Introduction. The process of ensuring the operability of transport and technological machines (TTM) presupposes regular checking of its technical condition by diagnosing various units, assemblies and systems, including electronic systems for monitoring and controlling the functioning of the internal combustion engine (ICE). However, in real operation, there may arise situations in which conducting operational diagnostics of power plants is problematic. Such situations contain, for example, the work of transport and technological machines in hard-to-reach poorly developed regions with the absence of maintenance centers nearby.

Materials and methods. One of the key evolution areas of modern power plants is the introduction of automated control and monitoring systems based on the use of electronic and microprocessor technologies. Such systems significantly increase the efficiency of the engine, however, due to their complexity and design features, the number of potentially possible internal combustion engine malfunctions increases, which requires the development and implementation of special approaches to their diagnosis and maintenance. One of the solutions to the problem of electronic control systems’ operational diagnostics of an internal combustion engine is to assess the operational condition by the acoustic noise it produces, recorded with the use of a portable device, processed and analyzed by specialized software. The advantage of this method is in its simplicity and the possibility of conducting diagnostics in the field, directly at places where the machines are being used. The purpose of this study was an experimental assessment of the fundamental possibility of identifying malfunctions of electronic control systems of an internal combustion engine by comparing acoustic characteristics in normal operation and in conditions of limited functionality caused by failures in electronic control systems of its operation. A gasoline engine was used as an object of research, which is an element of the GNFA training stand designed to study electronic control systems for internal combustion engines. During the study, various possible malfunctions of the electronic control systems of the engine were set at the stand, causing its operation to switch to the mode of limited functionality, and noise parameters were measured and analyzed in comparison with the parameters of a serviceable internal combustion engine.

Results. Various kinds of malfunctions of the electronic control systems of the internal combustion engine have been analyzed and some have been identified in which the engine switches to a mode of limited functionality while maintaining its operability, i.e. it operates intermittently, with reduced power, increased fuel consumption, etc. A comparative analysis of the acoustic parameters of a serviceable engine in the presence of such malfunctions, followed by spectral decomposition to substantiate the rules for their identification.

Discussions and conclusions. The results of the conducted research can serve as a basis for the development of the method for rapid acoustic diagnostics of electronic control systems for power plants with the use of mobile portable equipment.

Introduction. The process of asphalt concrete compaction is one of the most important in the construction of road surfaces. Traditional compaction methods include the impact of a row of rollers with smooth or vibrating drums. As an alternative, a variant for continuous compaction in the form of combined compaction equipment is proposed. The main working element of which is a drum with an offset axis of rotation, which has a multiple effect on the compacted material. This process is a complex, therefore, the article considers the hypothesis of substantiating the feasibility of using an elastic-deformable belt in combined compaction equipment for asphalt concrete mixtures.

Materials and methods. A laboratory stand was designed to conduct experimental studies, and a methodology for carrying out experiments demonstrating the effect of the presence of an elastically deformable belt element on the quality of the finished coating was developed. The size of the prism of the material ejection in front of the working element was chosen as a quality indicator, the value of which affects the uniformity of compaction and the integrity of the material structure.

Results. The data obtained by the experiments were recorded, systematized and analyzed for subsequent study, which showed the following: in the case of the presence of a layer between the working element and the compacted material - elastically deformable belt element, the size of the material prism in front of the roller is noticeably reduced, which shows an increase in the quality of the finished coating. Conclusion. As a result of the survey, the hypothesis about the necessity of the elastically deformable belt element in the design of combined compaction equipment for improving the quality of the finished asphalt concrete road surface was proven.

Introduction. The article presents an overview of modern diagnostic methods for mobile machines. The directions of diagnosis are outlined: with the applications of algorithms based on the use of a complex of controllers designed to collect and store up-to-date diagnostic information; with the help of artificial intelligence allowing to perform stepby-step diagnostics on current information about the speed of hydraulic motors, pressure and fluid velocity. The article also demonstrates the ways for using parametric statistical methods that are possible to determine the state of the working fluid and predict the state of various hydraulic drive units; filter condition indicators for assessing the wear degree of gear pumps; a system of indicators demonstrating unconsumed residual resource of hydraulic drive elements.

Materials and Methods. The authors propose to use the Bernoulli equation to determine the velocity and piezometric heads in selected sections of the hydraulic drive in order to construct a digital model in the form of a hydraulic slope curve. It is noted that for hydraulic systems equipped with hydraulic motors, it is possible to obtain different operating modes of hydraulic sections at minimum and maximum pump speeds, which makes it capable to analyze the operation of the hydraulic system at pressures that vary over a wide range. The digital model is built on the basis of known dependencies, which theoretically allow us to determine the velocity and piezometric pressures in different parts of the hydraulic system.

