Study on the structure and properties of non-water reacted polyurethane grouting materials

Abstract In this study, non-water reacted polyurethane grouting materials were prepared using three different molecular chain lengths of polyether polyols. The influence of polyols and -NCO/-OH index (R x ) on the initial viscosity, mechanical properties, and concrete adhesion performance was investigated. Additionally, the damping performance of the cured materials was evaluated using dynamic mechanical analysis (DMA). The research results showed that with an increase in the molecular chain length of the polyether polyols, the strength of the cured material significantly decreased, while the elongation at break increased noticeably. Compared to the molecular chain length of the polyether polyols, the effect of the Rx on the mechanical properties of the cured material was not significant, especially in the low molecular weight polyether polyol system with shorter molecular chains (G3). The adhesion strength of the non-water reacted polyurethane grouting materials to concrete was highly correlated with the gelation time, and a slow gelation time could result in the formation of foam-like structures and reduce the adhesion strength. Grouting materials with shorter molecular chain lengths combined with low R x (G3-1.0) or medium molecular chain lengths combined with moderate R x (G5-1.4) exhibited excellent mechanical and damping properties.