Optimization of grouting performance of nano calcium aluminate cement via gradient anhydrous wet-milling

To develop a grouting material with high injectability and early strength, gradient anhydrous wet-milling was proposed to reduce aluminate cement powder to the nanoscale. High-efficiency sand milling using anhydrous ethanol as the dispersion medium achieved cement particle nano-sizing. Mechanical properties, including compressive and flexural strengths, alongside pumpability, were comprehensively evaluated. Furthermore, XRD, SEM, and laser particle size analysis systematically characterized phase composition, micromorphology, surface features, and particle size distribution. The results demonstrate that this method yields nano-cement with significantly reduced particle size and a remarkably increased specific surface area. The median particle size reached 468 nm with a BET specific surface area of 10.1897 m 2 /g, without generating impurity phases. At a water-to-cement ratio of 1.0, the slurry exhibited sufficient fluidity and low pumping resistance, showing viscosity characteristics well-suited to pumping requirements. The 3-day compressive strength reached 9.13 MPa, highlighting a prominent early strength advantage. These findings provide a scientific basis for developing next-generation grouting materials combining excellent injectability with high early strength.