THE EFFECT OF MECHANICAL ACTIVATION IN A ROTARY BALL MILL ON THE PROPERTIES OF BINDER COMPOSITIONS WITH THE ADDITION OF VOLCANIC SAND

The paper investigates composite binders based on Portland cement and volcanic sand, subjected to mechanical activation in a rotary ball mill. The rational parameters of grinding (10, 30 and 50 minutes) and the filler content (10-30%) were determined. It was found that under optimal conditions, the specific surface area reaches 847.7 m2/kg, which is 2.83 times higher than that of commercial cement. The maximum compressive strength after 28 days (82.7 MPa) was obtained for a composition with 10% sand after 10 minutes of activation. The possibility of saving Portland cement up to 20-30% is shown, depending on the grinding mode. Mechanical activation in a rotary ball mill intensifies the hydration processes, however, with prolonged grinding (50 min), an ambiguous effect on strength characteristics is observed, depending on the proportion of filler. The resulting composites are recommended for the production of general-purpose and special-purpose concrete.