Results. The application of this digital model in various areas, during maintenance of the hydraulic drive and a comparison of the measured values in the sections of the hydraulic system with the theoretical ones will make it possible to establish its serviceability or predict failure.

Discussions and Conclusions. The proposed approach will allow to carry out repairs in a timely manner and eliminate sudden equipment failure.

Introduction. A characteristic feature of works on constructing the underground part of buildings or structures in the conditions of St. Petersburg is the significant thickness of weak clay soils. Such soils require gentle impact during various technological operations. The equipment used for constructing pile foundations can significantly affect the soil base and buildings in the area. The degree of construction machine impact is detected on completing construction works.

Materials and methods. The article presents the main types of construction machines used for the construction of pile foundations in the conditions of St. Petersburg. A comparative analysis of technological parameters, advantages and disadvantages of various equipment has been performed. The engineering and geological conditions typical of St. Petersburg and the restrictions they impose on technologies for building pile foundations have been shown.

Results. Examples of technological impact of various pile building methods on basements of the surrounding buildings and their structures in the conditions of St. Petersburg are given. A brief overview of soil conditions, machines and mechanisms, as well as potential risks of emergency situations is given.

Discussion and conclusions. Conclusions have been made on most gentle methods of constructing pile foundations in conditions of weak clay soils and cramped urban development. Recommendations are given about the possibility of predicting the technological impact when constructing piles using numerical methods.

Introduction. The article presents the results of research of technical parameters reflecting the use of single-bucket hydraulic excavators by time. The dependencies given in normative documents necessary for processing of the obtained data are analyzed. The existing systems of data collection from the on-board computer of single-bucket excavator were analyzed. The excavator manufactured by Hitachi (Japan) was chosen as the machine under study.

Methods and materials. To determine the utilization rates by time (excluding idling and movement within the object), idling, the data collection methodology was described. Excel and Statistica software was used to process the obtained database. The description of histograms formed with the help of on-board computer software was performed. A number of formulas allowing to estimate the efficiency of excavator operation without taking into account time losses for idling were proposed.

Results. The obtained sample was processed with the help of Statistica software. Time utilization factor of singlebucket excavator is described by beta-distribution, idling factor by Weibull distribution. The parameters of distribution laws of time utilization and idling coefficients (mathematical expectation, Student’s coefficient) were also obtained. Numerical characteristics of the data samples were obtained according to the dependencies proposed by the authors. It was found that the average share of idling is 21% during the shift, and its duration is about 2 hours.

Conclusion. The obtained values of the coefficients characterizing the intensity of operation can be used by operating enterprises in planning the rate of construction of facilities. It was concluded that the obtained data differ from the values described in normative documents, and their implementation will allow better planning of the process of work production.

Introduction. The article substantiates the relevance of scientific developments aimed at ensuring the safety of live poultry in the process of its transportation to slaughter by road transport. The concept of safety of live cargo transportation is explained in accordance with the current legislation. In calculations the concept of effective temperature as a correct measure of the studied parameter is used. The dependence of broiler chicken lost in the process of transportation on the duration of their delivery to the slaughterhouse at different effective ambient temperature is established. The non-uniformity of temperature distribution inside the body of a moving poultry car in the warm season has been proved, that allows to develop recommendations on improving the safety of transported poultry.

Materials and methods. Analysis of regulatory and legal, scientific literature, statistical, technical and economic analysis of motor transport service of poultry complex, instrumental measurements.

Results. Possessing scientific novelty: the dependence of the number of broiler chickens lost in the process of transportation on the duration of their delivery to the slaughterhouse at different effective temperature of the environment, as well as the graph of temperature deviations inside the body of the poultry truck from the effective temperature of the environment in the warm season; - having practical significance: the amount of damage to the growing livestock by the loss of cargo due to delays in the movement of the poultry truck.

Discussion and conclusions. The set tasks have been executed completely, resulting in received methodical recommendations on increasing the safety of live poultry during transportation by automobile transport. Implementation of the proposed recommendations will ensure decrease of poultry losses during transportation to slaughter by 15%.

Introduction. Traction and power parameter’s monitoring of wheeled vehicles are often performed on roller stands. The accuracy of determining the traction force in the contact patch of the elastic tire of an automobile wheel with the cylindrical surface of the rollers depends on many factors. With the specified characteristics of the stands, the working air pressure in the tires, the load applied on the wheels and the residual tread height of the tires most significantly affect the results of measuring forces. These parameters have a considerable impact on the speed and force losses of power in tires.

To take into account the force and speed components of power losses in wheel tires while testing cars, a technique was proposed that allows to reduce their impact on test results considerably, and measurement results obtained by testing cars on the roller stand and in road conditions were presented.

Materials and methods. To determine the force component of losses in a tire, the experimental studies were conducted to define the rolling resistance coefficient of tires on two kinematically unrelated rollers of the power stand. The role of the speed component of losses was specified by determining the rolling radius of the wheel on the running drums of the stand and evaluating its effect on the measurement results of traction and power parameters of the car.

