More than 1.5 billion tonnes of ash and slag waste from thermal power plants have been accumulated in the RF. The most promising direction of reuse is construction and repair of roads. The most material-intensive direction is the construction of earth bed. The aim of the study is to expand the practice of using ash and slag mixtures from thermal power plants for the construction of roadbeds in continental and polar climate. In order to achieve the goal set in the work the ash and slag mixture from different ash dumps of Irkutsk region was sampled. Ash and slag wastes can be considered as technogenic soils and classified according to GOST 25100 as gravelly sands and dusty sands. Ash and slag mixtures do not possess cohesion, have low values of internal friction angle, high porosity of particles and low specific weight, and small frost heave deformation. To evaluate the efficiency of ash and slag mixtures application in the structures of the roadbed of roads the design and construction of the roadway and the roadbed on the section of the road in the Irkutsk region was carried out. The technology of works on construction of earth bed layers from ash and slag mixtures is similar to the technology of erection of layers from soils. The constructed construction of road with earth bed from ash and slag mixtures has operational characteristics not lower than the construction of the adjacent road section with earth bed from local soils. Ash and slag mixtures can be used for construction of earth bed layers practically without restrictions.

The development of new types of environmentally friendly and cost-effective building materials is currently a relevant topic and is actively developing throughout the world. In modern construction materials science, the most popular direction is the development of new concrete compositions using waste of various origins. The objective of this study is to develop new compositions of foam concrete using local waste from the fuel and energy complex and plant natural fibers. To determine the optimal amount of the modifying additive fly ash (FA), 7 experimental concrete compositions with different percentages of cement replacement by FA were made. The content was established as optimal. Foam concrete with 15% FA has the lowest density of 1075 kg/m3 and a minimum thermal conductivity coefficient of 0.248 W/m × °C, as well as increases in compressive and bending strength of 23.3% and 21.7%, respectively. The effect of coconut fiber (CF) was assessed on the composition of foam concrete modified with the optimal amount of FA 15%. The optimal dosage of CF was 0.6%. As a result of FA modification and CF dispersed reinforcement, a complex effect was obtained. The increase in compressive and bending strength was 30.14% and 72.83%, respectively, compared to conventional foam concrete. The density and thermal conductivity coefficient decreased by 9.8% and 8.34%, respectively. The results obtained during the experimental studies prove the effectiveness of the proposed formulation solutions and allow obtaining an energy-efficient foam concrete composite with improved characteristics.

The concept of the sustainable development of the world economy is currently aimed at achieving carbon neutrality, and this is due to the global warming of the planet. Energy and construction make a significant contribution to the release of carbon emissions into the environment and atmosphere. According to statistics, simply burning one ton of Portland cement clinker provokes the release of at least half a ton of carbon dioxide. In this study, the prepared samples were subjected to electron diffraction studies, as well as the X-ray phase analysis of the zone (XRF) using an ARLX’TRA diffractometer. Studies of macro- and microstructures were carried out using a Quanta 3D 200i scanning microscope. The obtained spectra were processed using EDAX TEAM software. The study of the microstructure of the samples showed that the bulk of the heterogeneous systems consisted of volumetric aggregates and intergrowths, i.e., small accumulations on their surfaces with pronounced cleavage, features of the microstructure indicating mineral formation processes. Therefore, the development of low-carbon construction models will make it possible to make a contribution and open an effective path to the implementation of climate policy through the rational use of natural resources and the involvement of industrial waste and nature-like technologies in the production process. In this regard, one of the options for solving the identified problems is to revise existing technologies and develop low-carbon, low-clinker binders using industrial waste and substandard raw materials.

