleeves With Fiber-Reinforced Grouting Material Under Cyclic Loading

The normal grouting material which has been widely used in traditional grouted sleeve connections has high brittleness and it often burst when broken. Moreover, these grouted sleeve connections required larger anchorage length and exhibited a worse cyclic load capacity than the steel bar. In this research, three kinds of fibers, including polypropylene fiber, polyvinyl alcohol fiber and basalt fiber, were selected as mixing materials in the grouting material. Their performance was tested in three areas: basic mechanical properties, toughness, and the optimal content and length of each fiber. Then, a total of 120 grouted sleeve connections with three selected optimal fiber grouting materials and five different anchorage lengths were manufactured. The mechanical performance of the grouted sleeves connections was tested under two loading schemes: cyclic loading at high stress (CH) and cyclic loading at large strain (CL). The compression test results of grouting materials demonstrated that fiber was an ideal material for improving the toughness of the grouting material. The optimal content of each fiber in grouting material was 0.5% (PP), 0.3% (BF) and 0.1% (PVA) and the optimal length was 9 mm (PP), 3 mm (BF) and 3 mm (PVA), respectively. Meanwhile, the minimum anchorage length of rebar in the grouted sleeves could be reduced by at least 1 d (d: diameter of rebar) when the fiber reinforced grouting material was adopted. According to the load-deflection curves under cyclic loading, the fiber reinforced grouted sleeve connections exhibited better residual deformation and stiffness degradation. Test results demonstrated that the fiber could clearly enhance the residual bond strength and ductility of the reinforced section, and the residual bond strength of the connections with the fiber grouting material could be increased by 3.8% similar to 22.8% when the steel bar was pulled out.