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

The requirements for the energy efficiency of building structures are based on the balance of costs for their manufacture, operation and the effect that is achieved by saving heat. In conditions of relatively low cost of energy carriers, the use of seamless insulation systems, including those based on light or heat-insulating plasters, becomes expedient. The developed facade light plaster system has, at an average density of 400–500 kg/m3, adhesion strength to the substrate of 1.3–1.6 MPa; compressive strength of 4.7–5.5 MPa; frost resistance of 50 cycles. The system has thermal in-sulation up to 0.12 W/(moС), which, with a plaster coating thickness of 50 mm and a thermal resistance of the main structure of 1.6-2.0 m2oС/W allows you to obtain a system with a total thermal resistance of up to 2.3 m2oС/W, which fully meets the conditions of comfort or technological requirements.

Keywords: adhesive strength, energy efficiency, seamless insulation, thermal resistance

The urgency of creating systems to stabilize and strengthen soils is due to the need to build buildings, structures and roads in regions where clay soils, as well as loams and sandy loams are widespread. The article formulates the main technological and technical requirements for stabilized soils. The principal possibility of applying a complex modification of the soil by introducing a composite composition of quicklime and finely ground granulated blast furnace slag in combination with mechanical compaction is considered. The results of studies of soil modification by composite composition are presented, the purpose of which is to make the soil suitable not only for the installation of anti-filtration curtains in soils during the development of pits, but also for foundations and basements. The results of studies of the properties of stabilized soil are presented.

Keywords: unstabilized soil, soil modification, loam, quicklime, ground slag, analytical optimization