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the article discusses the relevance of the use of composite materials in the reconstruction of exposed to heavy loads of concrete and reinforced concrete floors of industrial buildings. It is noted that at the present stage of development of the construction industry special attention is paid to the use of steel fibreconcrete, as this material allows with minimal material and labor costs to carry out work on the reconstruction of industrial floors. The novelty of this study is the use as an adhesive between the existing floor, which is to be restored and strengthened, and the newly laid steel-fiber concrete layer of polymer-bitumen composite material with the addition of cement and graphite powder, previously obtained by the authors experimentally. This material with the required thickness is also a structural layer for leveling the surface of the lower layer, reducing friction under the sole of the upper steel-fiber concrete layer and the existing floor. The paper presents the technology of work in the reconstruction. The composition of the steel-fiber concrete layer is adopted on the basis of studies by other authors. Despite the fact that the experiments proved the solidity and strength of the reconstruction of the floor by the developed technology, the article notes that the final characteristics of the proposed floor design and technology can be identified only during operation, which can be the basis for further research on optimizing the thickness of the layers proposed for use of composite materials. For the evaluation of economic efficiency of application of these composite materials in the reconstruction of the concrete floors in the course of the experiment, there are revealed some figures for labor and material costs.

This paper considers the importance of quickly erectable construction systems, as well as their main purpose and applicability in various situations. Based on the analysis of scientific publications and the results of patent search, the authors suggest the structural features and technological solutions for installation of a new small-size quickly erectable collapsible construction system. The system is designed for temporary accommodation of a group of people involved in construction, geological exploration and other works in hard-to-reach areas, for tourists etc. Such a collapsible construction system can be adapted to serve as a temporary shelter for people surviving natural calamities. The foundation of the suggested system is an enclosed three-dimensional structure (crate) where the necessary structural elements are kept pending the assembly of the construction system, including telescopic legs and other tubular framing structures, rolls of tent covering, set of coupling elements, and supports. The specific features of this new system, as compared to similar space planning solutions, are low labor costs involved in its assembly and dismantling, small weight ensuring transportability of a collapsed and packed system, and reusability. Other benefits of the new small-size construction system include its low overall cost, environmental safety and energy efficiency.

Abstract. The paper discusses the importance of building reconstruction and the need for improving the available formwork systems used for strengthening of structural elements during reconstruction. Citing the results of the analysis of the Russian and foreign scientific publications, the authors emphasize the necessity of replacing costly wooden formworks with high-technology reusable all-purpose and mobile formwork systems. Considering that such requirements are met by rubber-fabric formworks, the authors have developed a pneumatic formwork and showed by way of experiment that the labor intensity of installation and dismantling of such formworks is much lower as compared with conventional wooden formworks, which makes this research original. The paper further describes the design of the suggested formwork and the installation and dismantling techniques. The versatility of the formwork is confirmed by its ability to easily adapt to any structural elements (pier foundations, columns, beams etc.) ensured by the flexibility of rubber-fabric materials. This system can be used for structural elements having various geometric shapes (round, rectangle, trapezoidal) and dimensions. Their transportability is warranted not only by the dimensions and flexibility, but also by a small weight. The use of pneumatic formworks contributes to resolving the problem of conservation such valuable natural material as wood.

The paper highlights the relevance of using composite materials for reconstruction of heavy-duty concrete and reinforced concrete flooring in industrial buildings, stating that at the current stage of construction development special attention is paid to the use of steel fiber concrete flooring, as this material allows for reconstruction of industrial floors with minimum financial and labor expenditure. The novelty of the research lies in the fact that the adhesive between the flooring to be restored and reinforced and the new steel fiber concrete layer is a composite polymer-bitumen material with cement and graphite powder additives, which was previously experimentally developed by the authors. This material, given an adequate thickness, also serves as a structural spacing to level the surface of the underlying layer and reduce friction under the bottom of the upper steel fiber concrete layer and the existing floor. The paper describes the reconstruction workflow. The composition of the steel fiber concrete layer has been assumed based on the research of other authors. Although experiments proved the integrity and strength of the flooring after its reconstruction with the new technology, it is noted that the final characteristics of the proposed floor structures and workflow can only be assessed in the course of normal use, which can be the basis for further research aimed to optimize the thickness of the suggested composite layers. The experiment delivered certain labor and material cost figures for evaluating the economic efficiency of the use of the composites described below in the concrete flooring reconstruction.