Dispersion of microfine cement grout with ultrasound and conventional laboratory dissolvers

Grout based on microfine cement is mainly used for sealing of rock fractures in underground construction with high sealing requirements. This grout is known as hard dispersed, compared to grouts based on ordinary Portland cement. This study investigates the possibility of using ultrasound to improve the dispersion of microfine cement grout. Ultrasound dispersion is compared with dispersion efficiency of an ordinary laboratory mixer equipped with a disk, and using the rotor-stator technique. Dispersion efficiency was measured with a filter pump. The grout dispersed with the laboratory mixer and disk could not pass through a 154 µm filter. The laboratory mixer using the rotor-stator technique showed much better efficiency, with a measured dispersion that varied between 77 and 104 µm. Dispersion with ultrasound yielded more reliable results, with lower variation; the grout passed through a 77 µm filter. These results showed that a laboratory mixer with a disk is not an effective method for dispersion of microfine cement. A laboratory mixer using the rotor-stator method is much more effective. Ultrasound is not only an effective method but is even better than a mixer using the rotor-stator technique