Mathematical modeling of the working body’s oscillatory motion in a concrete mixer

Abstract

This study investigates the concrete mixing process in a gravity mixer and proposes strategies to enhance its efficiency. The challenge of uneven component distribution, arising from passive-zone formation, was addressed through a mathematical model developed to describe particle-motion kinematics within the mixing drum. Numerical simulations demonstrated that mixing efficiency is strongly influenced by drum rotation speed, inclination angle, blade configuration, and oscillatory motion. Introducing oscillations was found to increase the intensification coefficient by 15–18 %, reduce the passive-zone area from 28 % to 15 %, and improve mixture uniformity by 12–15 % in terms of the variation coefficient. Furthermore, oscillatory motion accelerates the growth of homogeneity: a rapid increase begins as early as 2 min, reaching the mixing intensity factor 0.8 by 4 min, corresponding to high-quality mixing. In contrast, without oscillations, a comparable level of homogenization is achieved only after 6–7 min of drum operation. The findings confirmed the effectiveness of oscillatory drum motion as a practical approach to improving mixing quality, reducing energy demand, and optimizing the structural design of concrete mixers.