Grouting sleeves are widely used in the field of assembled construction. The present study aims to investigate the reliability of grouting sleeves under large-deformation repeated tension and compression after high temperature, considering the influences of steel bar diameter, the cooling method, and the protective layer. Through experimentation on 28 test pieces, we analyzed the bonding performance of the test pieces at different high temperatures. The results indicate that within the temperature range of 20–800 °C, the bond performance of the test pieces declines by no more than 9.8%. However, upon reaching a temperature of 1000 °C, the bond performance of the test pieces decreases by over 33.7%, with the compressive strength of the grout material reduced to only 27.50% of that kept at 20 °C. Employing larger-diameter steel bars is advantageous for maintaining the bond performance of the test pieces. Natural cooling shows relatively good bond performance, although its influence is not significant. Furthermore, the protective layer effectively attenuates the heating rate of the test pieces, thus safeguarding their bond performance. Scanning electron microscopy (SEM) analysis reveals that the decomposition of C-H and C-S-H phases is the primary cause of high-temperature degradation of the grouting material. Finally, a recommendation for the correlation coefficient ($k$) between the average bond strength and the compressive strength of the grout material is proposed, with a suggested value of $k$ ≤ 2.58.

In this study, interface models of different polymer fibers and geopolymer products were constructed and the microscopic action mechanisms behind different polar oxygen-containing functional groups were revealed by analyzing the static structure of the interface and fiber pull-out process. The results show that, compared with polypropylene (PP) fibers, there is a strong hydrogen bond interaction in polyvinyl alcohol (PVA) and polyacrylic acid (PAA) fibers, respectively. After reaching equilibrium, the interlayer spacing of PVA and PAA fibers becomes smaller. At the interface, there are both ionic bonds and hydrogen-bonding connections, and the stability of ionic bonds is greater than that of hydrogen bonds. As the loading rate increases, the shear strength shows an increasing trend. Since the carboxyl of PAA fibers has stronger polarity than the hydroxyl of PVA fibers, the end deformation of the matrix is greater. During the pull-out process, the influence of the loading rate is greater than the anchoring effect of hydroxyl in PVA fibers but lower than that of carboxyl in PAA fibers.