The use of methods for strengthening soils with Portland cement makes it possible to increase the physical and mechanical properties of soils: strength, frost resistance, water permeability, etc. A technical understanding of the processes of structure formation in reinforced soils makes it possible to regulate the final properties and quality of the layers of highways. To describe the processes of structure formation, it is possible to use the theory of contact interactions and the theory of DLFO. The final properties of the reinforced soil are influenced by the following factors: mineralogy and specific surface area of the soil, water content, amount of cement, curing time and method of compaction.

Keywords: stabilized soils, structure formation of stabilized soils, stabilization with Portland cement, properties of stabilized soils

The use of ash and slag mixtures of thermal power plants in the structures of road coverings of highways makes it possible to significantly increase the volume of their reuse. One of the promising directions is their application in the compositions of stabilized soils. To assess the effectiveness of the use of these materials, such indicators as the cost of construction and the total thickness of the pavement structure are used. According to the results of the conducted research, it was found that the reduction in the total thickness of road clothing with layers of ash and slag mixtures of CHP compared with layers of traditional materials was up to 48%, the reduction in the cost of building road clothing structures using ash and slag mixtures is up to 21%.

Keywords: stabilized soils, ash and slag mixtures, road clothing, base of road clothing

The features of the calculation of nodal joints of frame buildings made of cold-formed steel profiles are considered. The connection of elements of frame buildings made of cold-formed steel profiles for the perception of acting forces is made on bolts using low-carbon steel shapes, the profiles themselves are made of thin-sheet galvanized rolled products. But there are no requirements for the thickness of the shapes and specific thickness values depending on the applied forces in the regulatory documentation, since these compounds are poorly studied in Russia. The calculation of frame buildings made of cold-bent steel profiles and the analysis of nodes with bolted connections was carried out and a method for determining the number of bolts in nodes in two design cases depending on the thickness of the shape was proposed, the need to introduce these requirements into the regulatory documentation for thin-walled structures was shown.

Keywords: cold-formed profile, hot-dip zinc-coated steel sheet, frame building, node, single-bolt connection, shape, crumple, truss, thin-walled structures