Modern materials science is aimed towards abandoning Portland cement in the production of building materials. The scientific novelty of this study lies in its being the first time a comprehensive study of the structure formation of alkali-activated materials (AAM) based on thermally treated marl and Na₂SiO₃ is carried out. The tasks for achieving this goal were to characterize the thermally treated marl as a new binder, and to comprehensively research the microstructure, fresh, physical, and mechanical properties of the AAM based on the binder. Received active particles of marl with a smaller size than Portland cement have a specific surface area of 580–590 m²/kg. The mineral composition of heat-treated marl is characterized by calcium silicates, which guarantee good binding properties. The results of X-ray diffraction analysis of the samples based on the clinker-free binder of alkaline activation using opoka-like marl confirmed the presence of calcite, quartz, and feldspar close to albite, micas, and zeolites. The obtained products of the chemical interaction of the components of the binder confirm the effectiveness of the newly developed AAM. As a result of comparing several binders, it was found that the binder “thermally treated marl—Na₂SiO₃” is the most effective, since for specimens based on it, a maximum compressive strength of 42.6 MPa, a flexural strength of 4.6 MPa, and minimum setting time were obtained (start 26 min, end 32 min) as well as a water absorption of 10.2 wt.%. The research results will be of interest to specialists in the construction industry, since the proposed recipes for clinker-free cements are an alternative to expensive and energy-intensive Portland cement and provide the creation of strong and durable concrete and reinforced concrete composites.

Objectives Development of compositions filled with binders based on recycled materials for monolithic high-strength concrete.Method The research methods adopted in the work are based on the theoretical principles and laws of designing and optimizing polydisperse multicomponent systems, the phase and structure formation of clinker minerals, the logic of mathematical calculations, the technological features of the structure formation of composite masses, the theoretical principles of controlling the rheological processes of mixes. All experimental data presented in the work were obtained according to the methods of current regulatory documents (GOST, recommendations, etc.).Result The paper provides an analysis of the experience of using recycled materials in the form of products of demolition of buildings and structures, the technology for producing secondary raw materials for concrete on their basis. Formulations filled with binders with an activity of 60-71 MPa with finely dispersed mineral fillers from concrete scrap and brick combat with a ratio of 70:30%, respectively, were developed and investigated.Conclusion The optimal formulations of highly mobile concrete mixtures were designed using local natural and technogenic raw materials with a grade of P5 cone sediment and persistence for more than 8 hours to obtain high-strength classes of compressive strength up to B60-B80 with unique operational properties.

The cement industry is recognized as an environmental nuisance, and so there is a need to not only minimizes the consumption of cement, but also to completely recycle the waste of the cement industry. This paper’s originality lies in the fact that, for the first time, a comprehensive study of the structure formation of alkali-activated materials (AAM) based on aspiration dust and clinker dust has been carried out. The tasks for achieving this goal were to characterize cement production waste as a new binder and comprehensively research the microstructure, fresh, physical, and mechanical properties of alkali-activated material based on a cement-free binder. Grains of cement production waste are represented by coarse volumetric particles with pronounced cleavage, and a clear presence of minerals is observed. The mineral composition of cement production waste is characterized by calcium silicates, which guarantee good binding properties. The results of the X-ray diffraction analysis of the samples (based on the alkaline-activated cement-free binder using clinker dust and aspiration dust) confirmed the presence of calcite, quartz, feldspar close to albite, micas, and zeolites. The obtained products of the chemical interaction of the binder components confirm the effectiveness of the newly developed AAM. As a result of comparing several binders, it was found that the binder based on aspiration dust with Na₂SiO₃ and Na₂SiF₆ was the most effective, since, for specimens based on it, a density of 1.8 g/cm³, maximum compressive strength of 50.7 MPa, flexural strength of 5.6 MPa, minimum setting time (starting at 24 min and ending at 36 min), and water absorption of 12.8 wt. % were obtained. The research results will be of interest to specialists in the construction industry since the proposed recipes for eco-friendly, alkali-activated materials are an alternative to expensive and energy-intensive Portland cement, and they provide for the creation of strong and durable concrete and reinforced concrete composites.