Viscosity reduction of cementitious suspension under an ultrasonic effect

The application of ultrasound to particle suspensions has been widely studied to improve the properties of suspensions. Many studies have focused on the dispersive effect of ultrasound by cavitation in suspensions with low or medium volume fractions of solids. Although it was reported that the viscosity of particle suspensions can be reduced with increased dispersion, the role of ultrasound in decreasing the viscosity of dense particle suspensions has been elusive thus far. Here we quantitatively studied the effect of ultrasound on the viscosity of dense cementitious suspensions. The change in viscosity depends on the application time and the power of an externally imposed ultrasound. Aggregates and agglomerates in the suspension can be degraded by cavitation effects even with a high volume fraction of solid. In addition, it was observed that the effective viscosity of MTA (Mineral Trioxide Aggregate), a cementitious material for endodontic use, decreased while flowing in the microchannel, which can possibly improve the dental treatment. These results suggest that ultrasound can offer an attractive means to control the flow characteristics of cementitious materials for various applications.