Improving the physical and mechanical properties of fortified soil for road construction in the forest zone

In order to purposefully control the processes that determine the formation of the structure and properties of cement soils, studies were carried out on the strengthening of soils with Portland cement with a water-soluble additive hydropropylene emulsion (WHE). The purpose of the laboratory studies was to study the change in the ultimate strength in compression, water saturation and frost resistance of cement soils, depending on the particle size distribution of the original soil, the amount of mineral binder-Portland cement and the WHE additive. Based on the results of the research, soil strengthening with Portland cement with WHE additive allows to form a complex crystallization-coagulation structure of materials with the required values of compressive strength, water saturation and frost resistance, depending on the dosages of binding components for given climatic and transport-operating conditions. The effectiveness of the WHE additive increases with increasing dispersion of soils, so the technology of strengthening of clay soils in conditions of wet and acidic soils of the forest zone for the construction of forest roads is promising. © Published under licence by IOP Publishing Ltd

Analytical Investigation of Projectile Motion in Midair

Here is studied a classic problem of the motion of a projectile thrown at an angle to the horizon. The air drag force is taken into account as the quadratic resistance law. An analytic approach is used for the investigation. Equations of the projectile motion are solved analytically. All the basic functional dependencies of the problem are described by elementary functions. There is no need for to study the problem numerically. The found analytical solutions are highly accurate over a wide range of parameters. The motion of a baseball and a badminton shuttlecock are presented as examples

Simple analytical algorithm for constructing the envelope of the projectile trajectories in midair

A classic problem of the motion of a projectile thrown at an angle to the horizon is studied. The air drag force is taken into account asthe quadratic resistance law.An analytic approach is used for the investigation. Simple analytical formulae are used for constructing the envelope of the family of the projectile trajectories. The equation of envelope is applied for the determination of the maximum range of flight. The motion of a baseball is presented as an example

The use of ash-mineral mixtures for the construction of high-strength coatings of forest roads

Forest roads are characterized by difficult transport and operating conditions and a considerable distance from sources of traditional road-building materials. Local ash and slag waste of the state district power station is an effective road-building material for the construction of forest roads. The article presents the test results of the building properties of the ash of the Reftinskaya TPP and the physicomechanical characteristics of the ash-mineral mixtures prepared with its use. Based on the results of laboratory studies, technical solutions for the use of ash-mineral mixtures in the design and construction of high-strength coatings of forest roads have been developed: the main design indicators, requirements for the materials used in the composition, approximate compositions of the ash-mineral mixtures are given, technical measures for the organization and quality control of construction work are assigned. © Published under licence by IOP Publishing Ltd