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The construction sector is one of the most material-intensive and power-consuming industries having a negative impact on the environment. The adverse environmental factors include greenhouse gas emissions, depletion of natural raw materials, extensive landfilling or dumping in the sea. In this regard, resource conservation, waste minimization, as well as the reduction of harmful substances emissions into the atmosphere, hydrosphere and soil are considered currently as the most significant environmental challenges. At the same time, the principles of material recycling and recovery are widely implemented in material production practices, as they are crucial for the construction industry. Approaches, such as life cycle assessment (LCA), that could minimize the environmental impact are being actively developed. Usually, the analysis of the environmental balance of products over the life cycle is carried out in stages, starting from the extraction of the raw materials and ending with the stage of the material recycling or processing into new products. This article provides a comparative analysis of successful European practices and analyzes in detail categories used for assessment of the environmental impact of a construction project throughout its life cycle. The larger implementation of these approaches into practice will reduce the negative impact on the environment, as well as comprehensively solve many environmental and material challenges. [ABSTRACT FROM AUTHOR]

Currently, the urgent task associated with the development and production of new, cheaper, building materials. Rocks have a reserve of free internal energy, which is determined by the method of their formation. The use of this energy reserve can reduce the work that needs to be done during the technological transformation of raw materials in the production of building materials. In this paper, it is proposed to evaluate the efficiency of using various finely dispersed systems to use as a criterion - surface activity, which shows the fraction of the potential energy reserve transferred to the surface energy during material disintegration. Assessment of the energy parameters of sedimentary rocks was carried out for the sands of developed deposits in the Arkhangelsk region. Data on the chemical composition of the samples showed that the studied sands are well suited for the preparation of concrete mix. This is due to the presence in the chemical composition of a sufficiently high amount of silica, which is able to form an active amorphous form as a result of crushing of rock. This amorphous component exhibits a pozzolanic effect when hardening concrete. In calculating the energy supply of the rock according to the principles of crystal energy, the atomization energy parameter (Ea), which estimates the thermodynamic strength of the formed bonds between atoms in crystals, was used as a criterion. Since minerals have different composition and complexity components, to compare the atomization energy, it is necessary to use the specific mass (Em) and specific volume atomization energies (EV) parameters. The latter value is the specific volume concentration of the energy of chemical bonds of a substance and can be characterized as energy density (energy density). As a result of the studies and based on the principles of crystal energy, the atomization energy of two sand deposits was calculated, amounting to 1899.53 kJ/mol for the “Krasnoflotsky-Zapad” field, for the “Kenitsa” field - 1910.72 kJ/mol. The specific values of the mass and volume energy of atomization (energy density) also have close values. So, for the “Krasnoflotsky-Zapad” field, Ev = 82.48 kJ/cm3, and for the “Kenitsa” field, Ev = 80.28 kJ/cm3. The data obtained show that, based on the existing energy classification, the sedimentary rocks under consideration can be attributed to high-energy density (Ev = 60 … 150 kJ/cm3). Acknowledgments: The reported study was funded by RFBR, project number 19-31-27001. [ABSTRACT FROM AUTHOR]

Forming a harmonious color environment is an important aspect in creating comfortable living conditions in northern cities. Currently, there is a problem of using bark waste in woodworking and rubble waste during its processing. Thus, the use of these materials, including the creation of coatings and the formation of certain colors of city buildings, is relevant. This article presents a study of the color characteristics of dry blends and composites based on environmentally friendly raw materials. The purpose of the paper is to identify patterns of changing of color characteristics by varying the composition of wood and mineral mixtures and composites based on them. In the study we used the bark from the dump of a timber processing plant. The sifting of the basalt crushing from the Myandukha deposit was used as a mineral modifying component. Dry wood-mineral compositions were obtained by mixing wood and mineral fine powders. The study revealed a darkening of the wood-mineral composite in the process of structure formation and curing. In addition, there was a shift of chromatic color characteristics towards the original finely dispersed basalt. The obtained functional dependences of the color coordinates on the composition make it possible to determine the percentage of components in the finished composite and its strength by a nondestructive method. The results of the color characteristics study of dry blends and wood-mineral composites can be the basis for obtaining blends with desired color properties in the innovative coatings production. This, in turn, will allow to form and adjust the city color environment. [ABSTRACT FROM AUTHOR]

