Properties of calcium sulfoaluminate cement-based grouting materials with LiAl-layered double hydroxides slurries

In this study, LiAl-layered double hydroxides Lithium aluminum hydrotalcite (LiAl-LDH) with different specific surface area were prepared by the separate nucleation and aging steps (SNAS) method and then were employed to prepare calcium sulfoaluminate cement-based grouting material (CBGM) paste. The influence of LiAl-LDH slurries on fresh and hardened properties of the CBGM paste was investigated in terms of fluidity, stability, setting time, and compressive strength. Additionally, the hydration process and hydration products of the CBGM paste were characterized by hydration heat, X-ray diffraction, differential thermal analysis–thermogravimetry, and Fourier transform infrared analyses. The acquired results illustrated that LiAl-LDH with larger specific surface area led to a faster hydration rate at early age, a lower fluidity, a shorter setting time, and a higher stability. Furthermore, due to the crystal nucleation effect, the addition of LiAl-LDH slurries did not cause a new phase to form but changed the morphology and increased the amount of hydration products, yielding higher compressive strength.