The composition of the lightweight plaster mix includes the following components: hydraulic binder, crushed volcanic tuff-scoria (as a fine lightweight filler), reinforcing fiber and synthetic additive. The hydraulic binder consists of Portland cement and finely ground volcanic tuff. Plaster mixes based on volcanic tuff are in demand in regions with a warm or sharply continental climate: high temperatures during the day or low at night, including Ethiopia. The purpose of the research presented in the article was: to form material structure models that allow evaluating the material properties and evaluating the solutions obtained during the implementation of an active experiment. As a result of the experiment, optimal values ​​​​of the main components of the plaster mix based on volcanic tuff were established, which is present in the mixture as a light fine filler and as a component of the hydraulic binder. Modeling of the material structure and engineering interpretation of its properties were carried out.

Keywords: plaster material, tuff-scoria, pozzolanic activity, mathematical modeling, analytical optimization