Compositions and technology for obtaining a photocatalytic composite material (PCM) by deposition of titanium dioxide particles synthesized by the sol–gel method on a silica support of various types (microsilica, gaize and diatomite) have been developed. The properties (chemical and mineral composition, dispersion, specific surface area, porosity, ζ-potential, acid–base properties, and microstructure) of microsilica, gaize and diatomite were studied to assess the effectiveness of using a photocatalytic agent as a carrier. In terms of specific viscosity (η_sp = 45), the concentration of the precursor (tetrabutoxytitanium—TBT) is set at 22 vol. % in a solvent (ethanol), at which it is possible to obtain the maximum amount of dissolved film oligomer without the formation of an aggregate-like precipitate. Modification of the reaction mixture (precursor: ethanol = 1:3) by replacing part of the solvent with a Span-60 surfactant/TBT = 1–1.1 made it possible to obtain polydisperse titanium dioxide particles with peak sizes of 43 nm and 690 nm according to laser granulometry data. Taking into account the interaction of titanium complexes with the surface of a silica support, a phenomenological model of the processes of structure formation of a photocatalytic composite material is proposed. By the value of the decomposition of rhodamine B, the photocatalytic activity of the developed composite materials was determined: PCM based on diatomite—86%; PCM based on microsilica—85%; PCM based on gaize—57%.

This paper describes the technology and properties of autoclaved foam concrete taking into account practical experience and laboratory studies. The results of study of raw materials and analysis of structure and properties of foam-concrete before and after autoclave treatment are basic in this work. Experimental studies of structure and properties of foam concrete are carried out according to up-to-date methods and equipment on the base of the shared knowledge centers. Results of experimental studies give a deep understanding of properties of raw materials, possible changes and new formations in inner layers of porous material providing the improvement of constructional and operational properties of autoclaved foam concrete. Principal directions of technology enhancement as well as developing of production of autoclave foam concretes under cold-weather conditions in Russia climate are justified.

The sustainable development of the country's construction industry in the context of limited availability of resources involves the implementation of eco-oriented principles for assessing all stages of the life cycle into the life cycle management of construction projects, as well as the search for new organizational and technological solutions in construction. This in turn implies a shift towards green, low-carbon building, as well as improved tools for quantifying, monitoring and managing the carbon footprint of buildings. The intensive growth of complex development and the increased attention to global climate change make the issues of reducing the carbon impact that occurs during construction and pre-construction stages an urgent and promising area of research. In accordance with the Strategy for the Socio-Economic Development of Russia with Low Greenhouse Gas Emissions until 2050, the regulation and reduction of carbon impact and, as a result, the transition to low-carbon construction depends, first of all, on the scientific study of the issue.The authors propose recommendations for improving the tools for assessing the carbon impact of construction projects at the pre-operational stages of their life cycle, which are applicable in the formation of an effective state order for the creation of construction products that meet modern conditions of environmental friendliness and carbon neutrality. This can be effective in creating an institution of extended responsibility for construction participants, including a mechanism for certification of low-carbon building products.

In this research, a phase formation in CaO–SiO₂–Al₂O₃–H₂O binding system under hydrothermal conditions was studied. The novelty of this article lies in the quantitative full-profile X-ray diffraction (XRD) analysis used to determine kinetics of mineral formation in the binder system “lime–granite mineral modifier (GMM)”. The formation of a polymineral system is described in detail, as well as quantitative relationships between mineral composition of newly formed phases and the binding mixture ratios were determined. Phenomenological model of mineral formation in a “lime–GMM” system under hydrothermal conditions was proposed. The results obtained allow the demonstration of this binding system as a binder that is characterized by superposition of hydration and geopolymerization. The properties (strength, density, water absorption, porosity) of compressed autoclave-hardened materials with the addition of a granite modifier introduced instead of part of the sand as an aggregate have been studied. The maximum increase in strength (more than 50%) is observed at a modifier content of 15%. This is due to the formation of a rational composition of neoplasms, the compaction of the structure of the pressed products and the optimization of their pore space, which is confirmed by the data of X-ray diffraction analysis, scanning electron microscopy and the method of gas adsorption.

Silica raw materials are widely used in many industries, especially in the manufacture of building materials. Among all rocks with rockforming silica minerals, chemogenic and biogenic sedimentary rocks are highly demanded as active (pozzolanic) mineral additives for composite binders. Raw materials containing amorphous silica are used to obtain composites of the TiO2–SiO2 system with high photocatalytic activity. High sorption properties of silica raw materials are critical in the process of photocatalysis, since these indirectly affect the interaction between respective organic compounds and the photocatalyst surface for their oxidation to the safe compounds of H2O and CO2. Therefore, it seems promising to use silica sedimentary rocks as a photocatalyst carrier in the manufacture of photocatalytic composite materials (PCM) used in cement concrete. This work covers the study of the DIASIL diatomite fine powder and gaize of the Alekseevskoe deposit, as well as PCM obtained on their basis, by the sol-gel deposition of the photocatalytic agent at various precursor/solvent ratios. Preparation of the gaize feed material required disintegration in a jaw crusher and a ball mill to the particle size of –100 μm. The results for the evaluation of the surface acidic properties, the degree of CaO absorption from the lime solution, and the photocatalytic activity of the PCMs synthesized indicate the high efficiency of using the silica raw material studied as a substrate for the TiO2 photocatalyst.The study was carried out with a grant from the Russian Science Foundation (project No. 19-19-00263) using equipment based on the High Technology Center of BSTU named after V. G. Shukhov.