It was found that the mechanically activated highly dispersed component based on saponite-containing waste of the diamond industry allows us to improve the physicomechanical characteristics of fine-grained concrete due to the formation of hydrosilicates of additional generation. According to the working hypothesis, the resulting new formations are submicrocrystals of the tobermorite group. The objective of this study was to identify the products of the hydration of clinker minerals with a component on the basis of the saponite-containing material in the micro- and nano-dispersed state. Differential-thermal and X-ray phase analyzes were performed to identify these products. The data obtained showed that the experimental samples with highly dispersed saponite-containing material differ from the control samples by their mineralogical composition. So in the prototype sample there are hydrate formations, the greatest intensity of which is fixed from 28 to 48 2θ, with interplanar distances 3.03; 2.76; 2.43; 2.14 Å, characterizing the lattice of tobermorite. Differential thermal analysis confirmed the obtained results. Endoeffect in the temperature range from 205 to 220 ℃, which also characterizes the presence of submicrocrystals. In continuation of the research, a comparative analysis of the microstructure of the samples was carried out. The formations of acicular and hairlike crystals - characteristic of tobermorite were shown. [ABSTRACT FROM AUTHOR]

At the present time many building of Arkhangelsk are built based on standard project. In the main these project don't take into account the negative factor of northern conditions. For such territories of cities it is necessary to create specific conditions for the formation of human habitat, including special color solutions. The study analyzes the features of the formation of a harmonious color environment and the factors of color. Also the need of using the concept of forming an urban environment based on the consideration of various factors was identified. The introduction of unified color solutions was carried out on the example of a separate region on the territory of which active development is conducted. One of the methods for creating coatings for various facade materials based on the use of environmentally friendly materials is presented. The introduction of dispersed material into the coating composition can lead to improved decorative and performance properties of the coatings. The proposed options of forming and correcting the color image of the city and the method of creating color coatings for various building materials on the basis of common natural raw materials contribute to the most qualitative management of the city's coloring. This, in turn, has a positive effect on the psycho-emotional state of a local citizen. [ABSTRACT FROM AUTHOR]

Implementation of the development program for the Northern and Arctic territories is not possible without the use of modern materials and technologies in the construction industry. One of the most common and popular building materials is the fine grained concrete, for the production of which, use chemical additives, mainly imported, improving the performance characteristics of the composite. Therefore, the actual problem is the replacement of imported components with Russian-made additives. As such an additive, technogenic raw materials can be used in the form of saponitecontaining waste from the diamond mining industry. For the production of fine-grained concrete, river sand of medium size of the “Kenitsy" deposit was used, as cementing agent - Portland cement of company “Mordovcement". The saponite-containing material extracted from the recycled water of the enrichment process of kimberlite ores was mechanically activated beforehand. Control samples of concrete and experimental (with the highly disperse additive) were prepared by standard methods. After aging for 28 days, the performance characteristics of the obtained samples (compressive strength, frost resistance and water impermeability) were determined. A highly dispersed saponite-containing material with an average particle size of 445 ± 40 nm and a specific surface of 50670 ± 10 m2 / kg was used as an additive to the concrete mixture. Determination of strength and frost-resistant characteristics showed a significant increase in these parameters in the prototypes. In addition, the introduction of a mineral supplement increases the brand's water resistance. Analysis of the microstructure of the concrete samples by scanning electron microscopy showed that (in contrast to control samples), hydrosilicates of the tobermorite group play the role of an additional binder. [ABSTRACT FROM AUTHOR]

