Effect of modifiers and mineral additives from industrial waste on the quality of aerated concrete products

The given article is devoted to research of influence of polymer modifiers and mineral additives on quality of composite aerated concrete products. When selecting the composition of composite aerated concrete local raw materials and components were used: portland cement, sand, aluminum powder, polyvinyl acetate, fly ash, post-alcoholic bard and whey of milk. Preliminary polyvinyl acetate was combined with binder mixing water at a temperature above 55ºC to obtain a readily soluble polymer emulsion. Dispersion was carried out with a rotary-pulsation apparatus at a pressure of 0.5-1.0 MPa and a rotor speed of ~1200 rpm. In the same apparatus the complex modifier was produced. The offered technology of production of a complex modifier seems to be the most effective for composite aerated concrete. It made it possible to reduce water absorption and capillary suction of composite aerated concrete by an average of 25% and 45%, respectively. Moreover, different combinations of fly ash, polymer and modifier made it possible to achieve optimal values of thermal conductivity, compressive strength and frost resistance of composite aerated concrete.

House stock forecasting based on population growth. A case of Nur-Sultan City, Kazakhstan

Since the beginning of 2020, the "Nurly Zher" housing and communal development program for 2020-2025 came into force in Kazakhstan. Within the framework of this program there are tasks of capital repair and renovation of the housing stock. The passportization of the housing stock was adopted as one of the measures to solve this problem. At the same time there are some discrepancies in the statistical data between the Committee of Statistics of the Ministry of National Economy of the RK and Local Executive Authorities with a simultaneous increase in the volume of housing construction. This article examines the volume of residential buildings commissioned in Nur-Sultan depending on changes in the population of the city. It is assumed that as the number of people in the city will increase the volume of housing stock. To understand the volume of housing in Nur-Sultan in the period of the program "Nurly Zher" in the article gives a forecast increase in commissioned housing by 62% by 2025, compared with the value at the end of 2020. Based on the data obtained it is concluded that for a more effective solution to the problem of capital repair and renovation of housing stock an alternative approach or tool is needed.

Performance of maturity method for estimation of concrete strength based on cubic specimens

To assess the condition of the structures of buildings and structures, a comprehensive analysis of the factors affecting their performance characteristics - concrete strength, protective layer, and rebar diameter, thermal conductivity and moisture content of concrete, adhesion of protective and facing coatings, frost resistance and water resistance of concrete - is required. However, with all the variety of monitored parameters the control of concrete strength has a special place because when assessing the condition of the structure the determining factor is the compliance of the actual strength of concrete to the design requirements. This paper presents studies on the determination of concrete strength based on modern technology, wireless sensor as well as instrumentation IPS. These methods are particularly effective in the case of non-linear relationships between different system parameters, as in the behavior of concrete parameters. They can also provide rapid measurements by continuously monitoring the internal condition of the reinforced concrete structure. The features of each method are given, as well as an analysis of the convergence of the results.

A multi-criteria analysis of sewer monitoring methods for locating pipe blockages and manhole overflo

This article is devoted to the aggregation of existing methods for monitoring sewerage systems into a single symbiosis, in particular methods for identifying the locations of clogged pipes and manhole overflows. Clogging of sewers is a frequent problem in large cities, entailing overfilling of manholes with sewage and disruption of the whole sewage system. Today, there are several methods for monitoring sewers: visual, acoustic and laser. Each method is represented by a wide range of devices with different characteristics and applications. The analysis identified the main technical and economic characteristics for each solution presented. Then, on the basis of the data obtained, a multi-criteria analysis was made according to several parameters: measurement accuracy, maximum diameter of the inspected pipe, type of pipe, cost. For the most objective selection, each parameter was given its own weight, and all parameters were normalized for their objective comparison. On this basis, all solutions were sorted by maximum values for each criterion, taking into account the selection by weights. As a result of the multicriteria analysis, five combinations of solutions were built, including several monitoring methods.

Features of using modified bitumen in road construction

The road industry is one of the important components of the economy. Quantitative and qualitative changes in the road industry require new technological approaches to road construction. The higher the transport-operational level of roads, the less the negative consequences of motorization are manifested. The condition of highways and their compliance with the international standards largely depends on the observance of construction technologies of road pavement, and the road pavement itself should have layers of strong, frost and temperature resistant monolithic materials which provide a long period of exploitation. The paper presents the peculiarities of the application of different types of modifiers for bitumen. It discusses their advantages and disadvantages, the importance of selecting the composition of the bituminous and mineral mixture. The use of crumb rubber as a modifier allows to realize the concept of a closed resource-saving technology of construction of roads. This approach will allow, on a technologically sound basis and taking into account the real needs of road construction materials, to restore the road network.