Results and discussion. The result of the conducted research is the development of a new methodology for testing traction and power parameters of vehicles with all-wheel drive and single-axle drive, which allows to take into account the influence of air pressure and the residual height of the tire tread on the measured values of traction force on the wheels.

Conclusion. According to the proposed method for measuring traction forces on the driving wheels of M1 category cars on roller stands, the optimal value in terms of the effect of force and speed losses on the results of measuring traction parameters is the air pressure in tire that is not least then 150% of the values set by the manufacturer.

Introduction. In practice, it is required to obtain mixtures both of equal workability, estimated by standard technical indicators (cone sediment, spreading, etc.) and of different rheological characteristics. Diluent additives effectively reduce the yield strength and viscosity, however, the effect of mineral additives in combination with organic surfactants on the rheological parameters of cement dispersions has been poorly studied. The paper is devoted to the study of this issue.

Research methods. Finely dispersed quartz (S_ud=340 m²/kg) and marble (S_ud=320 m²/kg) obtained by grinding in a laboratory mill were used; binder CEM I 42.5 H of Oskolcement CJSC (t_n.cw=230 min; НГ=26 %, C3S=61,59 %, C2S=14,2 %, C3A=6,83 %, C4AF=3,73 %); superplasticizer Polyplast SP-1, hyperplasticizer Sunbo 2021. Rheological parameters of cement dispersions were determined at low shear rate gradients έ up to 25 sec^-1, which makes it possible to ensure the similarity of flow in laboratory and real conditions.

Results. It has been established that pure and mixed cement dispersions without diluent additives are rheologically complex bodies with the highest shear stress and plastic viscosity. Mineral modifiers in combination with plasticizing additives effectively reduce plastic viscosity and shear stress, and their flow transitions to the Newtonian fluid regime with a viscosity independent of the shear rate gradient. Rheological parameters without additional mixed cement dispersions depended on the type of mineral filler. At the same time, with the introduction of diluent additives, dosages and the chemical base of additives have a predominant effect on rheological parameters.

Conclusion. Mixed cement-marble and cement-quartz dispersions with the introduction of diluting additives are characterized by higher fluidity than cement dispersions. The introduction of plasticizing additives at certain dosages makes it possible to completely remove non-linearity, and the use of mineral fillers enhances the effectiveness of surfactants.

Introduction. According to the Russian Ministry of Natural Resources, the country currently generates 22-25 million tons of fly ash and slag waste per year, and up to 10% is disposed. By the Government Order of the Russian Federation No. 1557-p dated June 15, 2022, the “Comprehensive Plan for increasing the volume of ash and slag waste disposal of hazard class V” was approved. Ekibastuz coals are the highest ash fuel coals used at thermal power plants in the Russian Federation. The properties of fly ash and ash slags depend on the type of fuel being burned - its mineral part (overburden), as well as other technological features of the processes of preparation, combustion, capture and disposal of materials. That is why the properties of these materials should be considered in relation to a specific fuel.

Methods and materials. The object of the study was fly ash and ash slag obtained by the combustion of Ekibastuz coals at Russian thermal power plants. With the use of physical and chemical analysis methods, the chemical and mineralogical composition was studied, the physical properties and environmental parameters of these materials were determined.

Results. As a result of the conducted research, the chemical, mineralogical and phase composition of fly ash and ash slag of Ekibastuz coals have been established. The specific features of physical properties have been identified and the causes of their formation have been identified. Specified data on the environmental characteristics of fly ash and ash slag have been obtained.

Conclusion. Ekibastuz coals are characterized by the highest ash content among all fuel coals, reaching 45%, which necessitates the active involvement of ash and slag wastes in the country’s construction industry. A number of specific properties must be taken into account for the effective use of fly ash and ash slag formed during the combustion of these coals. The fly ash of Ekibastuz coals, characterized by a superacid chemical composition, does not demostrate the properties inherent in mineral binders. However, the fly ash obtained by dry capture has the ability to interact with hydrolysis products of mineral binders and be involved in hydration processes, which indicates its potential activity in building composites. Kaolinite, which dominates the mineralogical composition of the Ekibastuz coal rock with a limited presence of fluxes, necessitates high temperatures for modification and thermal activation of the mineral component. This feature has a direct effect on the phase composition of the formed fly ash and ash slag, determining their characteristics and properties. The dissociation of minerals in finely ground coal stimulates the formation of both closed and open microporosity in ash particles. This process leads to a significant increase in their specific surface area and chemical activity, determining the physical properties of fly ash and ash slag. The slag component from the burning of Ekibastuz coals is heated only to the sintering stage, but not melting. This determines the reduced density and mechanical properties of the ash slag. Ekibastuz coals are characterized by a high content of fusain in the organic part. The petrographic characteristics of this organic mass determine the increased resistance of carbonaceous residues to aggressive influences. The radioactivity of the Ekibustuz fly ash and ash slag does not exceed the permissible limit for classifying them to the 1-st hazard class according to the specific effective activity of the latter. Ekibastuz ash and slag wastes have been assigned the V-th hazard class for the environment, defining it as practically non-hazardous waste.

