Marina O. Dudareva

Introduction. Invasive plant species invade existing ecosystems, displace native flora species, causing damage to the environment and agriculture. One way to control the spread of invasive species is to use them to create composite materials and additives for building materials. The purpose of the review is a theoretical study and establishment of the possibility of obtaining extracts from plant mass of invasive plants and the development of environmentally friendly biocidal compounds of natural origin to prevent the biological destruction of building materials. Methods. This paper studies Russian and foreign literature concerning the chemical composition of plant extracts, the biological activity of secondary metabolites present, as well as the development of environmentally friendly, non-toxic compounds for humans that are effective for preventing biological deterioration of building materials. Results. The possibility of using extracts from invasive plants growing in the Russian Federation and obtaining modifying additives for building materials based on them is considered. According to data present-ed in Russian and foreign literature, plants such as Heracléum sosnowski, Ambrósia artemisiifolia, Solidago canadensis, Reynoutria japonica and Lupinus polyphyllus contain biologically active compounds: phenols, polyphenols, tannins, flavonoids saponins, anthraquinones, and polysaccharides that inhibit the development of bacteria, viruses, and microscopic mold fungi, suspending their growth and reproduction. Conclusions: The presented review and analysis of literary sources indicate the possibility of using extracts from plant mass of invasive plants as biocidal modifiers for building materials.

Nowadays, mortars are building materials with various properties that can be achieved through the careful selection of components and the introduction of different modifying additives. An additive based on the TiO₂–Bi₂O₃ oxide system can be considered a modifying component with photocatalytic and biocidal properties capable of decomposing organic pollutants, viruses, bacteria, and fungal spores. The purpose of the work was to obtain cement compositions containing the additive, study their physical and mechanical properties, evaluate their photocatalytic activity in accordance with the UNI 11259-2016 standard, and assess their resistance to mold fouling. In this study, samples of cement–sand plaster with the TiO₂–Bi₂O₃ additive synthesized via citrate-based technology at 1.7 and 5.0 wt.% were prepared, and their physical, mechanical, photocatalytic, and biocidal properties were examined. As a result, the authors identified photocatalytic activity in both the UV and visible spectra, achieving 69% after 26 hours of UV irradiation. The samples demonstrated 100% resistance to mold fouling. The compressive strength of the modified samples increased by 32.0–39.0%; bending strength by 33–38.0%; and adhesion strength to the base by 60–70%. The cost calculation also confirmed the feasibility of introducing the additive at 1.7 wt.% into the cement composition. The resulting cement material formula can be recommended for designing fungi-resistant, self-cleaning plasters.

In Russia, a rapid growth in construction sphere is observed, which by the end of 2023 amounted to 110 million 438.5 thousand square meters. m. housing, which is 7.5% more than a year earlier. The construction process is carried out using high-tech innovative building materials with unique properties, durability, friendly to the environment and humans. Howev-er, in addition to the advantages, modern building materials should be financially accessible, their application should not lead to an unjustified increase in the cost of the project. In this article, the authors analyze the economic efficiency of using a ployfunctional additive based on the TiO2-Bi2O3 oxide system in order to create concrete mixtures, self-cleaning cement plasters, grout solutions for ceramic tile resistant to fouling by microscopic mold fungi. As a result of the research, the authors concluded that a polyfunctional additive based on the TiO2-Bi2O3 oxide system can be used to obtain a wide range of building materials.

The current stage of the construction industry development implies increased requirements for building materials to maintain and improve global environmental processes. The understanding by ecologists globally of the danger of anthropogenic impact on the global environment has been reflected in the formulation of Sustainable Development Goals (SDGs). Thus, scientists and engineers are turning to safe plant-based raw materials as innovative building materials. Of particular interest for practice is the use of Reynoutria sachalinensis, which may exhibit biocidal properties. The purpose of this study was to obtain a gypsum stone modified with an extract from the green mass of R. sachalinensis, as resistant coating to fouling by microscopic fungi. The results indicated 10% decrease in the required water addition to gypsum paste when using plant extract, a slowdown of the initial and final setting time of the modified gypsum paste samples compared to the control samples by 6 and 7 min, respectively, and a slight decrease in bending and compressive strengths of the samples of 12.5% and 6%. The 100% resistance of the modified samples to fouling by microscopic mould fungi was also revealed.

The development of modern building materials science involves the process of designing innovative materials that exhibit unique characteristics, such as energy efficiency, environmental friendliness, self-healing ability, and photocatalytic properties. This can be achieved by modifying cement with nano- and fine-dispersed additives that can give the material new properties. Such additives include a number of compounds based on the TiO₂-Bi₂O₃ system. These compounds have photocatalytic activity in the near-UV and visible range of the spectrum, which can serve to create photocatalytic concretes. Here, the purpose of this scientific study was to synthesize compounds based on the TiO₂-Bi₂O₃ system using two methods in order to identify the most optimal variant for creating a composite material and determine its properties. Within the framework of this article, two methods of obtaining a photocatalytically active additive based on the TiO₂-Bi₂O₃ system are considered: the solid-state and citrate-based methods. The photocatalytic, mechanical and structural properties of composites containing the synthesized additive are investigated. In this study, it was found that for the creation of photocatalytic concretes, it is advisable to use cement compositions with a bismuth titanate content of 3–10 wt.%. of the cement content, regardless of the method of obtaining the additive. However, the most optimal composition is one containing 5 wt.% of the synthesized additive. It is noted that compositions containing 5% by weight of bismuth titanate demonstrate photocatalytic activity and also show an increase in strength on the first day of hardening by 10% for the solid-state method and 16% for the citrate method.