The results of experimental research of hydration process of highly dispersed systems based on saponit-containing waste, extracted as the solid phase of the recycled water suspension kimberlite ore enrichment process of the diamond industry. Saponitcontaining sludge was dehydrated and subjected to mechanical activation on the planetary ball mill. Mechanical activation of raw material more than 60 minutes does not increase the specific surface area of samples was found. Specific surface area is achieves the maximum value of 50600 m2/kg. If we increasing the time of mechanical dispergation up to 120 minutes this parameter will be decrease due to agglomeration of particles. At the same time, average particle size of saponit-containing material will be in ranges from 445 to 517 nm. The x-ray analysis of the samples showed that the mechanical activation will help to increase the content of the active surface amorphous phase up to 40%. Adding of highly dispersed additive based on mechanic activated saponit-containing material to the composition of Portland cement after the interaction of this composition mixtures with water leads to the formation of submicrocrystals of the hydrosilicates from group of tobermorite. This fact was found by scanning electron microscopy methods. Record of absorption spectra in the infrared range of the samples was revealed of the fluctuations in the hydrosilicate groups, resulting in the following wave numbers 1440-1660 cm-1 and a broad band at 3300-3500 cm-1. This fact in agreement with the microstructural research. Thus, it is shown that the mechanoactivated saponite-containing material will be able to form the hydrosilicates of additional generation. The main conclusion of our work, based on our obtained results, allow us to use the saponite-containing waste as a potentially active mineral component in the binders compositions of hydration curing type. [ABSTRACT FROM AUTHOR]

Previous researches have shown the possibility of using organic-mineral additive based on glyoxal for injection strengthening of soils in roadbases and engineering communications. Saponite containing material was used as mineral component in the composition. Saponite containing material is a solid phase, extracted from the circulating water suspension of the kimberlite ore dressing. Modification of the sandy soil by the tailored organic-mineral additive content increases its specific cohesion up to 50 times. It was established that this effect is achieved by polymerization reaction of the organic component of the additive, while the mineral component possesses the sorption properties regulating the structure formation in the system by formatting the optimum degree of the reaction mixture saturation by a liquid phase. The aim of this research presented in this paper was to study microstructural features of clay (aluminum silicate) soils stabilized by the organic additive. As the model of aluminum silicate soil saponite containing material was used. The study of the test samples composition by X-ray diffractometry method allowed to establish the presence of the following minerals: saponite 63 %, quartz 10 % and dolomite 10 %. The content of other minerals (chlorite, hematite, calcite, apatite, etc.) is 17 %. Microstructural features of samples were investigated by scanning electron microscopy method. The obtained electronic photographs of the analyzed compositions showed the formation of a homogeneous periodic colloidal structure (PCS). It should be noted that when the organic additive is used for strengthening clay soils introduction of an additional sorbent isn't required. This is due to sorption properties of clays. In this case, the polymerization process proceeds at a constant rate uniformly throughout the volume of the analyzed soil sample. The formation of the PCS is connected with increasing dispersion interaction between the particles of the soil by synthesis of a sealing layer from the organic polymer. [ABSTRACT FROM AUTHOR]

A method for controlling the water-cement ratio of concrete in the process of hardening by introducing highly dispersed mineral additives based on saponite-containing material (SCM), extracted from kimberlitic ore waste of the Arkhangelsk region diamond mining industry (Lomonosov deposit), is suggested. The resulting relation of the material particle size and the value of its specific surface (Ssp) showed that the addition with Ssp = 50.670 m²/kg is the most efficient. The mechanism of mineral additive sorption has shown that the process of self-saturation of solids saponite-containing material with water vapor has a continuous nature (12 days). Desorption process has a different character if compared to the adsorption isotherm, i.e., there is an adsorption-desorption hysteresis. The study of SCM samples after desorption of moisture by infrared spectroscopy showed that the chemical compounds, which are present in the material, can form calcium hydrosilicates while saturated. This fact, along with the ability of modifying additive to regulate the water-cement ratio in the process of concrete hardening, contributes to a significant improvement in the physical and mechanical characteristics (strength, frost resistance) of the concrete composite. [ABSTRACT FROM AUTHOR]