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The paper is devoted to developing high-performance nanostructured concrete for 3D printing and study-ing its strength and operational characteristics. The research addresses issues related to the use of modern concrete chemistry, such as plasticisers and concrete hardening accelerators, and nanomodifica-tion by two types of nanocarbon: nanotores (Astralene) and sulphur graphene (Ugleron). The designed lightweight concrete for 3D printing has a compressive strength of about 70 MPa and 9 MPa after extru-sion at a density of about 1.55–1.6 kg/m³. Pozzolan additives from industrial waste in concrete are used, such as silica fume and oil shale ash. Microspheres, which are also industrial wastes, are used as light-weight aggregate and thixotropy regulators. As a result, lightweight, high-performance concrete for 3D printing was developed, which allows the disposal of industrial waste inside it.

This paper continues the authors' previous research on developing high-performance concretes based on low-strength aggregates. Unlike the previous work, where a low-strength crushed stone was used, the current research investigates a low-strength fine aggregate-based concrete. With modern construction chemistry in combination with pozzolan and high dispersed ground additives and nanomodification, it is possible to obtain high strength and operational characteristics concretes. The work carried out studies of three cement manufacturers for suitability in high-strength hydrotechnical concrete and phase analysis of the aggregates used in this study. Strength (7, 28, 180 days), density, waterproofness, freeze-thaw resistance of fine-grained concrete based on low-strength and high-strength aggregates were compared in the research. The final result is a concrete recipe with freeze-thaw resistance class F400, Waterproofing class W20 and compressive strength of 60.5 MPa at the age of 28 days (71.9 MPa at 180 days).

In the modern world, construction is often located in remote and hard-to-reach regions, where there are no acceptable quality aggregates for concrete. The transportation of high-quality aggregates leads to a significant increase in the cost of concrete. This paper considers the possibility of developing high-performance concretes using aggregates available in the construction region. This is possible with the use of modern achievements in the field of construction science and construction chemistry, as well as nanotechnology. The strength and mineralogical properties of gneissic granite from the Kem river bed, as well as gabbro-diabase, were investigated. During the experimental work, a high-performance nanostructured concrete based on low-strength gneissic granite was developed. The strength and operational properties of the concrete were determined. The dynamic of gain in strength of concrete at the ages of 7, 28, and 180 days was also studied. The developed binder combination can also be used to produce high-performance concretes with other low-strength aggregates.

The paper concentrates on the experimental research of basalt fibers presented at Russian market with eight samples of fibers selected for this research. Five of them are chopped basalt roving (manufactured by LUKE, Rusbazalt Inc, Kamenny Vek Ltd, Armastek), one of them is chopped polymer-basalt wire (manufactured by SK Ltd), two of them are basalt microfibers (manufactured by NTC of Applied Nanotechnologies Inc.). Each of the fibers was added to fine-grained concrete at concentrations of 0.25 vol.-%, 0.5 vol.-%, and 1 vol.-%. Changes in density, compressive strength, and flexural strength were investigated. The density of fine-grained concrete increased proportionally to the quantity of chopped basalt roving. Concrete’s density decreased proportionally with the fiber percentage when using chopped polymer-basalt wire and basalt microfiber. The highest compression strength enhancement (9.8 %) of fine-grained concrete was achieved when using fibers manufactured by SK Ltd and Kamenny Vek Ltd. The highest flexural strength enhancement was achieved when using polymer-basalt fiber manufactured by SK LLC (68.6 %) and modified basalt microfiber manufactured by NTC of Applied Nanotechnologies Inc (52.9 %).

The article gives key terms and definitions of geosynthetic materials currently used in construction, namely for reinforcement of earth foundations. Primary functions and types of geosynthetic materials are shown. Most part of the article is dedicated to the results obtained by various researchers. Reinforcement by geosynthetic materials is described for sandy and loamy soils, soil bedding, fiber soil, karsted soil, and using geosynthetics in mollisols.

Due to climate change, in the next 30-50 years, an increase in precipitation during the growing season is predicted in the Non-Chernozem zone of Russia. However, even now, traditional methods of draining poorly permeable soils in a number of cases have proved to be ineffective due to the insufficiency of operational and capital measures to accelerate the removal of surface water and the weak hydraulic connection between the arable layer and drains. The experience of operation of drainage systems in the Nonchernozem zone of Russia has shown that at large distances between channels, the removal of surface runoff is difficult. A rational solution is to reduce the distances between the conductive channels. In this case, instead of open collectors, we propose to use cavityless collectors for drainage, which do not interfere with the movement of heavy agricultural machinery. A complete analysis of the functioning of cavityless collectors has been carried out. In the part of hydrology, accounting for the increase in precipitation is discussed and a method is given for calculating the maximum average daily module of drainage flow for the early spring and summer-autumn periods. A geotechnical calculation of the settlement during the passage of a heavy general-purpose tractor of the 5th traction class K-744R1 (Kirovets) was performed. It is shown that under the design conditions, the settlements will be about 1 cm. An example of a hydraulic calculation of the reservoir with the calculation of the initial and maximum depth of the filtration flow in it is given. Hydraulic calculation is carried out according to a proven method, the theoretical foundations of which were developed by the authors in previously published articles. An important feature is that all possible filtration modes are taken into account in the hydraulic calculation: laminar, transitional and turbulent.

Analysis of recent publications describing the situation with fiber-reinforced plastic rebar is contained in the paper. The available types of composite reinforcement have a number of advantages, but also have significant drawbacks. New technical developments and fresh ideas, born thanks to the integration of sciences, make it possible to begin the creation of a technology for the production of fundamentally new types of rebar based on an inorganic (mineral) binder. New rebar will be tough and resistant to fire and high temperatures.