Improving the environmental situation and obtaining cement composites with new properties for various operating conditions is possible with the use of secondary resources. The paper is devoted to the criteria for evaluating the impact of clinker-free cement on the environment. The methodological approach to the selection of a functional unit for comparative assessment of the ecological footprint of clinker-free cements is justified. The results of studying the properties determining the concrete durability in the aggressive environment of livestock farms and in transport construction are given. The results will contribute to the development of an ecological approach to the components selection for clinker-free cements and to the adoption of design decisions in construction, as well as to the expansion of the field of using clinker-free cements in transport and industrial construction.

The physical and mechanical characteristics of expanded-clay lightweight concrete based on a supersulfated binder in comparison with lightweight concrete based on ordinary Portland cement were studied. In replacing CEM 32.5 with a supersulfated binder of 6000 cm²/g specific surface, one can increase the tensile strength in bending up to 20% and can increase the ratio of the tensile strength in bending to the compressive strength that indicates the crack resistance increase of concrete. Compressive strengths at the age of 28 days were equal to 17.0 MPa and 16.6 MPa for the supersulfated binder of 3500 cm²/g specific surface and CEM 32.5, respectively. Shrinkage deformation of hardening concrete, indicators of fracture toughness, frost resistance, and thermal conductivity were determined during the experimental works. The coefficient of thermal conductivity decreased up to 12% compared to the use of CEM 32.5. An enhancement in concrete properties was associated with the increase of supersulfated binder fineness.

Ensuring safety in rail transportation is achieved by creating a certain management structure of the company, which contributes to the improvement of economic sustainability and organization of safe traffic. The analysis of indicators to assess the state of traffic safety in JSC “Uzbekistan Temir Yullari” (the object of the study) allowed the authors to formulate the purpose of the study, which is to develop algorithms for carrying out measures to ensure traffic safety on the basis of economic criteria of management efficiency. Following stages of planning as the analysis of indicators of safety and identification of problems, analysis of causes of the identified problems, development of ideas objectives, setting measurable goals, checking the achievement of objectives, developing options for action achieve the goals. For each stage on the basis of methods of correlation, regression and factor analysis algorithms of their carrying out are developed. The concept of measures is developed to improve the economic efficiency of traffic safety management, depending on the method of management. With the functional approach, the main direction of the plan is to strengthen control, and with the process approach-the regulation of technological processes and training of production personnel. The authors believe that the implementation of the proposed recommendations for decision - making on traffic safety is a comprehensive preventive measure to ensure a guaranteed level of safety, which will improve the overall economic efficiency of traffic safety management in the railway company.

The processes of structure formation of hardening compositions based on hybrid binders as well as the controlled change of these processes allow obtaining concretes with increased strength and durability, for example, lightweight structural concretes on porous aggregates. Control of the structure formation of such concretes allows improving the quality and operational reliability of buildings and structures, saving binders, expanding the kinds of raw materials and solving environmental and economic issues. The results of the experiments have showed that the fineness of the hybrid binder effect the properties of the contact zone between the expanded clay aggregates and the cement matrix including the formation of calcium hydrosilicates on the surface of expanded clay gravel, which increases the adhesive strength. This leads to the increase of the quality of lightweight concrete based on expanded clay gravel.

To control the seepage in the design of an earth dam, guidelines prescribe a high proportion of fines and high homogeneity of geotechnical characteristics in the material used for the dam core. However, on many occasions there is no material of this nature near the dam placement and, from an economic or environmental point of view, it is not possible to locate and transport material with good geotechnical characteristics close to the dam. This research demonstrated the possibility of using impermeable materials in earth dam cores, as well as soils considered unsuitable according to the classic recommendations and guidelines. For an optimized design, two situations are analyzed here. First, we examined the possibility of using soil with a marked difference in grain size as the core of the dam, each with homogeneous geotechnical properties. In this case, the optimal zoning of up to three types of materials was studied to ensure adequate seepage control. Second, we examined the use of soil with great geotechnical heterogeneity, which presents high permeability dispersion. In such a case, the conditions that would allow its use were studied via the of Montecarlo analysis. By maintaining the soil’s global heterogeneity, it was possible to study an unlimited disposition of layers of different permeability. In the first situation, the results showed that the most effective zoning for decreasing seepage flow corresponded with three vertically set materials. In this design, the most optimized zoning (minimal seepage flow rates) corresponded to the most impermeable soil situated downstream when water heights were under 90% of the height of the dam core. However, for maximum water height, more optimized cases corresponded to the intermediate permeability material located downstream. In the second situation, when heterogeneous materials were used to construct the impervious element of the dams, the Montecarlo analysis indicated that the seepage flow rates were limited to sufficiently low values despite the large dispersion of material permeability. In addition, the highest maximum hydraulic gradients were observed in the lowest lifts of the dam core and for situations in which the seepage flow rates were moderate and low.