On the influence of mixing modes on the quality of the foam-concrete mixture

In the article, for the preparation of a foam concrete mixture based on an analysis of a priori information, a one-stage technology for the preparation of a foam concrete mixture was used. Turbulent mixers are considered as a mixing device. A necessary condition for the applicability of the mixer is to ensure the suspension of particles in the mixing volume. The authors consider the features of mixing only such dispersed systems "solid phase - liquid", which are characterized by sufficiently high particle deposition rates, which is applicable to foam concrete mixtures. Cement-sand suspensions show a tendency to rapid separation after stopping mixing. The dependences of the homogeneity of the structure of the foam concrete mixture on the speed of rotation of the activator and the mixing time are considered. Based on the results of the study, the following conclusions are made. The effect of mixing speed on the uniformity of the foam concrete mixture was studied by us on a laboratory turbulent mixer with a conical part of 150 liters. Reflective partitions installed on the inside of the mixer body were used; the number of partitions was 4. A three-blade activator was used as a mixing organ. The control of the activator rotation speed was carried out by changing the gear ratio of the V-belt drive, for this a set of pulleys of different diameters was used. The rotation speed of the electric motor remained constant. The rational speed of rotation of the activator in the preparation of the foam concrete mixture of a given uniformity is in the range from 450 to 550 rpm; rational value of the mixing time, providing a given uniformity of the foam concrete mixture, is in the range from 3.5 to 5.5 minutes.