Introduction. Flooding of built-up and developing city areas with groundwater is an unfavorable process in our country and around the world. The groundwater level (GWL) rises to the surface of the earth. The consequences of increasing the groundwater level are dangerous for humans and the environment. Drainage of urban areas leads to a decrease in groundwater level. Drainage systems are an active protection against flooding with groundwater. Climate affects the processes of flooding and drainage in urban construction. This influence is taken into account too little in the current building codes and calculation methods for designers, builders and employees of urban services. A lot of materials have been accumulated that require scientific publication due to their relevance for further improvement ways to withstand flooding of urban and populated areas with groundwater with climate considering. Ineffective situations of extensive protection against sudden onset flooding are observed all over the world every year. It is necessary to strengthen the role of scientific approaches in making the choice of appropriate measures to keep save against flooding. Paying attention to the climate influence on flooding and drainage processes in urban construction can make a significant contribution in this direction.

Methods and materials. The urban man-made environment differs considerably from the natural before construction, most of all in flooding and drainage of territories, buildings and structures. Therefore, the theory of filtration in urban construction requires improvement of the methodology of forecasting, calculating and modeling flooding and drainage, especially paining attention to the climate of cities, which is still almost not taken into account in the development of protective measures. This paper presents new ideas and their implementation on the stated research theme. This opens a new direction of scientific methodology related to flood protection in urban construction with the consideration of climate influence. New ideas cannot be implemented in one article, since the problem is very extensive. Therefore, in the future, it is expected that other scientific studies will be published on this current theme, planned as a direction of promising and relevant scientific research.

Discussion. In the course of the study, the characteristics of the city climate that can affect the processes of flooding and drainage of groundwater in built-up and developing city areas has been considered.

The impact of the Sun is very significant. Sun rays, passing through the atmosphere, affect the groundwater regime. The share of solar energy is several times of magnitude greater than the influence of the temperature gradient coming from the depths of the Earth to the earth's surface. The impact of sunlight is expressed in the form of solar radiation. In this case, the albedo of the irradiated surfaces has an effect. Urban development creates significant shading of the soil surface with a subsequent decrease in evaporation and an increase in moisture infiltration to groundwater. The wind regime of the development changes. This has been taken into account in the presented methodology of the article, the necessary dependencies and examples of calculating the reduction of water evaporation from the soils of the foundations of buildings and structures are given. New experimental measurements on the theme of the study, as well as author’s innovative devices and instruments have been considered.

Conclusion. Thus, a new direction of scientific methodology related to protection from flooding in urban construction has been discovered, taking into account the climate change of the technogenic environment of the built-up and developing city areas. The presented work should be considered as a pioneering article, giving in the first approximation a new methodology for the considering the influence of climate on the processes of flooding and drainage in urban construction. Therefore, in the future, it is expected that other scientific works will be published on this acute topic, planned in the direction of promising and relevant scientific research.

Introduction. Due to the ever-increasing demands for the quality and reliability of concrete structures for tunnel construction, the task is to develop modified concretes with improved performance characteristics.

Materials and methods. This study examines issues related to the modification of the composition of heavyweight concrete with a complex chemical additive, which includes the Sunbo PC-1021 superplasticizer, the water-soluble polymer additive Polidon-A together with activated metakaolin. It has been established that the process of chemical activation of metakaolin particles has not been sufficiently studied. In this regard, the presented studies, which consist of finding solutions to improve performance characteristics due to the process of its preliminary treatment with an alkaline medium pH = 10 together with a micro-reinforcing component (wollastonite), are relevant.

Results. A positive effect of complex modification on the properties of heavy concrete was established by reducing the content of binder (cement) and replacing it with metakaolin, pre-activated in an alkaline medium with pH = 10 with a modifier and wollastonite, which improves the strength and hydrophysical characteristics: compressive strength at the age of 28 days was 68.6 MPa compared to the control composition - 39.4 MPa; water absorption - 2.4%; water resistance grade - W14.

Discussion and conclusions. The problem of obtaining effective concrete for tunnel structures with improved performance properties can be solved by modifying the binder in the composition with activated metakaolin together with a complex modifier of the mixture (PC + 5% MTK_akt + 0.4% SP + 0.3% Polidon-A + 2% wollastonite). The proposed composition makes it possible to manufacture reinforced concrete structures for tunnels with specified characteristics in production conditions, operating under conditions of increased load and aggressive environment.