Experimental Study on Mechanical Properties of Grouted Sleeves with Different Materials

To clarify the differences in mechanical properties between the new seamless steel pipe rolled grouting sleeve and ductile iron fully grouted/semi-grouted sleeves, three groups of specimens (9 in total) were designed for uniaxial tensile tests. The failure modes, ultimate loads, ultimate displacements, and strain distribution laws of the specimens were analyzed. The results show that all three types of sleeves undergo complete elastic, yield, strengthening, and necking stages, with the failure mode being steel bar fracture in all cases. Among them, the new grouting sleeve exhibits the best ductility, followed by the ductile iron fully grouted sleeve, while the ductile iron semi-grouted sleeve shows the worst ductility. The most critical section of the new grouting sleeve is located at the first annular rib in the middle; for the ductile iron fully grouted sleeve, it is in the middle of the sleeve; and for the ductile iron semi-grouted sleeve, it is at the threaded end and the size-varying region. Based on the test results, structural optimization suggestions for the three types of sleeves are proposed, which provide a reference for the engineering application of grouting sleeves in prefabricated buildings.