Modern trends in the development of the construction industry in the production of building materials

The paper describes the technology of manufacturing a construction product by vibrocompression using ash and slag waste from thermal power plants in the Pavlodar region. The task of the experimental research was to obtain a hollow wall stone based on ash and slag waste with a strength grade that is not inferior to products made according to the traditional recipe. The obtained samples with different ratios of components in the mixture were investigated for compressive strength, moisture absorption, frost resistance. It has been established that when ash and slag waste are added to the composition of the concrete mixture in an amount of up to 35 % of the mass of dry components, the strength characteristics of the hollow wall stone correspond to the selected brand

Toe drain size and slope stability of homogeneous embankment dam under rapid drawdown.

The slope stability of an embankment dam has been always a serious concern of any design team. Unfortunately, the information on the potential influence of a toe drain size on the slope stability of an embankment dam under rapid drawdown conditions is still scarce. This study investigated the potential effect of a toe drain size on the slope stability of a homogeneous embankment dam under rapid drawdown conditions. Three different sizes (5m, 10m, and 15m) of the toe drain were investigated under instantaneous (worst scenario) and 5 days (more realistic) drawdown rates with the help of numerical modeling in GeoStudio. From the results, it was observed that the pore-water pressures at the upstream face of the embankment decreased with the increase in the toe drain size, while the pore-water pressures at the downstream toe were increasing with the increase in the toe drain size. The factor of safety values were also observed to be affected by the changes in the toe drain size.

Influence of architectural and planning solutions on fire risk in public buildings

This article is devoted to the study of the influence of architectural and planning solutions on fire risk in public buildings. The calculation and assessment of fire risk was carried out on the example of one floor of a conditional office building with a free layout, where the tenant himself can change it at will. The input data for the calculation were two different layouts of the same floor, while the total square footage remained unchanged. As a calculation tool used the software package FireCat, which includes the programs Pyrosim, Pathfinder and FireRisk. The calculation took into account parameters such as the degree of fire resistance of the building, the number of rooms, the width and direction of door opening, the number of people on one floor of the building, including various mobility groups. Simulation modeling allowed to compare architectural and planning solutions for the same building and choose the best layout in terms of individual fire risk.

BIM for construction clash detection process after design stage: a case study of high residential complex in Nur-Sultan city

The construction industry is one of the most unpredictable and human-dependent sectors of production. This is due to the large flow of information during construction, which requires clear organizational activities. Traditionally established methods of communication on construction sites require modernization. That is why the concept for practitioners "Building Description System and Construction Product Modeling" was developed in 1970. The building society supported this concept and called it "Building Information Modeling" - BIM. The new wave of digital design required a strong material and technical base, the analysis of existing documentation and the creation of design tools began. The authors of the article use the highly specialized NavisWorks software to analyze possible losses as a result of combining the existing design documentation into BIM models on the example of one of the Nur-Sultan projects. The residential complex located in Nur-Sultan was chosen as the object under study. The residential apartment building was chosen because of the scale of the project and its full implementation in the BIM system. The article makes a comparative analysis on finding the intersections on the principle of combinatorics. The section of structural and space-planning solutions is checked for intersections with the sections of heating and ventilation, water supply and sewerage, then the logic is repeated. Exceptional combinations are selected to check for conflicts (collisions).

Non-destructive testing of bored piles

Quality control of bored piles is a complex operation aimed at determining possible defects in the pile shaft and the strength of the pile material made by different technologies. The presence of pile shaft defects and a decrease in the strength characteristics of the pile shaft material lead to the development of negative processes at the stage of subsequent operation of the building and structure. It is known that the bearing capacity of the pile material should not be less than the bearing capacity of the ground. Consequently, it is necessary to strictly observe the quality of the concrete of the design strength values to ensure the reliability of the designed building concerning the service life. Nowadays different methods of nondestructive testing such as pile integrity test, cross-hole sonic logging. The paper presents a discussion of the advantages and disadvantages of each of them, experimental data also are given